MEP804A under then over voltage

[319cssb]

When I start the generator i most of the times get an under voltage light . When resetting, it shows over voltage and shuts down. The Gauge shows 174v on all three phases at 60 hz.
Sometimes the generator gors straight to the over voltage light and shuts down. The voltage adjust has no impact and the rheostat is new and does the same as the old one did. Does anyone know what could be going on?

 

[robertsears1]

Did this happen all of a sudden after normal running for a while or did you just get this 804 and have never seen it run normal? A little more information would be helpful. Do you hold the switch in start until the oil pressure stabilizes?

Robert

 

[319cssb]

Yes , I am starting the generator as per -10.
Never seen it run without issue. It was used paralell before and was reset in 2011 and has 500 hours since.
I replaced the mosfed im the voltage regulator and it looks pretty normal.
What does this little square potentiometer in the right lower corner of the voltage regulator do?

 

[robertsears1]

Please give this a try. From your list of equipment, it doesn’t look like you have a genset so you may not have experience cranking one. These MEP generators start different than any other electric start engine I have ever been around. You need to hold the start switch in start for at least 10 SLOW seconds after it is running. It seems strange but that is how you energize the field to make electricty. I have gotten a under voltage light when I was too fast releasing the switch. Also, make sure the toggle switch in the lower middle of the panel is in UNIT, not parallel. Battle Short should be off, red guard down.

Robert

 

[319cssb]

Hooah, I had a mep804 , several mep803 and mep831 before, but ill crank for an extra few seconds next time.