Generac Model 0058830, 10KW Volts, RPM & Hertz fluctuating

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Kirk1024
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Wed Oct 09, 2019 6:31 pm

The generator voltage, RPM, & Hertz are fluctuating causing the lights to flicker. This is happening under all loading conditions and seem to be getting worse. Unit is on LP gas.
Chris
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Wed Oct 09, 2019 6:34 pm

Do you know what the fuel pressure is to the unit, and how close is the LP regulator to the unit's fuel inlet?
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Kirk1024
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Sat Oct 12, 2019 5:37 pm

Tested LP pressure at unit measured 10"WC when running. Increased it to 11"WC when running. Noticed that the WC gauge fluctuates a lot maybe 59-60 PPS.
I did change the air filter and replaced the spark plugs. Plugs show no deterioration, they both have a ivory coating on ground element otherwise look very clean.
Under no load conditions: (Circuit Breaker Off)
RPM = 3572 – 3624, Hz = 59.4 – 60.5, Volts =235 – 266 VAC
Is it possible that the valves are not closing all the way? Manual states that the valves need to be adjusted after 300 hrs. I have not done this.
Kirk1024
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Sat Oct 12, 2019 5:45 pm

Oh Forgot... LP line from regulator to unit 24" long, with 2- 90's and 1-Tee 1/2" pipe with 1/2" hose.
Birken Vogt
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Sat Oct 12, 2019 9:05 pm

It is unlikely from my experience that valve adjustment would cause fluctuating RPM, but adjusting the valves and checking gas pressure absolutely must be known good before continuing with engine performance diagnosis. Besides the fact that it should have already been done once and getting close to due again.
Kirk1024
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Sat Oct 12, 2019 9:32 pm

Thanks for the info. I will adjust the valves and also check the compression on the cylinders.
Chris
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Sat Oct 12, 2019 10:12 pm

I almost wonder if the issue is really a bad AVR in the controller and the slight engine RPM fluctuation has just always been there. The slight movement in RPM based on your readings is fairly normal (only about 1Hz), however the voltage jumping around doesn't correspond with that small frequency movement. The normal would be 2V per Hz. This sounds more like dirty slip rings or an AVR in the controller that's dying. Could also possibly be a loose sensing wire going back to the controller. Those would be the 11&22 wires.
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Kirk1024
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Sun Oct 13, 2019 7:34 pm

I agree that the RPM & frequency is not bad for a 2 pole, 3600 RPM generator.. Nice to know info of 1 Hz = 2 volts. Checked the wiring 11 & 22 to the controller board and can see no problems. Board is P/N 086680B C1112 , REV F. I see where the brush leads go into the generator but I can not see how to get the the brush holders to check the condition. Go in through the fan vent or other?
Don
Kirk1024
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Sun Oct 13, 2019 7:58 pm

Oops.. Board is 0H6680B
Don
Chris
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Sun Oct 13, 2019 10:35 pm

You can test the resistance at the harness. That is an old style controller that has been replaced by a very expensive kit and the 0H6680D controller.

The 0 and 4 wires will be in the smaller Ampseal near the rear of the controller. You will need needle probes or something similar to test with. DO NOT jam the meter leads into the small sockets!

The 2V per Hz number is for each winding (line to neutral), so it would be 4V line to line.

The 0H6680DSRV controller kit can be found here: https://shop.gentekpower.com/products/g ... cement-kit
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
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