Generator starts and runs fine. Turn on roof a/c, fan blows but compressor doesn't come on. Voltage at all ac outlets bounces around from 25volts to 118volts. Transfer switch working fine. AC outlets work fine when plugged into shore power as does the air conditioner. Circuit breaker inside coach is fine. Circuit breaker on generator's alternator section is not tripped. My guess? The alternator's capacitor/voltage regulator is shot. Could be the whole control board I guess. Or stator ,rotor. What do the rest of you think?

Jim (aka Hum)

Brushes may be shot. What type of gen? I have a contact that works on them that might be of help. Tom bought his euro off him. He spent many hours on Tom's gen getting it running for his trip back to Texas. Will see if I can come up with his phone#.

It's an Onan Emerald I BGEF 4000

Jim

Is the engine RPM steady at 3600 RPM when you are getting those varying AC voltage readings?

Onan uses a four pole alternator so engine runs 1800 RPM.

quote:

Originally posted by L78steve:
Is the engine RPM steady at 3600 RPM when you are getting those varying AC voltage readings?

As far as I know, it's running at 1800 RPMs but it doesn't have a tach on the generator.

2 pole or 4 pole the engine needs to be in tune and running steady. Otherwise frequency and voltage will be all over the place. Only other devise that can cause fluctuations is the voltage regulator.