Generator output voltage too high

Generac, Guardian, Honeywell, Siemens, Centurion, Watchdog, Bryant, & Carrier Air Cooled Home Standby generator troubleshooting and repair questions
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Stevew
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Sat Mar 30, 2019 8:02 pm

Hi guys, hoping you can help explain what might be wrong with my Generac generator. It's a model 0055060 20kW. We noticed during the last outage that the output voltage was WAY too high on the unit and the lights were very bright. We shut the unit down to prevent any damage to the house. What would cause something like this? The engine seems to be running normally and not any faster than usual. There were not any alarms on the screen just the normal date and time.
Chris
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Sat Mar 30, 2019 8:14 pm

This is almost always a bad voltage regulator (AVR). On that model generator, we call them pre-nexus, the controller didn't monitor output voltage, just basic things like engine speed, oil pressure, engine temp, etc. The voltage regulator was a separate device and system all together. The voltage regulators sometimes fail wide open and you will see around 320VAC output. The replacement voltage regulator you need you can find here: https://shop.gentekpower.com/products/g ... ulator-avr

It just gets swapped wire for wire and then once installed, run the generator with the breaker off and adjust the small brass screw until you see around 240-245VAC output on the generator side of the breaker.
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pancho_fhg
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Sun May 05, 2019 12:28 pm

Hi, i have the same problem but it is a brand new G0070432 - 22 Kva generator, i need to adjust the voltage in regulator or it may be other issue?
Thanks for the help...
Chris
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Sun May 05, 2019 12:31 pm

pancho_fhg wrote:
Sun May 05, 2019 12:28 pm
Hi, i have the same problem but it is a brand new G0070432 - 22 Kva generator, i need to adjust the voltage in regulator or it may be other issue?
Thanks for the help...
What is the actual output of the unit and what is the voltage you are trying to achieve?
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
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pancho_fhg
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Sun May 05, 2019 12:35 pm

Chris wrote:
Sun May 05, 2019 12:31 pm
pancho_fhg wrote:
Sun May 05, 2019 12:28 pm
Hi, i have the same problem but it is a brand new G0070432 - 22 Kva generator, i need to adjust the voltage in regulator or it may be other issue?
Thanks for the help...
What is the actual output of the unit and what is the voltage you are trying to achieve?
The output is around 300v, 149 and 152 each line, it sould be 240, 120 each line.

Thanks for the help...
Chris
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Sun May 05, 2019 7:54 pm

This sounds to me like you have a loose connection at one of the sensing wires. There is a large white 4 wire connector under the controller that comes directly from the stator that you should check to see if a pin was pulled out. 11 and 22 are the 2 sensing wire numbers.
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pancho_fhg
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Mon May 06, 2019 8:30 pm

Chris wrote:
Sun May 05, 2019 7:54 pm
This sounds to me like you have a loose connection at one of the sensing wires. There is a large white 4 wire connector under the controller that comes directly from the stator that you should check to see if a pin was pulled out. 11 and 22 are the 2 sensing wire numbers.
Thanks a lot, i checked the connector, it seemed to be ok, but i unplug and plug again and it started to work OK.

Thanks you for the support.
Chris
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Mon May 06, 2019 9:04 pm

Keep an eye on it! Voltage like that could do a lot of damage...
Generac tech for over 12 years. I'm here to help!
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