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Onan 60 kw 3 phase voltage fluctuates

mattyt1984

Senior Member
Joined
Jun 5, 2011
Messages
348
Location
New York
I can't get A steady voltage it constantly bounces around from 200- 300 volts across all legs. I changed voltage regulator but does the same thing.
 

mattyt1984

Senior Member
Joined
Jun 5, 2011
Messages
348
Location
New York
I'm guessing year is around 1980ish attached is pics.
 

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Birken Vogt

Charter Member
Joined
Nov 30, 2003
Messages
5,395
Location
Grass Valley, Ca
I would see what kind of excitation voltage the regulator is delivering. Then feed it the same voltage from a set of batteries and see what it does then. I am thinking loose diode connection or something of that nature, maybe.
 

mattyt1984

Senior Member
Joined
Jun 5, 2011
Messages
348
Location
New York
Could it be the voltage regulator part number onan 305-524? The voltage regulator I changed was the one that actually adjust the voltage higher or lower.
 

mattyt1984

Senior Member
Joined
Jun 5, 2011
Messages
348
Location
New York
I can't find a model or serial. On the outside of panel there is an adjustment knob for voltage adjustment. Also there is a voltage regulator that has part number 305-524 that is inside control panel
 

mattyt1984

Senior Member
Joined
Jun 5, 2011
Messages
348
Location
New York
The hertz is a steady 60 hz. I adjusted the dampening on the cicrcuit board it worked but then went back to bouncing all over. I have video that I could email if needed

Thank you I'm waiting to be registered in smokstak
 

Birken Vogt

Charter Member
Joined
Nov 30, 2003
Messages
5,395
Location
Grass Valley, Ca
While you wait at smokstak, upload the video to youtube, it's easy and then you can just post a link and everyone can see it easily. Emailing videos is much too huge of a file to be passing around.
 

Camshawn

Senior Member
Joined
Jan 25, 2017
Messages
631
Location
Langley BC
Occupation
retired
Are you confirming the voltage readings with a volt meter on the mains? Those meters always bounce but usually settle down after a few seconds. Cam
 

Camshawn

Senior Member
Joined
Jan 25, 2017
Messages
631
Location
Langley BC
Occupation
retired
You said you changed the AVR. Did you change the voltage adjustment pot on the door? Also, what shutdown are you getting? I have seen pots go bad causing erratic readings due to vibration on generators and other equipment. If yes, have you gone through all the connections looking for a loose or partially broken wire including the field connections and the sensing wires?
 

mattyt1984

Senior Member
Joined
Jun 5, 2011
Messages
348
Location
New York
I've adjusted the pot with a screwdriver and the damper. It woreked for. A day they it's bouncing around again.
 

Camshawn

Senior Member
Joined
Jan 25, 2017
Messages
631
Location
Langley BC
Occupation
retired
The AVR is the circuit board in your video with the little pots. I have replaced several AVR’s because the little pots develop dead spots in them.
I would look for a schematic to help identify test points for the cause of the shut down. It has been a while since I looked at one of these generators and my memory is a little fuzzy. Cam
 

mattyt1984

Senior Member
Joined
Jun 5, 2011
Messages
348
Location
New York
I finally got a new board and that was the issue. Next question how do you rewire for 480 see attached pic of plate
 

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MarshallPowerGen

Senior Member
Joined
Nov 26, 2017
Messages
483
Location
Northwestern USA
Occupation
Generator Technician & Equipment Mechanic
240/480 or 277/480? Diagram is there, you just need to connect your leads as shown. Pull the lid and see how they're currently set up and compare to the diagram, then change to the output you want.
 
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