Lister Engine Forum
How to / DIY => Generators => Topic started by: guest23837 on September 20, 2018, 09:30:10 PM
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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!
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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
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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.
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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?
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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
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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
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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
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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
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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
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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
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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
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https://www.ebay.com/itm/Yanmar-6KW-Diesel-Generator/183384598167?hash=item2ab292e697:g:pBIAAOSw-mdbdzYO
I am probably worrying about nothing
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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
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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
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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
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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
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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....
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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.
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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
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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.
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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
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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
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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
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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
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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.
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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.
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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?
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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
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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
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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
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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
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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
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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
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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.
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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
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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
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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?
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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.
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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....
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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.
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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
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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!
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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
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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....
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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!
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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
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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?
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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
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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
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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!!)
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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???
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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?
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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??
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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
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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
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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
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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
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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....
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The AVR is in a small plastic tub. The bulb doesnt light connected neutral to earth
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Is the output steady and not varying?
What is the N-E voltage now?
Ed
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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
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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
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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
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Confirm - The AVR is still in the plastic tub and not touching ground anywhere with the above readings?
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Yes its totally isolated Ed
P
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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
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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
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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!
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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
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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 ?
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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
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The cheapest capacitor meter will work just fine.
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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
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I'm not familiar with capacitor regulated alternator designs, but hopefully someone else is and can help you.
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> 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.
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> 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
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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.
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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.
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thats 50 HZ mate
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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!
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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
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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
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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
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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
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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.
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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.
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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
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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