# Generator issue with no load.



## nrp3 (Jan 24, 2009)

Pictures would help.


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## Southeast Power (Jan 18, 2009)

Nclark8832 said:


> I have a customer with a 4 pole 12kva generator self exciting with an avr that suddenly lost power I've checked cables and windings tested avr no problems I can see.
> Manually excite and it produces correct power but will drop to 12v when manual excite disconnected.
> It has a capacitor of some
> Description with two black cables and an earth cable which is connected across the output terminals of the block.
> ...


What type of battery are you using for the manual excite?


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## nrp3 (Jan 24, 2009)

Some generators use caps as the voltage regulator. About all I can see is that with a four pole rotor it spins at 1800 rpm or slightly less maybe if 50hz.


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## Nclark8832 (Aug 11, 2017)

Here's a picture as you can see the capacitor has two black cables crossing the brown and blue output.


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## RePhase277 (Feb 5, 2008)

Get a capacitor with a voltage rating suitable for the excitation voltage and wire it up temporarily and see what happens. A start capacitor for an induction motor would be OK to try.


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## Moonshot180 (Apr 1, 2012)

So with no load, and manual excitation, the generator output is stable?

I would check PT/CT inputs to the AVR, check to be sure the AVR is getting the proper feedback from its sensing circuits that should be connected to the output terminals of the generator.

The AVR relies on these circuits to adjust the excitation potential while under load.

If you have more info..schematic of the generator/AVR that would be helpful.


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## Nclark8832 (Aug 11, 2017)

Yeah 12v battery to pos and neg for exite I get 240 v Ac once off it drops to 12v

It's a sincro bL4 avr not much info available on it, it's in one of the pictures.

Two cables left side are inputs next to them black and red are excite and then two orange sensing wires.

I tested the avr as directed by putting 230 Ac on the input and testing on the excite outputs for the same voltage as per manual and that was correct.

I still don't understand if that capacitor is just a filter or does somthing for excitation.
I tried a new avr but I think that's faulty as same test input 230 put out 640 volts. 

I don't want to order another avr yet just incase its the generstor blowing it or it's just that capacitor. I've ordered somthing simular well identical looking just two digits higher on the pn list only difference I can see is its fitted with a plastic plug and not just rings to fit to a bolt.


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