Very low voltage

Portable standby generator troubleshooting and repair questions. (Gasoline, diesel, propane, natural gas)
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Joined: Sun Mar 03, 2019 6:34 pm

Sun Mar 03, 2019 6:59 pm

What I have is about 12 year old GP17500e portable standby generator, has always been under cover (never out in the elements). It fires up and runs fine although there is only 25 volts output at the top of the 50 amp breaker. The red light on the voltage reg is lit, I’ve checked the brushes and they appear in good shape (still springy and long). Any help would be greatly appreciated
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Location: Clawson, MI

Sun Mar 03, 2019 7:09 pm

It sounds like maybe the voltage regulator is bad if the voltage is so low, yet the LED is lit. Does the light appear fairly dim? I'm assuming yes from the low DPE voltage I'd guess it has.

Probably the easiest test is to manually flash the 4 wire with 12V from the battery and see what the output is. If it's much higher (won't be normal still) you can almost count on a bad AVR. You should also test the voltage coming back to the AVR on the DPE circuit (wires 2 and 6 at the bottom of the AVR). It's power to the AVR and if that's abnormally low, you could have a bad DPE winding, or possibly a DPE breaker with high resistance.

If the LED wasn't lit, I'd suggest some other tests, but let's start there...

If you need any parts along the way just let me know! The store is almost up and ready to go, but still doing some tweaking on the back side.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
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