Lister Engine Forum

How to / DIY => Generators => Topic started by: Johndoh on September 20, 2018, 09:30:10 PM

Title: Voltage drop under load
Post by: Johndoh on September 20, 2018, 09:30:10 PM
Hi guys I have a mongrel diesel generator. Thanks to you guys its working well and making power around 233 volts. Yesterday there was a lot of power outages and she got her first real work rant for 8 hours or so. I noticed the voltage dropped to about 210 volts when the water pump kicked in. It's only a half horse pump. Is this normal? It's 5kw AVR alternator. I should mention that there was a 50hz sticker on the frame when I got it so I checked the speed and it was running at 3600 rpm its no at 3000 rpm. Should I speed it up to 3600 again? Turn up the avr to maybe 245v?  It's extremely noisy at both speeds. I put new brushes and a new avr in it this spring. Any and all suggestions welcome!
Title: Re: Voltage drop under load
Post by: ajaffa1 on September 20, 2018, 11:08:19 PM
Hi Johndoh, If your generator was set to produce 50 Hz at 3600 RPM, running it at only 3000 RPM will only give you about 42 Hz.

A half horse power pump will pull a lot more than that when it is starting up, it might only pull 1 amp when running but it could, briefly, pull 10 amps while starting. The lower the voltage the higher the current draw will be. Most electric motors have the speed at which they rotate determined by the frequency of the AC supply they are connected to. A 50 Hz motor coupled to a 42 Hz supply will rotate more slowly and pump less water. The head to which you are trying to pump water will also have an impact on how much current it draws.

A lot of smaller generators loose voltage during prelonged running. This is because the wire coils in the alternator warm up under load.The heat increases the resistance in the wire causing the voltage to drop.

My Lister ST2 7.5 KVA generator produces 245 volt when cold, this drops to around 235 volts after about ten minutes. When the domestic water pump kicks in, the voltage will drop to around 220 volt before the governor kicks in to pump more fuel, the voltage then quickly climes back to 235 volts.

hope this helps,

Bob
Title: Re: Voltage drop under load
Post by: Johndoh on September 20, 2018, 11:35:03 PM
hi ajaffa I was under the impression that 3000 rpm = 50 hz and 3600 = 60 hz? I would be pretty easy to put it back but I was kinda afraid Id blow up the TV but I suppose the AVR is supposed to prevent that? There was a little flicker off the light but I assumed this was normal.
Title: Re: Voltage drop under load
Post by: glort on September 20, 2018, 11:40:30 PM
+1 to everything Bob said.

With generators I maintain that frequency is more important than voltage and this is a perfect reason why.  Voltage will always wander a lot more than frequency and if the frequency is right the Volts will be close enough.

I would set the genny speed not by the RPM but the frequency of the output with a Load on it, 2Kw would be about right for this machine.
Run the genny with a 2KW or close to it load and measure the frequency with a Multimeter and set your engine speed from that.   Almost certain that the engine speed will not end up at 3600 exactly but something else.  once you set the speed, unload the engine and see where the frequency goes. Ideally you want it at 51-52 Hz but it will depend on the Governor on the engine.  Just make sure it's not too high.

Would also pay to give the engine a once over. Make sure the air filter isn't clogged which will reduce the engines ability to carry a load.  Same for fuel filter. make sure exhaust isn't restricted with wasps  nests carbon or anything else although after the run you gave it, that would not likely be a problem now. Some diesels have upper limits on the fuel rack as well as idle and run settings so make sure you are getting enough opening there to carry the full load. As things wear they may need more fuel to do the same work when the thing had less hours and compression, vale seats etc were better.
Change the oil for good measure.

If you haven't already, run the thing up to temp, remove the air cleaner and give the thing a good spray down the intake with a litre or more of water to give the thing a good clean out internally.  This can help remove buildup in the cylinder, Rings, ports, Vale seat area and the exhaust.
After all that the thing is probably going to be close as it's going to get to being right apart from the injection timing which is usually set on most small diesels by shimming the pump. Not normally needed to be adjusted ( except for one engine I got that was so advanced it sounded like the piston was hammering the head)  but if the thing is a bit old you could try pulling a shim or 3 and see if the thing has more diesel clack which is a good thing and generally indicates better performance.

What sort of Genny actually is it? One of those red or black China vertical Cylinder yanmar Clones?
Title: Re: Voltage drop under load
Post by: Johndoh on September 20, 2018, 11:55:46 PM
Hi Glort its a real yanmar! I serviced it new air and fuel filter and its runs well with no smoke. I don't have a meter that can measure frequency so I can only rely on the RPM. I maybe shouldn't have lowered the speed? It ran the other day for about 8 hours and apart from the drop in voltage all seemed well. The voltmeter on the generator stayed at 230 ish but the separate voltmeter I have on the little homemade board showed a drop. Maybe its faulty?
Title: Re: Voltage drop under load
Post by: ajaffa1 on September 21, 2018, 12:02:26 AM
Hey Johndoh, the alternator should have a metal plate on it stating the voltage and frequency at a given RPM.

A lot of generators run at 1500 rpm for 50 Hz and 1800 RPM for 60 HZ (USA), This would equate perfectly to 3000rpm for 50HZ and 3600 for 60 HZ.

Bob

Title: Re: Voltage drop under load
Post by: ajaffa1 on September 21, 2018, 12:32:52 AM
Just a thought on the voltage drop. A 5 KVA generator kicks out a maximum of about 20 Amps. A standard UK extension lead has only 2.4 mm wire in it. This would only be rated at about 15 Amps. Pulling 20 Amps through it would cause it to heat up increasing the resistance and lowering the voltage at your distribution board. The longer the cable the more voltage drop. Leaving any part of an extension lead rolled up causes induction making things worse.

Bob
Title: Re: Voltage drop under load
Post by: glort on September 21, 2018, 12:43:00 AM
Have a look on fleabay for multimeters.  They are so cheap now it's crazy.
I received 3 new ones yesterday.  I have a perversion for the things.  They even come in funky colours now.  Might put them all in that spare display cabinet I have and make them a decorative feature in the lounge room.  Mrs has all her ornaments and vases and other cra... trinkets in there, only fair I get  to put my touches on our home decor.

You should get a meter  that does frequency for about $10 whatever your equivalent of that is. Should equate to less than a feed at maccas or a coffee and cake at a Cafe.  Plus the multi meters are non fattening so you'll still look good for the Mrs, won't upset your Diabetes, cholesterol, heart, kidneys or anything else us old farts have to concern ourselves with!   :embarassed:

They are a handy thing to have for this very purpose and many others. Spending 20 bucks/euro will get you one with a heap of other useful features as well. 
Title: Re: Voltage drop under load
Post by: Johndoh on September 21, 2018, 12:50:58 AM
Hey Johndoh, the alternator should have a metal plate on it stating the voltage and frequency at a given RPM.

A lot of generators run at 1500 rpm for 50 Hz and 1800 RPM for 60 HZ (USA), This would equate perfectly to 3000rpm for 50HZ and 3600 for 60 HZ.

Bob

Hi Bob
It used to be a silent type generator in an enclosed frame I believe there was a plate beside the 50hz sticker but that stuff was taken off and dumped. I'm thinking I should get a kill a watt, are they any good?
PS I'm not using a standard extension lead there has been a 32 amp plug installed because theres a big output socket on the generator I am using a heavy caravan/camper van hook-up lead, the power is disconnected in the house before the generator can supply power.
Paul
Title: Re: Voltage drop under load
Post by: glort on September 21, 2018, 12:58:00 AM
Just a thought on the voltage drop. A 5 KVA generator kicks out a maximum of about 20 Amps. A standard UK extension lead has only 2.4 mm wire in it. This would only be rated at about 15 Amps. Pulling 20 Amps through it would cause it to heat up increasing the resistance and lowering the voltage at your distribution board. The longer the cable the more voltage drop. Leaving any part of an extension lead rolled up causes induction making things worse.

Bob

This is a good point and one I come up against with my solar setup.

I'm amazed UK leads are 2.4mm wire. Most leads here are only 1MM conductors but rate the cables to 2400W which may be OK for a 1M lead but for a 20 or 25, it's BS. The biggest lead I can find in standard, non 3 phase configuration is 1.5MM which is still marginal but rated " heavy duty".  I have looked far and wide but 1.5 is the largest conductor area I can find.

The resistance works both ways, as well as voltage drop when pulling through a lead, you get voltage rise when trying to push down it. Nothing I have tried in a commercial lead is really up to snuff in the longer 20-25M lengths for their rating.
I just bought some 2.5MM builders cable, cut a long length of that and put some 15A plugs on it. Used 15a not because of the rating so much Pins are the same size bar the earth which I file down)  but because the terminals are bigger to get the larger diameter wiring into and make good connection. Still a trick though.

If you look on google for resistance and power ratings of leads, You'll likely be surprised at the power fall off and the diameter you need to properly feed higher loads.  As said, If the voltage is low on the genny end, on a longer lead it's going to be dismal time it gets to the load and the amps will go up making the problem cascade for the worst. 
In this respect, getting your voltage up to 250 if you are not going way over the frequency will be a good thing. The more volts the less amps.
The upper limit for voltage is 253 on a 230V circuit so You'll still be in spec.
Title: Re: Voltage drop under load
Post by: Johndoh on September 21, 2018, 01:18:36 AM
Hi Glort,
I can easily raise the voltage on the AVR but would it help? The house was wired for a 2 HP water pump to draw water for cattle but the pump was never upgraded and the landlord sank another well for the animals. The wires are about 6mm similar to an electric shower cable and the hook-up cable is about 5 mm so fairly heavy.(including insulation so maybe 4 and 3 mm actual cable) This is the connection the guy wired up. It's not really too big of a problem I suppose, until recently i was using capacitor generators and extension leads and all was ok but then I knew no better until I started reading stuff on this forum, which got me worried/thinking/panicking etc

P
Title: Re: Voltage drop under load
Post by: Hugh Conway on September 21, 2018, 01:29:27 AM
Hello Paul
One of those Kill-a-Watt plug in meters are very handy to check volts and freq from any receptacle, as well as load from anything plugged into it. They are just handy to have around. Also as Glort says, meters are cheap.
I have wired in V and Hz meters before my main  generator switch so I can see if all is well before going on-line. Then an ammeter is good to have in the circuit too. Usually 1500 or 3000 rpm will give 50Hz and 1800 or 3600 rpm for 60Hz/
I am clueless re an AVR as my gen set-up has a PMG, so both Hz and voltage are rpm dependent. Better to run over a bit on Hz than under. Low Hz (like low voltage causes more heat build-up) I do run some 50Hz rated appliances at 60Hz with no problem, but have been told that going the other way can cause overheating.
Cheers,
Hugh
Title: Re: Voltage drop under load
Post by: dieselspanner on September 21, 2018, 08:40:10 AM
Put one of these on it, a 20 min job to knock up a bracket and two bits of wire out of the 'come in handy box'

Cheers

Stef
Title: Re: Voltage drop under load
Post by: Johndoh on September 21, 2018, 08:41:31 AM
Hi Hugh
I'm going to order a proper multi-meter with hz function today. I will also recheck the rpm and increase the voltage to about 240v. The vessel for the water holds about 50l it has a diaphragm so the pump didn't have much to do. I have been looking at small generators on the interweb and it seems you can buy 120/240 v 3600 rpm generators which is really confusing for me. This was an old generator when I got it for cheap but it was running at 3600 and making power with no ill effect before I checked the revs so maybe thats as it should be? A little knowledge is a dangerous thing in my case!

P
Title: Re: Voltage drop under load
Post by: Johndoh on September 21, 2018, 08:57:36 AM
https://www.ebay.com/itm/Yanmar-6KW-Diesel-Generator/183384598167?hash=item2ab292e697:g:pBIAAOSw-mdbdzYO

I am probably worrying about nothing
Title: Re: Voltage drop under load
Post by: mikenash on September 21, 2018, 09:31:51 AM
Hi Hugh
I'm going to order a proper multi-meter with hz function today. I will also recheck the rpm and increase the voltage to about 240v. The vessel for the water holds about 50l it has a diaphragm so the pump didn't have much to do. I have been looking at small generators on the interweb and it seems you can buy 120/240 v 3600 rpm generators which is really confusing for me. This was an old generator when I got it for cheap but it was running at 3600 and making power with no ill effect before I checked the revs so maybe thats as it should be? A little knowledge is a dangerous thing in my case!

P

I have a 5kVa gen head here that's 20-years old.  3000 RPM for 50 Hz (actually recommends 3150 RPM unloaded).  And 3600 RPM (actually 3750 unloaded) for 60 Hz
Title: Re: Voltage drop under load
Post by: Johndoh on September 25, 2018, 03:15:15 PM
So I did a load of checks and tests and reread all the posts here. Seems ajaffa et al was on the money. The vessel for the pump is 10 feet for the generator the extension lead is 50 feet and about 42 feet was coiled. Rookie mistake on my part, thanks to all
Title: Re: Voltage drop under load
Post by: glort on September 25, 2018, 03:56:32 PM

For anything remotely high load, always pays to use the shortest lead possible.
Doubly applies when leads are normally made from Pissy little 1.0mm cable.  The " heavy Duty" ones available here with 1.5mm conductors are not much better.
Title: Re: Voltage drop under load
Post by: Johndoh on September 25, 2018, 04:26:43 PM
Glort the things you can learn on forums like this are staggering. Like I posted earlier my house was wired for a heavy duty water pump but the connection was never used. My "electrician" has wired a connection to it that simply backfeeds to the house. I have to turn off the main switch before connecting the generator bit of research says he lied and I DO need a changeover switch. Grrr
Title: Re: Voltage drop under load
Post by: Barenburg on September 25, 2018, 08:10:51 PM
That clearly depends on the definition of need.

1. Need to make it Fool Proof?  yes
2. Need to meet code? probably
3. Need it to work correctly when tended by a competent person?  no
Title: Re: Voltage drop under load
Post by: Johndoh on September 25, 2018, 08:49:16 PM
That clearly depends on the definition of need.

1. Need to make it Fool Proof?  yes
2. Need to meet code? probably
3. Need it to work correctly when tended by a competent person?  no

I was reading somewhere that you shouldn't backfeed power with the breaker switched to off? I am allegedly the competent person however I like to do things as well as I can. The guys on here know that I know very little about electricity and I no nothing of the code in Ireland the chap that did the wiring for me is a qualified electrician. I only recently got the generator on electric start it's now connected to a solar charger so battery will always be charged. I'd just use the pull start but I'd like it easy for the missus. If she forgot to throw the breaker....
Title: Re: Voltage drop under load
Post by: glort on September 26, 2018, 04:21:26 AM

The whole thing about having to have isolator/ change over switches for the safety of line men working on repairs is one of the great parroted idiot mentalities on the net far as I'm concerned.

The moral High road ignorants purport that if you have a generator running, it will energise all the wires from outside your property to claims I have seen of 5 Miles away.  What a complete and utter crock of shit!

When the power fails, everything in your home does not automatically shut off, many things will stay connected ready to kick on the second there is power.
If there was a power faiure and you connected a genny, in order for the linemen to get zapped, Your genny would have to power everything still connected to the mains.  Every chance that could be most of the homes in your street at very least. I don't know how big these brainwashed zealots think most peoples backup genny is but I would guarantee there are very few people in the world that have a back up genny capable of powering their whole street. Even if they did, the max power they could provide would be limited by the lines connecting their property to the street.  More likley, the wiring between the genny and the household mains is going to be a much lower rating than that so the load any genny could carry without instantly tripping when connected is very limited.

Maybe the break in the line is just up the road and the isolation is 5 Homes. Has your genny got the grunt to run all the fridges for instance when they kick on or pumps and other things that would still be connected and ready to go?  Not a chance in hell or anything like the safety zelots make out.
Good chance at some point there will also be a transformer on the pole still in circuit. You think your little home genny is going to be able to energise that even if it has no load?  If you are isolated and the next place is a way down the road, the impedence and resistance of just powering the grid lines are going to be enough to knock out most home size gennys if not all.

There is also one big flaw in this paranoia.....
It's standard practice for any power work far as I can tell in the western world, to clamp the Lines before touching them and doing any work.

 They get a Big metal bar and securely bolt it across the wires to create a dead short so the lines are dead even if they are some how energised.
That is to stop any active current as well as anything being connected and energising the lines while work is being done.  Not always possible to disconnect the lines from everything so this is a simple, easy and standard practice. If people think their genny has the grunt to blow through a 1" Copper bar across the mains lines, They must have quite a grunty beast in the back shed.

 I have pointed this out before and then the zealots say something moronic like " If there is even a Million to one chance someone could get zapped...."
There is better than a Million to one chance they will get cleaned up and killed in a motor vehicle accident going to and from work and a much greater chance of them having some other accident in the high risk work they do so a million to one chance would be a lot better odds than things the moral high grounders are blissfully ignorant to. Typical internet brainwashed safety sissys.


It is because your genny could be trying to power everyone elses home in the street you do need an isolator or change over switch. "Lineman" safety is an idiotic ignorance.

I can imagine the Load that would be dropped on any generator when you connected not only the live circuits in your house but maybe the ones in the homes either side as well or 10 others in the street. Thing is going to trip immediately unless your back up genny happens to be a 60Kva driven by a 6 cyl Diesel and the whole thing weighs 2.5 Ton. Of course no matter what other loads you would be connected to, most people probably don't want to be powering all their Neighbors places in the street for too long anyway.

Also if there was a short on the mains lines like a tree had taken wires down or one was grounded, you may not be able to get your genny to connect through the short or RCD tripping out.  For these reasons you need a disconect of some sort.  Flipping the main switch would be enough but if the genny is hard wired you need to be able to connect it.
Suicide cables (lead with male plugs either end to connect outlet to outlet)  are another internet paranoia but at least there is sound reasoning behind the discouragement of their use. Never a good idea except in absolute emergency's and every possible precaution taken with them.

Change over switches can be had in automatic, remote and Manual these days and are not that exy.
They are a good idea if you want to be able to back feed but not for the reasons most sensationalists on the net will parrot over and over as usual, without bothering to think though what they are saying.

I'm afraid I have little respect for Regulations and " qualified" sparkys. Yeah, of course, as you always have to state the obvious, there are good ones out there but unless you know someone personally, you first time at least with one is always a risk.
I have done a LOT of my own wiring here and my sparky mate tells me a lot of it is not up to regulation because I have too MANY breakers and wired in heavier duty circuits than is allowed.  Work that one out.

Here, a lot of circuits can be fused at or above the rating of the wire. All my fuses are undersized so they will well and truly be the first things to trip.
I live here. I'm in no rush to get to the next job or do things to the minimum standard. If it takes me all day to do something and I spend double what I could have, so what?  I can always go to bed and lie awake at night as I do thinking about anything and everything rather than if my wiring is going to cause a fire.

I know my limitations and that even if I do stuff up, there is an under rated breaker at the start of everything I have done that will trip way before anything causes any problem at all.
When there is stuff that's out of my league, I get my sparky mate in...... Who generally looks at what I have done, shakes his head and walks off laughing at the over the top way I did things telling me I didn't have to go to all that trouble.  Worth every minute and cent to me. 

I have found plenty of wiring here that is dodgy but is the original wiring that would have been done by a licensed sparky and then passed by a building inspector.  So much for worrying about what the Unqualified hacker did..... Who as it was came along and fixed the things that should have never been done in the first place.


Title: Re: Voltage drop under load
Post by: Johndoh on September 26, 2018, 08:30:23 AM
So my system is ok apart from the changeover switch I need in case the wife plugs in the generator without throwing the breaker?

I did a little research and made a few calls yesterday. In order to fit the changeover switch you have to remove the main fuse coming into the house. This fuse has a lead seal on it so you have to notify the electricity company that you broke the seal so they can come out to re seal it and inspect the work. A qualified electrician cannot do this unless he is registered as well as he has to sign off on the job.  This is part of the code so retired electricians can't do this job as  obviously they forget a lifetimes work the first day the collect their pension.

A 125 amp switch is only about 40 so I will order one this week. The cable leading from the generator to the changeover switch has to be 20 square (wtf does that mean?) and it has to be installed "properly" which I assume means attached to the walls or buried underground? I have a feeling all this is going to be very expensive.
Title: Re: Voltage drop under load
Post by: glort on September 26, 2018, 11:20:14 AM

20 square would be 20 sq MM conductor area. Commonly known here as 6mm.
In 240V, depending on your regulations and installation, that's good for around 100 Amps or 24 KW.  Usually depends on the length of the run back to the board as well. Further you go the more resistance and the larger the cable required to keep both the heat rise in the cable and the voltage Rise/ drop within the limits.  Try to push too much power down the line from solar inverter in the shed back down the too far away main circuit at the house and you end up with 259 at the solar inverter and 241 at the other end..... So I'm told...... I'd never have a problem like that......   :angel:

I was looking to put 6mm up the back but it will depend if I can get that up the conduit.  4mm will be OK for the house arrays when I get it done because the run back to the box will be much shorter.  I also want to put 2 Circuits for 2 arrays on 2 seperat phases so the load on each will be a max of 5 Kilo. 4mm will be heaps for that anyway.

How far do you have to go with this? 6 MM and above starts getting exy here.
Installed properly is probably the all encompassing term for meeting regulations. this will pertain to where the cable is run, switched and fused, depth of burial if it has to be, Conduit rating for in ground and UV exposure if that comes into it, securing, grounding and so it goes.
Sound a lot but most of it is a given.

If you are going to need a trench, might save a few bucks if you dig it yourself. Then again, if they have a ditch witch, probably wont take long and may be worth paying them.

I'd also look at a control panel for the genny.  You'll need it to be isolated at both ends of the line most likley But I'd be looking on fleabay for meters that tell you amps, volts, frequency as a basic.  You can get cheap meters like the all in ones with the inductive sensor which I have a few of and seem very good over the couple of years I started using them or you could get individual meters in digital or analogue for aesthetic reasons.

If you want to impress your friends and put Look hot to the Mrs, at least once, throw some of those industrial looking warning/ indicator lights on the panel along with some equally unessacary as well as required switches. You can put a Light on the main sub  board switch which has little purpose other than to indicate connection to the mains and  make the whole thing look good and elevate your apparent technical prowess to operate this  very technical looking bit of gear with all the switches and gauges and lights it has.
You can have another switch and an indicator light ( they come in 5 Colours, I bought 5 of each and they cost less than a buck apiece) that turns the meters on.  Not in any way required but if you are going to do this, may as well have all the fun and satisfaction you can with it and milk it for all it's worth!  :laugh:
Another breaker and indicator for the starter for the engine and a volt and amp meter for the battery charging circuit and so it goes. With a bit of imagination and a little cash, you can have something that will have people in awe and asking how on earth did you learn how to work all this complicated machinery?

For bonus points, add one of those big red emergency shut down slam switches and a couple of Knife switches... the more old school and scary looking, the better! Also Don't forget to print off and laminate some of those " DANGER- High Voltage " signs and Others like " Authorized Personnel Only" and
" safety equipment must be worn at all times".

You don't need to know about this stuff for family and friends to think you are an electrical god!  ;D
My friends and Family think all my mucking around with electrical stuff is because I'm in a hurry to meet god, or the other fella, but that's a different and less creditable perception you would be better to avoid.  :embarassed:

By the same token with all of this, you can set up a remote starter that will require no more instruction to the Mrs than " If the lights go out, press this" and mount it on the kitchen wall. 
.
Heres a couple of pics for inspiration for your control panel of awe!  :laugh:

(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcR04Y8Noc_1iDVHPH3N8mqIMkcehg2_8WrSfoRH1ak96G5dXGOo)

(https://4.imimg.com/data4/NG/PV/MY-697673/generator-control-panel-500x500.jpg)

(https://4.imimg.com/data4/BA/EB/MY-4127294/control-panel-of-motor-generator-set-dc-to-ac-500x500.jpg)



Title: Re: Voltage drop under load
Post by: ajaffa1 on September 26, 2018, 12:08:36 PM
Hey Johndoh, yes a cross over switch is the way to go, not expensive nor difficult to wire up. you can legally do all the work yourself except for rerouting the incoming mains supply. I wired dozens of houses in the UK and just paid an electrician to test it and connect it. Cost for testing/connection was about 300. For what you are doing probably 100. Not too drastic and you get a certificate confirming compliance in the unlikely event that something goes wrong. Probably a good idea to send a copy to your insurance company so they can`t wriggle out of their responsibilities should something bad happen.

Bob
Title: Re: Voltage drop under load
Post by: Johndoh on September 26, 2018, 08:08:30 PM
The yard is concrete so the cable will have to go inside a conduit under the eaves, I like Glort's control panel idea but really simplicity is all I want a few lights tv etc. I dont have many visitors they want my good coffee, the same bastards that give me weak instant coffee, they want to borrow stuff (I refuse). I will put it all in the hands of a spark that's still registered and I'll be covered. I kinda miss the little Kohler petrol generator and the exntention lead with 2 sockets, TV and a standard lamp.
Title: Re: Voltage drop under load
Post by: ajaffa1 on September 27, 2018, 09:42:52 AM
Hey Johndoh, don`t pay a sparky to fit conduit and pull cable. Doing that bit yourself will save you a fair bit of money. Just let him do the clever bits at each end. I expect he is probably getting a considerable trade discount on cable and conduit, ask him to drop off the gear and tell him you`ll call him when you`ve done the donkey work.

Bob
Title: Re: Voltage drop under load
Post by: Johndoh on September 27, 2018, 09:53:24 AM
Hi Bob

I saw on a different forum that you need to have the spark modify the cable you plug into the generator but it didn't say how why etc? Something to do with earthing it. The generator is earthed to 4 x 1m iron rods each about 2m apart.

thx Paul
Title: Re: Voltage drop under load
Post by: ajaffa1 on September 27, 2018, 12:43:30 PM
Hi Paul, not sure about the earthing issue. Here in Australia the regulations are a bit different but I still like to go with what I used to do in the UK. I have one ST2 7.5 KVA generator, It has it`s own earth stake connected to the Generator head then the top box and then cross bonded to the engine and fuel tank.

There is an original Lister SOM control box in the shed, this has three 6 mm squared wires feeding it, two for AC current and one for earth.

I have a distribution board connected to the output from this setup. It has it`s own earth stake which is also connected with 6 mm cable to the control box.

From there the (6 mm) 2 live/neutral cables and earth cables run underground to the house distribution board where they link up with a cross over switch and another earth stake which is bonded to the previous two.

From there I have a feed going back to the shed to provide lighting/power etc. I have another distribution board with another earth stake.

So to make this as simple as I can: the generator requires connection to an earth stake with any parts separated by non conductive materials cross bonded. All distribution boards should have their own earth stake. All earth stakes should be connected to one another through the earthing bars in the distribution boards.

I strongly recommend that you water the area around the earth stakes prior to any testing by the local electricity authority if the weather has been dry for more than a week or two.

Bob
Title: Re: Voltage drop under load
Post by: glort on September 27, 2018, 02:24:23 PM

Earthing regulations like many things electrical are a dog's breakfast here.

I'm pretty sure there is something about NOT earthing gennys but I can't remember if that is portable types or Fixed ones. One would think that fixed machines would need to be but I forget what portables are not suppose to even though most I have seen have an earth terminal on them for grounding.

I also know that the earth is supposed to be able to carry the current of the live and neutral sides.  I have cable up the back that is made here ( and recently bought) that seems thinner than the other 2 conductors so......

There are also regs for the size of the earth rod in Length and depth.  Earthing to buried water pipe is no longer allowed.... for sound reasons.

I had a metal covered trailer years ago I had computers in and covered events with.  We had a problem at one place where were were getting a strong buzz when we were getting in and out of the trailer and touched it.  Sparky mate was there and I got him to come look. Shut it down and went through the wiring  I had done and couldn't find a thing.  Tested the trailer with a meter and there was power going through it.
I had a steel rod in the trailer I used for staking an awning so I pounded that in the ground and clamped a pair of jumper leads between it and the trailer. Problem solved.

Mate said I don't know what's going on but I'll look at the thing again during the week.
Shortly after we heard someone saying things in the canteen were playing up.  We both wandered over to have a look and heard of things going weird. Mate and I knew what it was.  We went round to the fuse box, were looking at the wiring and I discovered the earth connection looked like it had been broken off the ground rod by someone  dropping a metal bin on it.  We reconnected the Wire, went back to the trailer, removed the jumper cables and all was fine.

Mate thought it was probably something amoung the old equipment in the wet kitchen creating a path from one of the live wires and somehow back feeding maybe through the neutral wire.   Bloody lucky no one including us in the trailer outside got fried.
Mate went to his vehicle, found an RCD and made a donation to the club by installing it.

After that I put and RCD in the trailer as well and always grounded the thing wherever we went.  Sometimes it was to a nearby metal fence post, a metal rail or I used the metal rod. A lot of these places we went were old dodgy places and some had their own gennys so I was wary after that.
The whole trailer was aluminum and I spose we would have been fine inside but having one foot in and one out was the danger.

You sound like you have yours well covered Bob.  Never too much of a good thing like that in my book either.


Title: Re: Voltage drop under load
Post by: Johndoh on October 09, 2018, 03:20:27 PM
I had another spark out to do a quote. He told me 16 square cable would be fine for what I want. He said he would have to do tests on the negative wiring before he could do a quote. No clue what he means there. He thinks the backfeed I currently have would be fine reckons the less the state knows about what you do the better! He also suggested I dispose of that "dirty, noisy fcuking thing" and just use a small petrol inverter generator with a cable through the window for tv and lights. He's full of ideas anyway
Title: Re: Voltage drop under load
Post by: BruceM on October 09, 2018, 06:53:46 PM
Electricians vary greatly and in many states and countries have almost no technical training to speak of.  In my state not even a HS diploma is required.  Some have completed their apprenticeship managing to learn almost nothing.  Others with interest and aptitude may be much more knowledgeable on power hookups than the typical engineer.

There is no such thing as negative household wiring.  Perhaps he said neutral and you heard negative.
Title: Re: Voltage drop under load
Post by: Johndoh on October 09, 2018, 09:48:21 PM
Electricians vary greatly and in many states and countries have almost no technical training to speak of.  In my state not even a HS diploma is required.  Some have completed their apprenticeship managing to learn almost nothing.  Others with interest and aptitude may be much more knowledgeable on power hookups than the typical engineer.

There is no such thing as negative household wiring.  Perhaps he said neutral and you heard negative.

Could be neutral he spoke quite fast and there was a lot of expletives! He is a registered qualified spark, he has to be to sign off on the work and he has to break the seal on the main fuse to do the work. That's illegal here in Ireland unless youre registered etc, I'm sure people have done it but I try to stay on the + side of the law however thin the margin is. It might be down to me if he was a chancer.
Title: Re: Voltage drop under load
Post by: glort on October 09, 2018, 10:51:37 PM

There is no such thing as negative household wiring.  Perhaps he said neutral and you heard negative.

I have heard 2 solar installers now call leads from panels " The Plus and the Minus wire" .
If positive and Negative is too technical for them, not people I would have touch anything I own.

Quote
eckons the less the state knows about what you do the better! He also suggested I dispose of that "dirty, noisy fcuking thing" and just use a small petrol inverter generator with a cable through the window for tv and lights. He's full of ideas anyway

The first part about letting the state not know about what you are doing is both encouraging and worrying at the same time.
The bit about having a petrol Generator with a lead going through the window concerns me.  Does he not want the state to see or inspect his work?
For a sparky to say put a lead through the window seems odd to me.  If you told him you want to run a genny for money saving then it's going to be a more permanant thing. If you said you want it for blackouts then I can understand.

Golden rules is 3 Quotes. Maybe you'll get 3rd time lucky with these guys?

Couldn't agree more with Bruce about sparkys. They tend to have very limited knowledge here in that they are like Doctors in a specialty. They know domestic or industrial or whatever they do but VERY little else. Not met one yet that I could talk to about IMAGS although they have heard of it but know  nothing about them.  Same with a lot of other DIY type things.  They know well what they do every day but outside that, zero.

There is a rule here about breaking the seals on the main Fuses. It's so you can't rewire the meter connections so they run backwards or put a jumper before the meter etc.  No one really gives a damn. Very rare to see Fuses with the seals still on them in older places.  Even meters. 2 of mine are unsealed and were when I got here. Just pulled my main fuses when I wanted to re wire the board... technically Illegally.

The place here has 3 phase, 2 meters are analouge so I can back feed them with my solar and run the meters backwards. The 3rd has an electronic meter which I can't  with the off peak hot water ripple switch built in.  I took everything I could off that which just left the 3rd leg of the 3 phase AC.  Everything else is on the other 2 phases.
Technically that's illegal because the load is supposed to be spread over all 3 phases to balance the loads and consumption.

The stupidity is it's rare now unless asked, for new homes to have 3 phase. It's all on the one phase and there is no regulation for which phase you use.
It's more than possible a whole street could be on the one phase with the other 2 untouched.  The fact the connections are basically random is what they rely on for balance. often the 3 phases are brought down from the pole to the home but only 2 are connected on the board.  The loads I have on each of my 2 phases are still well under the load rating of each phase which is 60A but because the load on the 3rd phase is the lightest with only the air which would only pull about 3 Kw max, Technically it's not compliant.

Funny enough, the real loads I put on my system are not in fact draw but backfeed. I regularly push back at a higher rate than what I ever draw through the meters because all my Big loads are done though the day and the solar feed offsets them in the circuit so there is much less going through the meters and often that's still a small backfeed rather than draw.  When I have nothing doing and doing high solar output as I have recently, there is a load more power going back through the 2 phases which they are connected to that what is ever pulled through them. Only appliance with and decent load that's likley to be used when the solar is not running is the electric stove and the 2 ovens.  They are split phase anyway so are unchanged from the original 2 phases they were wired to and share that load as they always did.

There are a lot of rules and regulations with power but at the end of the day in practicality, it tends to come down to the beliefs and preferences of the guy doing the work.
Title: Re: Voltage drop under load
Post by: Johndoh on October 10, 2018, 08:39:13 AM
Glort I think he meant that power outages are usually short lived in Ireland and they don't happen all that often. The state here is very hands on as in hands on wallets, they want a cut of everything earned and an annual "inspection fee" for everything else. A friend built a house 15 years ago and the wiring for the generator was installed during construction. This was during the celtic tiger era when construction standards were self certified by the builder and there were no government inspections so in his case they don't know that it's been done.

Another quote might be a plan as #2 spark wasn't cheap although he does seem to know what he's doing. Can anyone explain (in laymans terms) about the issue with the neutral wires? Is it an extra money thing for the spark? 
Title: Re: Voltage drop under load
Post by: ajaffa1 on October 10, 2018, 09:50:12 AM
Hi Johndoh, I think I understand what your sparky is concerned about. The grid system in Europe works with a neutral wire that you can safely touch without getting electrocuted. The positive/live wire goes from about +350 volts to -350 volts giving 240 volt RMS. If you touch this wire you will probably die.

Depending on the generator you have and how it is configured you could have a system in which the positive wire goes to +350 volt and then the negative wire goes to - 350 volt, still 240 volt RMS, but any piece of equipment in your house that has been earthed to neutral (a very common practice in modern electrical consumables) will become live and kill you.

Bob
Title: Re: Voltage drop under load
Post by: Johndoh on October 10, 2018, 10:30:33 AM
Hi Bob
Thanks for the info I understand about 25% of it. So could my house be unsafe backfeeding? Is there a way to fix this problem if I have it?
Paul
Title: Re: Voltage drop under load
Post by: glort on October 10, 2018, 10:37:19 AM

Depending on the generator you have and how it is configured you could have a system in which the positive wire goes to +350 volt and then the negative wire goes to - 350 volt, still 240 volt RMS, but any piece of equipment in your house that has been earthed to neutral (a very common practice in modern electrical consumables) will become live and kill you.


How would this happen Bob?
As in wiring between 2 Phases  instead of a single phase and neutral?
Title: Re: Voltage drop under load
Post by: ajaffa1 on October 10, 2018, 11:25:01 AM
Hi Guy, there is a very simple way to check, Fire it up and then put a volt meter between the neutral and the earth, anything more than a couple of volts and you have a problem.

Yes wiring between two phases could cause this. Had a similar problem in UK hospitals years ago where they had three phase power. somehow they managed to split the phases so you had one phase on one side of a corridor and another on the other side of the same corridor. A whole load of cleaners got hurt using powered floor polishers, they were fine until they bumped the polishers into one another and then all hell broke loose.

Bob
Title: Re: Voltage drop under load
Post by: ajaffa1 on October 10, 2018, 12:15:03 PM
Hey Paul, I`ll try to explain this in as simple terms as I can. Try to imagine a water pump that pumps water from a well and then changes direction and pumps it back again. (How AC current works) The well is the neutral and depending on which way the water is flowing determines positive or negative pressure. (+350 volt, -350 volt could be +350 psi then -350 psi) Any piece of equipment that is connected into that pipe will be able to draw power. However you set this up there is never any pressure in the well (neutral). If you cut the pipe you will get wet from the pumped side but nothing from the neutral, well side.

Now try to imagine the same system without the well. A sealed system in which you pump water around a loop and then you reverse the pump and pump water in the opposite direction. Any piece of equipment plumbed into this system will be able to extract energy but there is no neutral point. If you cut the pipe you are going to get wet from both directions until the water feeding the header tank runs out.

Hope this helps,

Bob

Title: Re: Voltage drop under load
Post by: glort on October 10, 2018, 01:12:39 PM
Yes wiring between two phases could cause this. Had a similar problem in UK hospitals years ago where they had three phase power. somehow they managed to split the phases so you had one phase on one side of a corridor and another on the other side of the same corridor. A whole load of cleaners got hurt using powered floor polishers, they were fine until they bumped the polishers into one another and then all hell broke loose.


Geez! That does not bear thinking about! Even if they are 10A fused, you are going to have double that being 10A from each side when they met. And of course only one side is going to be fused, so for a split second.... BAM!  Scary to imagine!
Seems to me they would be lucky just to get hurt.  I'd think death would be a much stronger possibility.

It would seem then that the generator would have to be suitably wired.  Many units can be either in Wye or Delta but the house wiring, depending on how it was done may not be compatible with that. If you had the genny wired in Delta, that's going to give you the live neutral because you are jumping across the phases.  Not sure about the house wiring but it would seem to me that the genny would have to be checked to be running in Wye and if not, if it could be from the engine speed or gearing POV as well as the frequency.

More to consider here than what I have previously thought about.
Title: Re: Voltage drop under load
Post by: Johndoh on October 10, 2018, 01:13:26 PM
Hi Guy, there is a very simple way to check, Fire it up and then put a volt meter between the neutral and the earth, anything more than a couple of volts and you have a problem.

Yes wiring between two phases could cause this. Had a similar problem in UK hospitals years ago where they had three phase power. somehow they managed to split the phases so you had one phase on one side of a corridor and another on the other side of the same corridor. A whole load of cleaners got hurt using powered floor polishers, they were fine until they bumped the polishers into one another and then all hell broke loose.

Bob

I will do this later on is there any way to resolve this problem if I have it? Suddenly the portable generator with an extension lead doesn't seem that bad!

I just checked there's 283 volts between neutral and earth
Title: Re: Voltage drop under load
Post by: glort on October 10, 2018, 01:15:28 PM

Do you know if your Genny is single or 3 phase?
Not sure that it matters, I think the problem can exist either way depending on how they are set up.

Title: Re: Voltage drop under load
Post by: Johndoh on October 10, 2018, 01:19:12 PM

Do you know if your Genny is single or 3 phase?
Not sure that it matters, I think the problem can exist either way depending on how they are set up.

Id guess single Glort but I'm not sure. I saw a smaller generator for sale locally it's got thee yellow 115v and blue 230v but it's 60hz

https://www.adverts.ie/heavy-machinery/generator/16432361
Title: Re: Voltage drop under load
Post by: BruceM on October 10, 2018, 01:52:45 PM
The shock potential for a neutral/240VAC system is double that of the US split single phase residential hookup.  I'm glad we have only 120VAC (+/-180V peak) to earth.  Also makes my 120VDC system more practical with only 10- 12v batteries.

I suppose the European power connectors may be part of the problem Bob brings up if they don't have a separate safety ground for metal appliance bodies and/or don't have the neutral keyed.  An obvious safety concern you would like to think your electrical code has well covered so the apprentices wiring things don't electrocute too many people.

The common worldwide use of multiple earthed neutrals for secondary distribution ala the US WYE system is a travesty of bad engineering and is the cause of HUGE amounts of AC current flowing through the earth and aquifers.  It causes home ELF magnetic field levels to be 100x higher than it should. (As clearly demonstrated by measurement of residential areas with Delta power and transformer isolation for each home's secondary derived neutral.) The situation is so outrageous that when Zipse queried large groups of electrical engineers, 85% of them believed that he must be wrong about multiple grounding and WYE violation of transformer isolation, as they felt no self respecting engineer would do such a thing in violation of basic good electrical engineering practice.







Title: Re: Voltage drop under load
Post by: EdDee on October 10, 2018, 02:58:06 PM
Hey JD...

Fire it up, isolated from supplying any load, and give us the following readings:

All AC:

Live to Neutral
Neutral to Earth
Earth to Live
Neutral to a clean, exposed piece of the metalwork of the genhead itself
Live to a clean, exposed piece of the metalwork of the genhead itself
Earth to a clean, exposed piece of the metalwork of the genhead itself

I know I am coming in on the ass end here....but humour me if you would....

Regds
Ed
Title: Re: Voltage drop under load
Post by: Johndoh on October 10, 2018, 04:52:19 PM
Hey JD...

Fire it up, isolated from supplying any load, and give us the following readings:

All AC:

Live to Neutral
Neutral to Earth
Earth to Live
Neutral to a clean, exposed piece of the metalwork of the genhead itself
Live to a clean, exposed piece of the metalwork of the genhead itself
Earth to a clean, exposed piece of the metalwork of the genhead itself

I know I am coming in on the ass end here....but humour me if you would....

Regds
Ed

Hi Ed
The results are....

Live to Neutral - 234
Neutral to Earth - 282
Earth to Live - 391
Neutral to a clean, exposed piece of the metalwork of the genhead itself - 282
Live to a clean, exposed piece of the metalwork of the genhead itself - 104
Earth to a clean, exposed piece of the metalwork of the genhead itself - 0

I did these by using the positive lead on the multimeter to the 1st part and the negative to the second eg red to earth and black to the exposed metal, was this correct?

|thanks
Paul
Title: Re: Voltage drop under load
Post by: glort on October 10, 2018, 11:02:32 PM

You did it right mate. Wouldn't matter which way you did it though with AC.

Unfortunately, You have problems.
Title: Re: Voltage drop under load
Post by: Johndoh on October 11, 2018, 12:44:52 AM

You did it right mate. Wouldn't matter which way you did it though with AC.

Unfortunately, You have problems.

Could you enlighten me please?
Title: Re: Voltage drop under load
Post by: glort on October 11, 2018, 05:18:20 AM

You did it right mate. Wouldn't matter which way you did it though with AC.

Unfortunately, You have problems.

Could you enlighten me please?

Proabably not.
A bit over my head and  I don't know if your system is the same as what we have here or something different.
Either way, I'm pretty sure you should not have the results you are seeing. The more informed will probably educate us both.
To the best of my knowledge you should only get a couple of volts at most going neutral to earth.  The fact you are getting more neutral to earth than live to earth and the same back to the head I think  indicates something is wired backwards somewhere.  Could also be I think the Neutral is bridged to earth which is also not good.

If I were you, once the problems have been rectified I'd be putting a separate Ground on the gen frame so if anything does ever go hot, you are protected.

 I'm pretty sure corrections are needed by an expert.  last thing you want is to let the magic smoke out of yourself.
Title: Re: Voltage drop under load
Post by: Johndoh on October 11, 2018, 08:15:55 AM
Bugger I was afraid you were going to say something like that. The problem for me now is that I know nothing about wires and wiring. The machine was very cheap but anyone around here that knows how to fix it would be very expensive! I'll see what the people on here say about it if it's unsafe I cant use it nor would I sell it to someone else if unsafe.
Title: Re: Voltage drop under load
Post by: glort on October 11, 2018, 08:24:35 AM

It's most likley to be wires in the wrong position.  Easy to fix if you have an idea and are in front of the machine.  Bit more difficult when you are not.
I would think a competent electrician should be able to fix it, especially one whom has had experience with industrial applications.
Motor and gennys can be wired  often in 2 ways, Wye and Delta.  It could just be the genny you have has the output leads hooked together in the wrong pattern as it were. Still not sure that explains the variations but..... again i'm not in front of the thing to see how many wires are coming out of it or how they are hooked up.

Seems Ed was onto and suspected something straight off so will no doubt be able to shed some of his normally insightful light onto things.

Don't panic yet! Could be something real simple, easy and cheap to fix.
Title: Re: Voltage drop under load
Post by: EdDee on October 11, 2018, 08:46:58 AM
Hi Paul...

Going from this:
Live to Neutral - 234
Neutral to Earth - 282
Earth to Live - 391
Neutral to a clean, exposed piece of the metalwork of the genhead itself - 282
Live to a clean, exposed piece of the metalwork of the genhead itself - 104
Earth to a clean, exposed piece of the metalwork of the genhead itself - 0

I would say there is a possibility that the unit has been wired with the actual Neutral bonded to the Earth of the machine, not an uncommon practice and still done today in lightning prone areas.

So, if we assume that neutral and earth are the same here -
1) Your existing "Live" you measured would be a 240V output, it's a little high, 20% high, but there might be an adjustment to lower it.

2)The "Neutral" you measured would actually be a 110V output, a little low, but usable

3)Going by what I have seen in the past with "adjustments" being made, probably this unit was used in a 110V role... the output was a bit low, an adjustment was made, nothing changed(on that 110V output anyway) and the adjustment wasn't returned to previous position/setting...hence the 280v output on the 240V line...It wasn't used at the time, so why bother...

Right - Where to now? - Look for someone who can confirm this and poke around inside the thing... It's not advisable to push 280V to a 240V system - things could get a tad toasty.... or, take a chance and load the 280V line a bit (Neutral and Earth would be the Chassis of the unit, the Live would be what you had measured as a "Neutral" previously... See if the voltage stabilizes at around the 220-240 mark.... If your meter has a frequency measurement, see what the actual frequency of the output is, sometimes running the genhead a little too fast causes problems in interesting ways...(particularly with RMS voltage measurement on cheaper voltmeters)...

Long and the short of it is that its not safely saleable as is, not safely usable as is, its stuffed, if the smoke escapes while paying school fees, nothing lost! If it works to spec when you are finished - it a WIN!

Cheers
Ed

Edit: A bit of an afterthought.... Simple and easy... Put a good old 60W incandescent light bulb between your existing Earth/Neutral and fire it up with nothing else connected... If the bulb lights up, problem, measure the voltage... if not, measure from earth to neutral anyway with it connected... come back to us with your reading....
Title: Re: Voltage drop under load
Post by: Johndoh on October 11, 2018, 09:30:05 AM
Thanks Ed I will go get a bulb this morning we use low energy bulbs now so I have to get one from the shops.

Anyone that would do house calls to look at a generator would want more than it cost. It's a heavy thing to be moving and to be honest when you leave in in with someone you either pay or let them keep it.  I thought getting 230 odd volts ac was all it had to do. When I got this generator my original idea was to junk the alternator and get a new capacitor alternator however the AVR was very appealing. There are 4 wires coming to the control panel from the alternator but I have no clue which is which.
Title: Re: Voltage drop under load
Post by: ajaffa1 on October 11, 2018, 11:19:02 AM
Hey Johndoh, looks like this unit may have been tampered with to customize it for some unknown application. Do you have any history which could help with diagnosis? For example is it ex-military, was it used for agriculture or telecom/hospital back up.

Some photos of the insides would be very helpful.

Bob
Title: Re: Voltage drop under load
Post by: glort on October 11, 2018, 12:08:44 PM

Anyone that would do house calls to look at a generator would want more than it cost.

Might pay to ring around and see. Sometimes things can be cheaper than you think.
  If they could put it in order, it's probably a lot cheaper than getting another head and mucking around with that.

Clearly the thing works, most likley the wiring just needs sorting.  Gen heads can have 12 wires coming out of them. They need to be set up right. If they are not you get problems like this.  Undo them, put them in the right positions and all is fine and good with the world.
Should not take a knowledgeable person long especially if you can find a schematic of the thing and have that for them to refer to.

I would be cautious about touching the thing when it was running and try to bond it to it's own earth to the frame just in case.
Title: Re: Voltage drop under load
Post by: Johndoh on October 11, 2018, 12:27:07 PM

Anyone that would do house calls to look at a generator would want more than it cost.

Might pay to ring around and see. Sometimes things can be cheaper than you think.
  If they could put it in order, it's probably a lot cheaper than getting another head and mucking around with that.

Clearly the thing works, most likley the wiring just needs sorting.  Gen heads can have 12 wires coming out of them. They need to be set up right. If they are not you get problems like this.  Undo them, put them in the right positions and all is fine and good with the world.
Should not take a knowledgeable person long especially if you can find a schematic of the thing and have that for them to refer to.

I would be cautious about touching the thing when it was running and try to bond it to it's own earth to the frame just in case.

I paid 50 for it Glort nearly  all the stuff I bought were related to the engine eg starter new exhaust kill switch etc. It's no longer safe and we have a storm coming well fcuk all that! The nearest guy that repairs generators is about 9 miles away next that I know of is in Dublin which is 40 miles away neither would commit to coming out to view it.

The generator was just in a shed for backup ajaffa nothing too exciting was done with it. I did read somewhere that a generator has a "floating" earth and that neutral and earth should be connected but thats not helping with the neutral having power.

Bob I got a bulb forgot to get a bulb holder I'll have to dismantle one of the bedside lights in the spare room and do it quietly!
Title: Re: Voltage drop under load
Post by: Johndoh on October 11, 2018, 12:49:12 PM
Hi Paul...

Going from this:
Live to Neutral - 234
Neutral to Earth - 282
Earth to Live - 391
Neutral to a clean, exposed piece of the metalwork of the genhead itself - 282
Live to a clean, exposed piece of the metalwork of the genhead itself - 104
Earth to a clean, exposed piece of the metalwork of the genhead itself - 0

I would say there is a possibility that the unit has been wired with the actual Neutral bonded to the Earth of the machine, not an uncommon practice and still done today in lightning prone areas.

So, if we assume that neutral and earth are the same here -
1) Your existing "Live" you measured would be a 240V output, it's a little high, 20% high, but there might be an adjustment to lower it.

2)The "Neutral" you measured would actually be a 110V output, a little low, but usable

3)Going by what I have seen in the past with "adjustments" being made, probably this unit was used in a 110V role... the output was a bit low, an adjustment was made, nothing changed(on that 110V output anyway) and the adjustment wasn't returned to previous position/setting...hence the 280v output on the 240V line...It wasn't used at the time, so why bother...

Right - Where to now? - Look for someone who can confirm this and poke around inside the thing... It's not advisable to push 280V to a 240V system - things could get a tad toasty.... or, take a chance and load the 280V line a bit (Neutral and Earth would be the Chassis of the unit, the Live would be what you had measured as a "Neutral" previously... See if the voltage stabilizes at around the 220-240 mark.... If your meter has a frequency measurement, see what the actual frequency of the output is, sometimes running the genhead a little too fast causes problems in interesting ways...(particularly with RMS voltage measurement on cheaper voltmeters)...

Long and the short of it is that its not safely saleable as is, not safely usable as is, its stuffed, if the smoke escapes while paying school fees, nothing lost! If it works to spec when you are finished - it a WIN!

Cheers
Ed

Edit: A bit of an afterthought.... Simple and easy... Put a good old 60W incandescent light bulb between your existing Earth/Neutral and fire it up with nothing else connected... If the bulb lights up, problem, measure the voltage... if not, measure from earth to neutral anyway with it connected... come back to us with your reading....

Hi Ed

Connected a small lamp to neutral and earth, bulb didn't light but voltage became very unsteady going between 50 and 300 volts. This was also showing as fluctuating on the analogue dial on the generator. I ran the generator a few weeks ago during a power cut and everything seemed to work ok apart from the well pump but that was traced to 40 feet of coiled wire.
Paul
Title: Re: Voltage drop under load
Post by: EdDee on October 11, 2018, 02:09:34 PM
Hi JD...

I think I know what is wrong....

If its a Yanmar close coupled to a chinesium genhead (a la the pic that you referred to via this link:
( https://www.ebay.com/itm/Yanmar-6KW-Diesel-Generator/183384598167?hash=item2ab292e697:g:pBIAAOSw-mdbdzYO )

Pull the AVR off the back of the genhead and take a look to make sure that the heatsink on the back of the AVR isn't touching earth.... The chinesium replacements I got for my genhead had the heatsinks a little to proud and not insulated from the bits inside the epoxy either... Caused a "ground loop" when I connected the gennie to the house, power cycled, regulation went for a ball of sh!t, weird readings on chassis/earth pin, live and neutral.... If it ran stand-alone, it was fine...regulation perfect, all smiles...

Problems only showed up when I connected it to the house, which has a bonded E/N at the db board....

I put a spacer in to lift the AVR away from the genhead, all problems sorted!

Ed

Edit: <Quote:>Connected a small lamp to neutral and earth, bulb didn't light but voltage became very unsteady going between 50 and 300 volts. This was also showing as fluctuating on the analogue dial on the generator. I ran the generator a few weeks ago during a power cut and everything seemed to work ok apart from the well pump but that was traced to 40 feet of coiled wire.<Unquote> -

If its the heatsink shorting, the coil of wire caused enough "transformer effect" to feed back onto the Earth line of the lead, entering the regulator via the heatsink, stuffing up the regulation on the AVR... Once you have checked that spacing on the AVR and if you found it looped to ground, plug in your 3000' coiled lead and all should be well....
Title: Re: Voltage drop under load
Post by: Johndoh on October 11, 2018, 07:03:56 PM
Hi Ed

This was originally a silent enclosed generator the avr is mounted on the frame of the generator not on the head its self. I have a spare avr chinese made I will try it tomorrow. I suppose it could be that its race is run!
Title: Re: Voltage drop under load
Post by: EdDee on October 11, 2018, 08:55:49 PM
Hey Jd,

Check for that little heatsink on the back of the avr sorting to frame ground... Unbolt the avr and let it hang loose if you need to, then do the lightbulb between n-e test again...

I don't think the avr is buggered....not yet anyways....

Ed
Title: Re: Voltage drop under load
Post by: Johndoh on October 11, 2018, 09:01:32 PM
Hey Jd,

Check for that little heatsink on the back of the avr sorting to frame ground... Unbolt the avr and let it hang loose if you need to, then do the lightbulb between n-e test again...

I don't think the avr is buggered....not yet anyways....

Ed

Avr isnt touching anything its on a little piece of sprung steel. It was probably made in china too so it could be dodgy?
Title: Re: Voltage drop under load
Post by: glort on October 12, 2018, 01:15:54 AM

If the steel is mounted to the engine or another piece of metal, take it off.
It could still be grounding.
Title: Re: Voltage drop under load
Post by: ajaffa1 on October 12, 2018, 09:46:53 AM
Hi JD. just to emphasis the issue, here is a photo of a standard Chinese AVR, please note the warning on the hearsink, It`s live when running!  :o

Do you know if your generator was originally built with an AVR or was it fitted later? If it was retro fitted, you can probably remove it all together and see how it goes just running with the original rectifier. Won`t be anywhere near as smooth an output but it should identify if the problem lies with the AVR.

Bob
Title: Re: Voltage drop under load
Post by: glort on October 12, 2018, 10:40:23 AM

I have a couple of these AVR's sitting in the Cupboard with my electronic component pile.
They were given to me by someone who bought them against me repeated advise and then discovered they weren't the problem.... as I had told them repeatedly.  :laugh:

Often wondered what other useful application I could put them to?
They would seem to have a level of control ability but I haven't found a way to adapt them to an Imag or anything else yet.
They seem nice units just begging for the DIY tinkerers misappropriation for a beneficial use.
Title: Re: Voltage drop under load
Post by: Johndoh on October 12, 2018, 12:11:23 PM
The AVR is like this one

https://www.ebay.co.uk/itm/AVR-Automatic-Voltage-Regulator-For-Generator-6-5KW-7KW-8-5KW-High-Quality/312241462391?epid=13010033303&hash=item48b30a9c77:g:WAIAAOSwi3tbIsqe:rk:26:pf:0
Title: Re: Voltage drop under load
Post by: EdDee on October 12, 2018, 01:06:25 PM
Hi Bob,

Those little genheads wont put out any real power without the AVR, the 6 wire units have 2 inputs for supply, 2 inputs for sensing and 2 outputs to the slip rings - You can cobble a small dc supply together and feed the slip rings thereby getting output, but a right PITA to regulate under a varying load....been there!!

Cheers
Ed

(PS - Also "been there" regarding the heatsink shorted to earth....kept me running around looking at just about everything else before I tracked my induced fault down!!)
Title: Re: Voltage drop under load
Post by: Johndoh on October 12, 2018, 01:44:31 PM
I Noticed, there's a couple of guys selling cheap generators that have been used for electro fishing. I have no idea what this is but the ads all say the generators could be modified for normal use. I got to thinking, is this what I have???
Title: Re: Voltage drop under load
Post by: EdDee on October 12, 2018, 02:04:17 PM
No, I don't think it is what you have....possible, but unlikely....I still think you have a genhead of similar nature to mine with a fault that came about after someone, at some stage, replaced the AVR....Have you unbolted the AVR and checked yet?
Title: Re: Voltage drop under load
Post by: Johndoh on October 15, 2018, 11:02:40 PM
At last my new voltmeter has arrived! I plugged it into the house it showed 50.7 HZ I then plugged it into the generator and it's showing 57 HZ @ 3000 rpm, what should I do next??
Title: Re: Voltage drop under load
Post by: EdDee on October 15, 2018, 11:10:21 PM
Frequency measurement at the generator outlet is a bit hit and miss... there are quite a few stray magnetic fields and some minor harmonics on the lines up close... trust the frequency reading only when you have a bit of a load on it and you measure it 'at a distance' ...

Have you pulled the AVR off it's mounting plate yet to check for that suspected short?

Cheers
Ed
Title: Re: Voltage drop under load
Post by: Johndoh on October 15, 2018, 11:15:19 PM
Frequency measurement at the generator outlet is a bit hit and miss... there are quite a few stray magnetic fields and some minor harmonics on the lines up close... trust the frequency reading only when you have a bit of a load on it and you measure it 'at a distance' ...

Have you pulled the AVR off it's mounting plate yet to check for that suspected short?

Cheers
Ed

Hi Ed
I didn't do anything to it since. I will take a look tomorrow when I load it up to check frequency. Should I run an earth lead from the alternator to my earth stakes?

Paul
Title: Re: Voltage drop under load
Post by: EdDee on October 15, 2018, 11:38:40 PM
Hi Paul,

Take care when working on it while it is running... Personally, I wouldn't earth it, for fear of a feedback loop and blowing the AVR, but that does present the possibility of 'shock hazard' if you touch ground and gen frame at the same time.

In this case, I would use utmost care, de-mount the AVR, install the small globe between N-E, then start it up... if the power fluctuates as before, shut it down immediately... Without touching metal on the gen if at all possible.. Dry leather glove or a good rubber glove recommended... The chances of killing yourself are slim, but hey, why take a chance if you are not familiar with the angry pixies...they might try and bite you!

If the power fluctuates with the AVR unbolted from the plate, I think you will need a pro to come take a gander... If the voltage is stable, we have found the problem....

Also, when you unmount the AVR for the test, stick it in a plastic container or something to insulate it and prevent it from touching other metalwork and  shorting out on something else...

Further, if this solves the problem, don't expect the 'AVR in a plastic box trick' to be a solution long term... it will need proper mounting without being enclosed for cooling...

Cheers
Ed
Title: Re: Voltage drop under load
Post by: glort on October 16, 2018, 02:00:07 AM

I would also suggest if unmounting the AVR does not fix the problem, it may be worth buying another one and fitting that to test it. They are available for about $20 here so not expensive but it seems where Paul is things are a lot more pricey in freight if not the component itself.

The AVR could also be remotely mounted, say on a Control box with just the wiring extended.  I'd isolate that if it were in a metal box as well, wood one would be perfect, and if need be a small fan could be directed to blow on it.
I have a fan on my main inverter with a little temp switch running through a relay. When the inverter gets to 40C, the fan turns on blowing air down the back along the heat sink.  Electronics do not like heat and the cooler you keep them the happier they are.
Title: Re: Voltage drop under load
Post by: Johndoh on October 16, 2018, 01:32:35 PM
Ok guys here's an update report. I had a spare AVR the black one in the link, unused from the land of "please be understanding" it wouldn't adjust, started at 280 volts ended 280 volts thats crap. I only just got the votmeter so I connected up the old AVR and played with it for a while. Turns out the frequency is better than the house by .5%. I did the other tests again and they are a little interesting in that they power is one way so red probe to neutral and black to earth shows voltage reversed they dont same with live to earth. live and neutral shows voltage and minus voltage. I touched it when it was running and lived!

Here is a link to the photographs https://www.dropbox.com/sh/h0ety3ppwht4wsm/AAAokl9kwbM1USKcSwwl2LvIa?dl=0

FG Wilson on generator earthing http://www.fgwilson.ie/files/generator-set-neutral-earthing.pdf
Title: Re: Voltage drop under load
Post by: EdDee on October 16, 2018, 01:56:02 PM
And with the AVR unbolted from the frame, in an electrically insulated position, with the light globe between N-E?

...

..

.

?

Edit: Incidentally, on some of the older Yanmar gens I have worked on, the older metal cased AVR's had to be insulated from ground - They were originally mounted on two insulated posts on the rear of the genhead. (Hence the crescent shape.) The "modern" chinesium replacements are "potted" with only the little heatsink tab on the back needing to be insulated from electrical contact to ground, but its a crap shoot as to whether you get one with the wiring done correctly. The new ones often have the 2 Blue and 2 Yellow wires (Sense and Supply) in the 4 contact block switched around. They are not polarity/phase sensitive from what I can make out....
Title: Re: Voltage drop under load
Post by: Johndoh on October 16, 2018, 02:33:35 PM
The AVR is in a small plastic tub. The bulb doesnt light connected neutral to earth
Title: Re: Voltage drop under load
Post by: EdDee on October 16, 2018, 02:43:14 PM
Is the output steady and not varying?

What is the N-E voltage now?

Ed
Title: Re: Voltage drop under load
Post by: Johndoh on October 16, 2018, 02:48:23 PM
Hi Ed

The neutral earth voltage is 272 volts When I connect the lamp it slowly drops to less than 200 from 235 ish

thanks

Paul
Title: Re: Voltage drop under load
Post by: EdDee on October 16, 2018, 02:51:40 PM
And the lamp isn't lit?

Is the output steady(around the 230V area)?

Send pic of the meter screen when its at the "less than 200" mark....(I suspect that the meter has autoranged down to millivolts maybe)

Ed
Title: Re: Voltage drop under load
Post by: Johndoh on October 16, 2018, 03:29:57 PM
Hi Ed

No the lamp doesnt light. Running the meter shows mid 230 volts and about 30 volts with the power off at the generator panel. Plug the lamp in its showing 104 volts powered off at the switch and 240 volts on the control panel. Turn on the lamp and the voltage drops and rises, fluctuates, needle swings about on the control panel.

Paul
Title: Re: Voltage drop under load
Post by: EdDee on October 16, 2018, 04:06:46 PM
Confirm - The AVR is still in the plastic tub and not touching ground anywhere with the above readings?
Title: Re: Voltage drop under load
Post by: Johndoh on October 16, 2018, 05:15:08 PM
Yes its totally isolated Ed

P
Title: Re: Voltage drop under load
Post by: EdDee on October 16, 2018, 10:24:40 PM
Hi Paul,

At this point I think you should call in an onsite pair of experienced eyes to take a look see for leaky insulation on the armature/rotor... This type of problem can occur if the unit has been used in a damp environment, particularly where there is salinity present. There appears to be a feedback onto the regulator circuit, most often caused by the things we have checked as above, but also possible if there is an insulation breakdown in both the fields and the rotor - stray voltages are presenting themselves to earth (probably from the fields) and being picked up by the AVR when N-E are tied, even by a fairly high resistance such as a light globe. Under "normal" conditions, the N-E can be linked without any form of influence to output, but, in the case of leakage to/from the rotor windings to/from the field windings, problems with output regulation by the AVR can occur....

About the last thing you could check, would be the wiring to and from the windings and brushes, look for any trapped wires that may be pinched and shorting to earth. All of the next lot of tests would require you to check for shorts or resistive links from the windings to earth. Whilst you have the bare requirements in the line of a digital test meter to do it, you might need to spend a bit of time at "Google University" to see how its done.

Pretty much, in a nutshell, you disconnect all the terminals on the alternator, unplug the AVR, unplug  any charging regulators and start looking for any resistance readings between each terminal and ground on the alternator.... Depending where the leak is found, that determines the course of action from there on.

Sorry that we coudn't nip this problem a bit earlier in the convo! Persevere and try and get it going to spec... that's a lovely little genset you have there and certainly worth investing a bit more time into!

I have a similar unit, its now 2 or 3 real beaut lightning strikes old... I have rebuilt it each time, the first took out the auto start switchgear, the second took out the auto changover circuitry, the third fried the genhead totally.... So its almost new now!! (Each bit was fabricobbled and re-inforced with something bigger and better at replacement!)  About the only original bits are the frame, covers, tank and engine!!

I can assure you, I would not have rebuilt mine each time would it not have been worthwhile!

Good luck!!

Cheers
Ed
Title: Re: Voltage drop under load
Post by: Johndoh on October 16, 2018, 11:40:33 PM
Hi Ed

When I was doing the little tests today I had a look at the wires to check if something obviously wrong was visible. I noticed that the insulation on some of the wires disappearing into the alternator is cracked. Thats enough for me to stop using it. So what to do?
I'd have to pay someone to bring it off to get tested thats a minimum of 150 and it needs repairs even I know that. I could sell it as spares or repair but I'd feel I had to damage something (cut a wire maybe) so it was inoperative but what? If someone repaired the part I damaged they would still have a dangerous generator. The other thing I am considering is a new Mecc Alte brushless alternator. This would be in the region of 400.00 it would be new, safe, hopefully reliable etc. If it was sold Id get a few quid for it because of the engine but where do I go to get another diesel engine for 50?

http://www.ryalls.ie/used-tractor-machinery?skupeUrl=BC%3D3%26displayContact%3Dfalse%26NI%3D19716020%26PN%3D1%26RPP%3D10%26CN%3D3%26UI%3D513193%26SF%3D999999%26SA%3Dtrue
Title: Re: Voltage drop under load
Post by: glort on October 17, 2018, 01:56:59 AM

I'm still not even sure what the engine you have actually is?

Do you have a Yanmar Horozontal Cylinder type or a China Vertical?

What is the situation with these in ireland?  Are you allowed to bring them in, are there many around?
Title: Re: Voltage drop under load
Post by: Johndoh on October 17, 2018, 07:18:46 AM
Its supposed to be a yanmar it's a 10 hp vertical. There's no restriction on buying these type of engines here except price, they aren't cheap. It' starts on half a turn or on the first pull, its noisy but all those little high speed engines are noisy. I bought it mostly for the engine. Ed was on the money about this and I'm grateful for the input from you guys it could have ended badly! When I finally figured out how to use the multimeter I was surprised at how stable the frequency was so a new alternator makes sense right now, you never know a different generator with a fcuked engine could come along!
Title: Re: Voltage drop under load
Post by: EdDee on October 17, 2018, 09:13:15 AM
Hi JD,

On my last rebuild of my unit, I manged to get a scrapped 6KVa petrol screamer with a "leg out of bed" .... Pulled the alt and fitted it to the Yanmar.... Problems solved!

Was the cheapest and easiest solution at the time.... Used the tank as an extra for my Lister, Frame became something else, engine I chopped up and smelted...except for the crank, which I machined big end off, mounted it in the 1/2 of the crankcase, fitted a pulley where the big end was, mated another small alt to the other side and gave it to a mate as a belted alternator...

Your best bet is to spend 5 quid and get an obviously poked oil pisser that nobody wants.... The Alts on a mechanically buggered unit would generally be ok to re-use.... People seem to think that when the engine's inside's have become outside's the alt is worth nothing....not true!

Cheers
Ed
Title: Re: Voltage drop under load
Post by: mike90045 on October 17, 2018, 05:38:55 PM
from the grounding PDF :   the high voltage winding (earthed through a neutral resistor).

I'm pretty sure that's not the english I speak, earthing through a neutral resistor ?
Title: Re: Voltage drop under load
Post by: Johndoh on October 19, 2018, 07:21:39 PM
Little update - my brother brought me to a collector of stuff he had a chinese generator that seized. 40.00 changed hands and I came home with a brushless alternator. The capacitor lugs got broken on the trip home. Anyhoo it's connected and making power but only 200 volts. I want to replace the capacitor but there's no markings on it. Apart from the buy and try method is there any way to determine the uf rating on these. ?
Thanks
Title: Re: Voltage drop under load
Post by: BruceM on October 19, 2018, 10:27:13 PM
The cheapest capacitor meter will work just fine.
Title: Re: Voltage drop under load
Post by: Johndoh on October 19, 2018, 10:48:27 PM
Thanks mate the meter is my new toy and obviously as a man I didnt NEED to read the instruction manual. I have worked out that the capacitor is 36uf so im thinking 40 would increase the voltage slightly? I was also thinking of adding 150 rpm any other suggestions welcome
Title: Re: Voltage drop under load
Post by: BruceM on October 19, 2018, 11:40:51 PM
I'm not familiar with capacitor regulated alternator designs, but hopefully someone else is and can help you.

Title: Re: Voltage drop under load
Post by: mike90045 on October 20, 2018, 12:19:46 AM
>  is there any way to determine the uf rating on these

Capacitor meters.  Been around for years, and they should be more than enough to measure the cap.

Just remember, it may leave a charge on the cap, which can "bite" - sometimes fately .  Be careful.
Title: Re: Voltage drop under load
Post by: Johndoh on October 20, 2018, 12:25:14 AM
>  is there any way to determine the uf rating on these

Capacitor meters.  Been around for years, and they should be more than enough to measure the cap.

Just remember, it may leave a charge on the cap, which can "bite" - sometimes fately .  Be careful.

hi Mike
I figured out how to use the meter its says 36uf the voltage is a little low at 200 volts. The alternator has been sitting for a while maybe the capacitor needs a bit of work? maybe its goosed? I was going to speed up the engine by 150 rpm but i might lose the frequency ???
Paul
Title: Re: Voltage drop under load
Post by: glort on October 20, 2018, 01:40:12 AM
Thanks mate the meter is my new toy and obviously as a man I didnt NEED to read the instruction manual.

Well done mate! We need more real men in the world who stand by the time honoured practices of " The shed" and the traditions of our forefathers.
Instructions and manuals are an option of last resort only. How is anyone going to learn if they don't waste an hour figuring out all the wrong ways of doing something if they just do it right in the beginning by spending 5 Minutes reading the instructions in the first place! Just not the done thing!
Wouldn't catch me doing that, I do it the proper way, only ever read the instructions when there is no other possible option and THEN Figure which button I should have pushed in the first place!  :0)

Quote
I have worked out that the capacitor is 36uf so im thinking 40 would increase the voltage slightly? I was also thinking of adding 150 rpm any other suggestions welcome

Capacitors are not finite.  They work in ranges with a nominal value.  You could get a 40Uf cap and measure it and it would be 36 Uf .... or maybe 42.
Have you measured the frequency as yet?  Maybe the engine is turning slow anyhow?  I'd check that first to make sure it just doesen't need turning up a tad.  I remember the first ( new) genny I ever bought. the thing was miles out.  I ran it for a couple of hours at half load to break it in a bit then re set the engine speed. Haven't adjusted it since. Always spot on now.

See where that is first and then look at bumping the cap. If the head is older the cap might have dried up a bit and is lazy. You may be better off to buy a new one of the right value then if it's still low on voltage buy another say 5 UF and add that in.  The value is additive in parallel and subtractive in series.
Small value caps are very cheap anyway and it allows you to fine tune better.

Ideally you want to match the Frequency and the output together.
Title: Re: Voltage drop under load
Post by: Johndoh on October 20, 2018, 08:18:27 AM
Thanks glort. The capacitor fits inside the end cover is it possible to have 2 capacitors mounted outside? I didn't measure the frequency on this it was quite good on the last alternator and I didn't change the engine speed. I have several capacitors from previous experiments so a 20+15 uf wired in parallel could work? If there was a little more power then I can order a new capacitor that fits properly? My lights and TV would work on 200 volts anyway I think? Another question! There is no data label on the alternator is there a way to calculate the total output? The alternator fits on to the engine but it's shorter by over an inch.
Title: Re: Voltage drop under load
Post by: glort on October 20, 2018, 01:25:43 PM

You can mount the caps anywhere you like. If this is a stationary setup in a shed, you can run leads from the gen head up to the control panel.... which isn't a bad way of doing things as it eliminates the heat and vibration of the engine on the caps for a start. With my induction motor generator, I had a setup where I could switch in more caps as needed to balance the load. You wouldn't need that but remotely mounting would be a good thing.

You could try the caps you have and see what the voltage is. If it comes up then yeah, buy a new one.
Also try adding all 3 caps caps together. If you put the 20 and 15 in SERIES that would give you about 8 Uf and then PARALLEL that to the one you have and you would have a total of 44 Uf. You could then see if that brought the Voltage up.

I'd still check the frequency though just in case something has changed.

As for calculating output, that is something outside my knowledge limitations. If the alt has a model number you could look it up that way.  Also do you know what the old engine size was that was driving it and the make of genny? You could match them up as well.
Title: Re: Voltage drop under load
Post by: Johndoh on October 20, 2018, 05:13:04 PM
Hey Glort
Again many thanks for your wise and useful input. These are the readings I'm getting with a 25 uf & 20 uf capacitor wired in parallel. The voltage does fluctuate by 2 or 3 volts but I'm happy with what it is for small money.  Photos attached.
Title: Re: Voltage drop under load
Post by: glort on October 21, 2018, 01:21:03 AM

You gained 25V with 45 UF over the 200V you got with the original Cap?  Good result!

Is the 50V reading off the exciter winding?  That seems about right.  Hopefully it's not off the neutral side.  :0)

Fluctuations are normal. I don't know if it is the voltage or just the way the meters measure but it's very rare to get a rock steady Voltage on AC in my experience.  Even the mains power moves constantly here.
Title: Re: Voltage drop under load
Post by: Johndoh on October 21, 2018, 08:55:29 AM
thats 50 HZ mate
Title: Re: Voltage drop under load
Post by: glort on October 21, 2018, 10:08:25 AM
thats 50 HZ mate

Hahahah  DUHH!

Yeah, Ok, that one went straight through to the keeper!   :embarassed:

Well frequency as you predicted is not a problem and volts are close enough.
What is your actual spec there? Is it 230 or 240?  Ours was 240 but they brought is back to 230 some years back now.  A lot of appliances sold here actually have 220 on the tag which I think is for the US market with their 3 phase or whatever their high voltage output is.
Std 3 phase here is 415V.
Title: Re: Voltage drop under load
Post by: Johndoh on October 21, 2018, 10:37:35 AM
We have a nominal 230v power here. A lot of the electrical stuff comes from the UK and they use 240v -6% to +10%. The system of  230V +/-10% that is used in Ireland is pretty much the same. It was something to do with harmonising power supply across Europe. Usually only businesses here have 3 phase 415 volts supply. I have to do some tidying of wires today get it earthed and so on. I was going to speed up the engine to 3600 with the original capacitor to see if it was designed to run at a higher speed but then the frequency would be off. There should be a 5uf capacitor somewhere I could add but I think its ok as is. The cheapness appeals to me as well!
Title: Re: Voltage drop under load
Post by: glort on October 21, 2018, 01:32:10 PM

I wouldn't be touching engine speed. Frequency aside that extra 600 revs makes a fair bit of difference to engine life and wear.
You are around 2% of tolerance now so pretty good. You could try adding the 5uf and see where that goes.

I always prefer volts a little on the high side if possible but the margin is pretty wide in reality.



Title: Re: Voltage drop under load
Post by: EdDee on October 21, 2018, 10:38:22 PM
For my need it in a hurry with max output gennies, I set rpm to between 60 to 63hz, volts to 240... These are the little portables that I lug round the plot to do the odd bit of electrical needed in a remote corner type work... they seldom run more than an hour or two at a time, but are run hard...

The bigger, less portable standby units, I normally clock to 51hz unloaded, 230V, and they run at a lower percentage of total output, but much, much longer periods....

Both ways they seem to last well... but to run hot and fast and heavy for long ain't a good idea in my book....

Cheers
Ed
Title: Re: Voltage drop under load
Post by: Johndoh on October 21, 2018, 10:45:56 PM
For my need it in a hurry with max output gennies, I set rpm to between 60 to 63hz, volts to 240... These are the little portables that I lug round the plot to do the odd bit of electrical needed in a remote corner type work... they seldom run more than an hour or two at a time, but are run hard...

The bigger, less portable standby units, I normally clock to 51hz unloaded, 230V, and they run at a lower percentage of total output, but much, much longer periods....

Both ways they seem to last well... but to run hot and fast and heavy for long ain't a good idea in my book....

Cheers
Ed
Hi Ed
Thanks for the info all this stuff is stored for future reference, I will speed it up slightly tomorrow only need 60 more rpm. Power was off for an hour this evening and I ran a few lights and the television off it, wife didn't complain about flicker either. Now a question Ed do you know how I could find out the total output of the alternator using a multi-meter?
Thanks
Paul
Title: Re: Voltage drop under load
Post by: EdDee on October 23, 2018, 12:56:09 PM
Hey JD,

Not easy.... Need 2... one measuring current, the other voltage....Multiply the readings to get VA.... add up your totals every second or two, do it for an hour, you get KWH ....

Or....

Buy a cheapie VA meter off fleabay and throw away the pencil!

Cheers
Ed
Title: Re: Voltage drop under load
Post by: glort on October 23, 2018, 02:19:42 PM

Buy a cheapie VA meter off fleabay and throw away the pencil!

How would you do it that way Ed?
Just load the thing up to overload and read off the max output?
Title: Re: Voltage drop under load
Post by: EdDee on October 23, 2018, 03:41:24 PM
Yep, that's pretty much it.... Load to start of black, make note of V/A/Kw.... Load to start of blue, note same..... A quick look at the exhaust emissions from a distance tells you approx how hard its running....except at night.....then you can only tell if its running hard if the exhaust glows orange....

Lol
Ed
Title: Re: Voltage drop under load
Post by: glort on October 24, 2018, 02:05:07 AM

One of these Meters Ed suggests Paul would be handy on your control box anyway. I have several of them.

there are a couple of types, the ones that are relatively low current that run direct through the meter and the others which take up to 100A I think it is and have an inductive pickup you put round one lead.  I was looking at one of mine this morning.  Inverter reported wattage was 27W different to the meter on a 3.6 Kw output. better than 1% is good enough for me but for all I know, the meter could have been more accurate than the inverter. 

Another hand feature of the things is to see how much power in total you have used.  this is very handy for my solar because not all my old inverters have this feature and some re set once the sun sets so if I'm a bit late because it's cloudy or something, I don't know how much power that unit made for the day. Not that many people would worry but like I said, I have no life so have time to pay attention to these things!  :0)

These are the ones to get:

https://www.ebay.com.au/itm/AC-80-260V-LCD-Digital-0-100A-Volt-Watt-Power-Meter-Ammeter-Voltmeter-CT/262893099112?hash=item3d35a65868:g:lk8AAOSwTM5YxmA4:rk:4:pf:1&frcectupt=true

Bought a lot of stuff off that seller and found them to be very good and reliable as well as being the cheapest if not only cents away from being the cheapest.
You can remote mount the sensor as well by just extending the leads and running them back to the meter.  Note, you only run ONE wire through the middle of the sensor and there is no electrical connection which is a good feature.  I have a couple of these set up in a jiffy box that I can just plug in to different things and see what they are doing. the logging feature of power used is handy to see how much power the Fridge or the heater in the biogas digester is pulling per day as well as the instant draw.  You can also see how heavy the current different things like water heaters are pulling or how much your solar inverter or generator is pushing back.   :0)

You could also use a clamp meter but these things are generally cheaper and you get more readouts and the logging where you can measure over a period of time. And the batteries don't go flat when you leave them on.... as they are supposed to be.
Title: Re: Voltage drop under load
Post by: Johndoh on October 24, 2018, 09:55:34 AM
Thanks Glort more stuff to think about more toys for me! I was looking at a Robin EY20 generator yesterday needs some work but interesting if I can get it cheap. I know I dont need it but I never had a Robin engine before something to play with over the winter.
Title: Re: Voltage drop under load
Post by: glort on October 24, 2018, 10:25:57 AM

Robins are great engines. Made by Fuji Heavy Industries, AKA Subaru.
Far as petrol Gennys go, these would be a top shelf Choice.

Personally I think it's a good idea to have a petrol and a Diesel Genny. Most people have a petrol car or there is one close by and even a 1/4 car tank will power a genny for a good while.  Only thing is if you are not going to use them for a while, drain the carby and the tank and then give them a rinse with some petrol that's had a good amount of 2 stroke or engine put in it to stop any corrosion.
Also drain the sump and refill with fresh oil.

You could also get a gas carby like I linked somewhere recently so you could have the option to run on LPG as well.

We are going to start sounding like a bunch of those goofy preppers soon.  The minute anyone starts talking about "Bug out vehicles" I'll be bugging out of here.
How people think they are just going to cruise down the highway to their bunker or whatever in a dire emergency when in most places an hour trip down the road takes you 3 at holiday time just does my head in. Of course the other side is, you are going to stack your house with Food, water, fuel and have the lights on at night while all the neighbors around you sit in the dark and starve.
From there, if they do come wanting food etc and try to take it, you are going to have a shoot out with them too keep whats yours.

YA!

There's more than one born every minute, there's a whole pile of them and they breed as well!  :o
Title: Re: Voltage drop under load
Post by: Johndoh on October 24, 2018, 11:02:22 AM
Thats splendid news about the Robin. Seller said he put a new carb on it but it needs "adjustment" I checked and new carbs are pretty cheap and readily available. Of course people attempt repairs on things they shouldn't touch so if I get it might be a simple fix. Glort you repaired lawnmowers I sometimes buy them in winter and do them up, its a little source of income. The amount of mowers with the carb gummed up and all the little springs missing on the carburettor linkage is amazing. These simple engines are a big challenge for some people.
Title: Re: Voltage drop under load
Post by: glort on October 24, 2018, 12:44:28 PM

You are dead right there.
I used to really like doing the little engines. To sound cliche, it was like each one had it's own little story when you opened them up.  Some were just worn but appeared cared for, some had been destroyed by people without a clue.
I don't know how many I picked up at the tip, brought them home and with the most minor of " repairs" , ran perfectly.  I got 3 over time that had obviously been rebuilt very recently.  I remember one was missing the sparkplug and very dirty. I used to do them in batches so I washed a load of them down and started tearing into them. I pulled this one apart and when I got into it, I couldn't believe it. I wasn't sure if it had even run but had been fully recoed.
There was still grease in the roller bearings.

Put it back together, put a plug and fuel in it and off it went.  Sold it to a Neighbour whom had the thing 10 years last time I saw it.

On the opposite end there were a few that had been recod not too long before but being 2 strokes, some twit had not put oil in the petrol.  Looking at engines that have welded themselves together  through lack of oil, 2 or 4 stroke is nit a pretty sight.
I mainly did 2 strokes which were a locally made brand because parts were cheap and plentiful and I could tear them down and have them rebuilt in an hour and running again. 

The only 4 strokes here at the time were Hondas that never went wrong and those POS garbage Briggs things.  I hate them with a passion and always will! Cheaply made poor quality CRAP!  We would tear bran new ones down before giving them to contractors and find problems with them. A  real common one was flashing in the castings almost blocking the inlet or exhaust port.  Carb linkages that were out of wack were another one not to mention those horrid " Pulsa jet" and the like carbs which were briggs own nightmare creation.

What morons would  make an engine with aluminium bores and steel piston rings?  Didn't do a lot of them as repairs or rebuilds as they simply were not worth it.  You could literally buy a set of pistons and rings for a 350 Chev cheaper than buy a rebuild kit for a briggs from our supplier.  As mate pointed out, a Piston for a briggs cost more than a set of 6 Pistons for a local brand car.  Crazy.

I liked 2 strokes best but didn't like doing chainsaws. Still don't . Too tight and fiddly for my shrek hands and fingers as my daughter calls them.  My own chainsaw is sitting up the back now and needs the fuel lines replaced. Bought it months ago but been putting the job off. Got the thing out the other day and made a start but took me about 2 min to decide I wasn't in the mood for frustration so it's sitting right in the shed door for me to trip over and be motivated to do it.  Brush cutters were OK, not much to them and they come apart easy.  Did a fair few 2 stroke bikes as well. Mainly Dirt bikes but a few yamaha RD 2 and 350s which were the hot ticket then. Bikes were ok just doing the top end but I didn't like pulling the engines out and mucking wioth everything else. Too complicated for my liking even though I could do it.  Usually forget something and have it all buttoned up then spot one gear or spring sitting on the bench. Aggghhh!  With the top end there was nothing to forget.

When ethanol laced fuel came in here, that was a good revenue raiser for small equipment places.  Sucks the water clean out the air and condenses it in the tank or fuel bowl.   
We'd clean them out, always a blocked main jet and gunk in the float bowl and tell them it was fuel and to use proper stuff not the Ethanol laced  but some listened and happily, a lot did not. They would get miffed about the problem recurring but we'd say how did it go when you picked it up, perfect, then it wasn't a bad repair was it?  They would come back so obviously knew it even if they didn't want to admit it.


I often think of doing those things. I really enjoyed it.  I had my white collar upmarket business which made me heaps of money but I liked doing stuff with my hands, getting filthy and bringing these things back to life.  Often I'd be finished with  clients, take off the shirt jacket and pants and be up the shed covered in grease and crap.  Few hours up there, back inside for a shower and a scrub and back to  being all professional again.  My secretary thought I was nuts. Occasionally Clients would drop in without an appointment and see me in mechanic mode but it was never a problem, in fact I used to say was a great rapport builder with the blokes.  Sometimes I'd just stay there at night and not finish till midnight. I found it relaxing and was nice to be up the back with teh doors open on a warm summer night and summer was obviously the busy time.  The late hour Never stopped me firing anything up for a test run though!

 Smartest thing I ever did was buy another house to run the business from instead of renting a shop.  Had so many upsides it wasn't funny. Had huge garage, just as big a workshop and a great house for the business.  Pool in summer was also great when the kids were young and we could sleep there weekends as well.  We never had a party at home either, always there because it was so much bigger and better for entertaining. 
 Of course the fact i sold it for exactly $1M profit 20 years later wasn't a downside either! 
I made  real good money with my mate doing those mowers and engines which was all in my spare time between clients or just as something to chill out doing. 

That was a real good time in my life.
 I'd give a lot more than a million now to go back to the way things were then.  :(








Title: Re: Voltage drop under load
Post by: ajaffa1 on October 24, 2018, 12:58:21 PM
Hey Glort, there is still money to be made in servicing small engines. There is a company in Hongkong called Farmertek, they make very good reproduction parts for Stihl and Husqvarna machinery. A new cylinder, piston, crankshaft, all the gaskets and etc for a 48 cc chainsaw was under $100 delivered. Replacement chainsaw around $1000

Bob
Title: Re: Voltage drop under load
Post by: Johndoh on October 24, 2018, 01:12:37 PM
I always find myself strangely attracted to Briggs side valve engines! Good Honda lawnmower engines are easy to get probably because the frames are rotten, nobody ever cleans them and they rust from underneath. The engines don't fit the aluminium mower bodies that the Briggs engines fit. My mower is a really old CastelGarden with an old Briggs Quantum side valve engine. It needs valve stem oil seals this last 5 years poor compression and smokey I really have to fix it for next year. It's got the wrong carburettor and cables made from old bicycle brake cables. You'd never see a 2 stroke mower here apart from on a hover mower. I know the Briggs OHV engines are crap so Im now on the hunt for a 5hp Quantum side valve
Title: Re: Voltage drop under load
Post by: glort on October 24, 2018, 01:39:04 PM
A new cylinder, piston, crankshaft, all the gaskets and etc for a 48 cc chainsaw was under $100 delivered. Replacement chainsaw around $1000


Wow! That's good markup potential. No way I could do chainsaws now. My eyesight isn't good enough and wearing glasses where I need them close up but can't see a thing distance with them frustrates me for a start. My fingers aren't as nimble as they used to be and my patience is non existent.
I'd be launching the things 50M down the driveway onto the road.  :embarassed:

Quote
Good Honda lawnmower engines are easy to get probably because the frames are rotten, nobody ever cleans them and they rust from underneath.

The local built ones here with the 2 strokes all had aluminum base plates. Never rusted out but after 20-30 years use which was not uncommon, could get worn through from all the sand and rocks abrading them.  Most people would just drill some holes and rivet a patch over the things as it was usualy the sides that wore through.

I did hot up a couple of 5 Hp IC briggs motors which werw SV engines.  The ones with the aluminium casing but cast iron sleeve that were the higher spec industrial series.  No plastic flywheels or camshafts in those things and a full 1" crankshaft.
Ported the hell out of those, shaved the heads and a few other little things. later on you could get proper performance parts for the things as they were used in the US for Jnr Drag races and other kart racing.  from what I have seen they have largely been overtaken now by the " Predator" type  Chinese engines imported by the likes of Hava fright  and other US stores.  Aftermarket suppliers like Go power sports do every performance mod imaginable  from cams to heads, carbs, valves and casings.  Not hard now to get 20 HP+ out of a 5 hp block and 60Hp_ out of the big twin 20 Hp engines.

Don't know if anyone still makes side valve engines not. think they are a thing of the past well and truly.

Subaru have had a line of Fuel injected engines for some time now as have some other makers and now the chinese are getting onto them as well.  they will all have to go this way I imagine to meet the polloution standards of the US and other places with tight emission regs.
Still probably wont beat the performance of an aftermarket and oversize Tillotson carb on one or a mikuni.