Generator with no load and de-energizing

R

Thread Starter

Raman

Hi,

I want to know what happens to the torque supplied by the engine when the brushless generator is suddenly offloaded while the fuel supply doesnt change necessarily? What does the term de-energizing implies?
 
Raman,

I think one reason you haven't received any response(s) to your query is that we don't quite understand the post. The title, the synopsis and the body are all a little different--enough to cause some confusion (at least on my part).

You haven't really told us enough about the operating conditions at the time of the "event." In other words, is the engine-generator running independent of other generators ("islanded") supplying an electrical load? Or is it synchronized to a grid with other generators?

Also, I'm a little confused by some of your terms, also. A synchronous generator (usually used for production of AC (Alternating Current) requires a controlled source of power for producing the electromagnetic field on the generator rotor necessary for establishing generator terminal voltage and for synchronous operation. The engine governor usually controls engine-generator speed in one of two modes: Isochronous- or Droop Speed Control. Isochronous is usually used when the generator is being operated independently of other generators and a grid; Droop Speed Control should be used whenever a generator is synchronized with other generators on a grid supplying a large electrical load.

If the generator rotor suddenly loses the source of power for the electromagnetic field but the generator is NOT disconnected from the load (motors; lights; etc.) and the fuel to the engine is not reduced there is a good chance that the generator can lose synchronism and be damaged by internal heat which will result in the generator when the "field" is lost.

If the generator is suddenly disconnected from the load but the fuel to the engine is not reduced it's extremely likely the engine and generator will overspeed which can lead to catastrophic results--and possible human injury or death. Uncontrolled overspeed is NOT a good thing for engines (or turbines) or generators--not at all.

"De-energized" could mean many things in different contexts. It could refer to the removal of power from the generator field.

But, again, we don't have very much information regarding the circumstances of the event(s), so the more information you could provide the more information we can provide.
 
Raman... which type of generator is it... brusless meaning with a static exciter mounted on shaft, or brushless meaning permanent-magnet rotor?

Regards,
Phil
 
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