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strange voltage behaviour

strange voltage behaviour

hi all, i hope somebody can help me. I recently purchased a 20KVA single phase generator for use with mobile sound equipment.

when we put any load on it it runs fine for a few minutes, then the voltage drops to zero. there is an onboard volt meter, and the needle justs drops to zero, any equipment plugged in just dies.

has anybody got any idea what the problem might be. id be grateful for any info.


RE: strange voltage behaviour


Is the voltage drop once only or repeatedly?
Does the speed of the engine drops?
Any trips?
Have you checked the phase connections?
What is the load capacity?
Give some more details.
Check your excitation voltage regulator card.
Offline flash a battery across terminals (usually) x-xx in the excitation card.
Connect a recorder to observe the voltage pattern.

RE: strange voltage behaviour

Does it slowly drop to zero, or all of a sudden?

"Venditori de oleum-vipera non vigere excordis populi"

RE: strange voltage behaviour

the voltage stayed normal for 5 minutes or so then dropped quickly to 0 for maybe 1 minute, then back up again.

ive just spoken to my friend. and he says that its not supplying any voltage at all now when we use it.

the engine (yamahe diesel) doesnt change note when the voltage changes.

i think the capacity is 20kw (says that on the side of the unit).

im not hugely experienced in this area, so if there is any more info i can give, ask away.

RE: strange voltage behaviour

Does this voltage drop occur only when the generator is loaded?
I will suggest you run the generator without any load connected, and observe if the voltage drops.

RE: strange voltage behaviour

Check for a thermol overload switch tripping and resetting

RE: strange voltage behaviour

It sounds to me as though something is detecting a fault condition and dropping the load. Best to get someone in to have a look at it.

It is not really possible to come up with a useful suggestion without a lot more information.

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