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rjfmail's avatar
rjfmail
Explorer
Jul 06, 2015

Generator running - no power - status light on

Onan Marquis Gold 5500 Watts Cummings Model 5.5 HGJAB GAS

Genset runs for approx 20 minutes then power to motorhome shuts off while genset keeps running. When turn off Genset for 15 min and resart power is resumed but then shuts off again in approx 20 min while genset keeps running.

Checked circuit breakers - still on. No load except few ceiling lights. Any suggestions

8 Replies

  • FIXED! - Transfer switch failed after it heated up. Replaced and ran Genset for 3 + hours confirming solution. Both under a/c load and without any load.

    Thanks Guys for your wisdom/experience
  • Thanks to every one that responded. I am investigating/pursing the transfer switch as problem. Also was told voltage regulator could be overheating after the 20 min window and shutting down etc.

    Will follow-up when have resolution.
  • Transfer switch in normal position is to shore power.

    The transfer switch relay pulls the contacts to the generator position sounds like the transfer switch is not holding and defaulting back to the shore power position.
  • kjfmail,

    The lights are probably 12V and have little to do with the APU (genset). Your APU has an electronic (digital) controller that controls both the engine and the generator output (iirc). I suspect that that part is failing. A replacement can be had, but I would suggest that you first purchase the service manual (if you can't find someplace to download it - I didn't even look for one) and then get someone that is electronic stuff savvy to look at it. If you have to buy a replacement from Cummins/Onan, remember to bring your duck tap to secure your wrist to your ankles. They are very proud of the parts that they supply.

    Good Luck

    Matt
  • He said the Genset keeps running while the power cuts off. Doesn't sound like oil level to me.

    rjfmail, your generator is hooked to a switch (and I can't remember what's called, but somebody on here will tell us.) What that switch does is switches the source of your AC power between shore power and generator power as you can't be getting AC power for your motorhome from both. Normally if you have shore power plugged in and you start your generator the switch will turn over to get power from the generator. When you turn the generator off it will switch back to shore power. When you only have AC power coming in from one source, whether that is shore power or generator power, that switch will change to that source. Sounds to me like there is a good chance that switch is malfunctioning.
  • Check the oil level. Next time it is running also try putting it under a load with an AC running and see if that makes a difference.