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Author Topic: 4.5kva output  (Read 1302 times)

vegoil

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4.5kva output
« on: October 10, 2018, 10:59:42 PM »
what is the safe kw out put for a 4.5kva 230volt bkb generator on a Lister CS8/1 could I pull 4.2kw without doing damage? the power is being used into storage heaters and a immersion water heater on motors are used.

what would you say the maximim amps for the 4.5kva alternator as not to overload it?
« Last Edit: October 11, 2018, 12:02:02 AM by vegoil »

glort

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Re: 4.5kva output
« Reply #1 on: October 10, 2018, 11:24:54 PM »

Anything under the gen heads rating should be fine.... if the engine will pull it. As long as the engine is smoking ( more than normal for a Diesel) the engine will be ok as long as the cooling system keeps up.

Check the load under load.  Most things are NOT nameplate rating.  Also with heaters ( resistance loads) the actual current can change.
If you put an amp meter on the output ( clamp meter is good) then you can see what you are actually pulling.
More than likley it's not what the rating of the loads add up to.

In my experience a lot of things are over rated in that the power consumption specified is max load when they normally don't pull that much power.
The exception is motors ( did you mean to say No Motors used?)  which have much higher start up currents.  If you are only using heaters you should have no problem but best to switch multiples individually rather than dump them all on at once.

vegoil

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Re: 4.5kva output
« Reply #2 on: October 10, 2018, 11:57:49 PM »
all the power is to go into elements in storage heaters I have one at 3.4kw on its own and a (2.5kw + 1.7kw) together giving 4.2kw also (3kw immersion +0.850kw) heater together, I am planning to have 3 time clocks one for each 3.4kw ,4.2kw, 3.8kw

what would be the maximim amps so as not to over load it?
« Last Edit: October 11, 2018, 12:04:51 AM by vegoil »

BruceM

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Re: 4.5kva output
« Reply #3 on: October 11, 2018, 02:01:12 AM »
For a resistive load, VA is  the same as watts, so 4500/230= 19.5 amps
Just make sure the generator rating is a full load, continuous service and not some BS rating.

vegoil

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Re: 4.5kva output
« Reply #4 on: October 11, 2018, 04:49:16 PM »
thanks for the advice, its an old 1969 Lister CS 8/1 SOM with the original generator I have had the winding's tested and they are all good
I have tried to attach a photo (no go)

Cheers John

glort

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Re: 4.5kva output
« Reply #5 on: October 12, 2018, 01:38:13 AM »

1969 For a CS would be a fairly new Model wouldn't it?  ;D

I would love to see what could be gained from these engines with a turbo. I have seen it done but nothing about power output.
They should be able to produce a LOT more power given  their capacity at the same revs.  Being the things are so over built, I can't see where the wear would be greatly accelerated either.
Wouldn't be hard to do either, main thing would be to run an oil pump for the turblow.

Even if one were running the same sort of loads, I think the stress on the engine might be less when it were burning the fuel easily thinks to plenty of air which allows for lower EGT's and would lessen any bogging of the engine when loads were put on it.

ajaffa1

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Re: 4.5kva output
« Reply #6 on: October 12, 2018, 11:17:13 AM »
+1 Glort, old generators are rated for continuous output unlike the cheap Chinese crap they sell now. If it says 4.5 KVA that`s what you can run off it all day. The higher the load the more fuel you will burn but diesel engines need to be run hard or you get problems with cylinder glazing and carbon build up. Always good to fit a volt meter into the circuit so you can see how it is coping with the load, If you turn on a heavy load the voltage should drop a bit until the engine governor compensates by delivering more fuel. the voltage should then climb back towards nominal. Heavy loads tend to heat up the wiring a bit so there is usually a small voltage drop over about the first ten minutes until things reach a happy equilibrium.

If you are going down the route of timer relays, please use these to trigger proper power relays to distribute the AC current. The cheap Chinese timer relays are supposed to be rated at 20 Amps, I have had two fail in the last 18 months. One of them caught fire and could have burned my house down. I would recommend motor starter relays.

Bob

Bob

vegoil

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Re: 4.5kva output
« Reply #7 on: October 12, 2018, 03:45:31 PM »
I was going to use multiple 30 amp (Chinese) relays. the largest switching load per heater would be 15 amp I thought that I would give it a 50% margin, what do you think?

I have a amp,volt,and Hz meter fitted

Cheers

John

vegoil

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Re: 4.5kva output
« Reply #8 on: October 12, 2018, 05:04:21 PM »
this is the relay on ebay that I Got? 250VAC 30A High Current Contactor Relay Switch 12V DC Board Module Powered Shunt

Is this the same one that gave bother?

 I have a photo but cant seem to get it posted here or any other photos for that mater.

« Last Edit: October 12, 2018, 06:18:27 PM by vegoil »

glort

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Re: 4.5kva output
« Reply #9 on: October 13, 2018, 01:01:45 AM »

I think what Ed is referring to is the inbuilt Relays in the timer themselves.

Might be worth Checking Ed.  I have one and the thing specifies it is rated to 6A only.  I made up a plug in 20A relay so I can connect the timer or The voltage monitoring relays that are also only 6A rated and use them to drive the 20A DPDT relays I got.

The chinese 20A DPDT relays I got a bunch of have been fine. Can't complain at all about them. Even ran one on DC once I discovered to use a DPDT with a Quench load on the off side they have been fine.

Made up a whole bunch of these things on cords now.  PWM dimmer, meters, Night time Switches, and movement sensors.

Before I moved I threw out about 50 leads with the 3 pin computer type connectors on them. I kept about 20 and thought that was over doing it.
With various lights and things I have hooked up, I have now run out.  Not all bad. I only had the Male end not the female which I usualy need so I just go to the hardware and buy a short extention lead. I cut that in half and wire that back to the devise I am hoking up.
The LEADS cost me well less than 50% of what they want for a plug and socket!

Ok for light duty stuff on short runs but the wire is only 1mm so for anything decent I have to get the plug and socket and hook them up with some decent cable.

listeroil

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Re: 4.5kva output
« Reply #10 on: February 02, 2019, 06:26:12 PM »
The 8/1 engined Startomatics with the 4.5kw BKB generator are rated for continuous use at 4.5kw.  However they are rated to BS1958 which states that the generator can be run at 10% overload for a period 1 hour in a 12 hour period. This is also true of the engine. They both conform to BS1958 spec. I do have a Lister brochure which gives this information but at the present moment it is buried under a massive pile, when I find it I will post a picture.

Mick

BruceM

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Re: 4.5kva output
« Reply #11 on: February 02, 2019, 07:22:17 PM »
A true 4.5KW is generous for most homes.  That's like a 6-8KW modern screamer genset.
Lovely machine!

glort

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Re: 4.5kva output
« Reply #12 on: February 02, 2019, 10:40:59 PM »

Just to be pedantic, although it does make a difference in this case, Both 4,5 KVA and 4.5 KW have been quoted for the same machine here.

They are different and running a 4.5 KVA machine at 4.5 KW would constitute an overload.
One would need to clarify what the genny rating was in order to know what the working load that could be used was.

listeroil

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Re: 4.5kva output
« Reply #13 on: February 03, 2019, 09:38:15 PM »
Just to be pedantic, although it does make a difference in this case, Both 4,5 KVA and 4.5 KW have been quoted for the same machine here.

You make a good point so I checked up my Lister manual and brochure for this particular unit and in all the publications it states 4.5KW.  Then I went and checked the brass spec plate on the actual BKB generator and it says 4.5 KVA.  I have now checked a few more Lister manuals and some of them say:-
8/1----4.5 KW----4.5KVA----230V----50CYCLES.     
All very confusing Listers seem to reckon KW and KVA are the same when in fact they are not the same. However IMHO KWs is what Lister advertise in there brochures and manuals and they would not state 4.5KW if it couldn't do that.  So I reckon this generator could easily handle the OPs 4.2KW.


oldgoat

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Re: 4.5kva output
« Reply #14 on: February 04, 2019, 10:31:52 AM »
All you pedants have forgotten to include the powerfactor which is usually stamped on the name plate that decides whether it is 4.5Kw or 4.5Kva