350 kva generator

J

Thread Starter

jacob25

Good day,
My 350 kva generator is shutting down at every 30 seconds and indicating on the dashboard, "under voltage." It's a Perkins generator of 2200 series.

Please Assist.

jacob
[email protected].
 
Jacob,

What does the generator instruction manual say is causing the alarm?

I'm totally guessing here, but what is the generator terminal voltage when the unit reaches rated speed? If it's very low, then that could be the cause of the under voltage alarm condition--which would mean that something is wrong with the generator exciter ("AVR"). And, the engine control could be set up to shut the unit down to conserve fuel if there is no generator terminal voltage because the unit can't be loaded if there's no generator terminal voltage so no sense wasting fuel if there's no generator terminal voltage.

But, the first question to ask when something like this occurs to a unit which has been running fine and suddenly develops this kind of problem: What has changed between the time the unit was working fine and now when there is this problem? Was there a lightning strike which tripped the unit? Was there some kind of overcurrent or overload or overvoltage condition which tripped the unit?

Have you checked to make sure the generator excitation system ("AVR") is working properly (it should be making some voltage to apply to the generator rotor windings to develop generator terminal voltage when the unit is at rated speed. Generator terminal voltage is a function of both speed and excitation--so if the unit reaches rated speed but doesn't develop generator terminal voltage then something is probably amiss with the exciter.

Some smaller generators use rotating diodes on the generator shaft to convert AC into DC to apply to the generator rotor windings. Sometimes if there was lightning strike or some other kind of electrical fault these diodes can fail.

Sometimes it as simple as replacing a fuse somewhere in the exciter control system. But, again, we're back to the unit instruction manual--which should always be consulted for troubleshooting help.

Please write back to provide more information, and to let us know how you resolve the problem.
 
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