Forum Discussion

LaPalmaMama's avatar
LaPalmaMama
Explorer
May 13, 2013

Genset issue

Gen is shutting itself down. It worked fine for a trip and then upon returning home it shuts down after running a couple minutes it shuts down and blinks a code 12 that reads:

"Inverter overvoltage fault
(controller not able to regulate to rated voltage)

Corrective Action: Check weather the vehicle engine and genset share teh same starting battery. If so, and this fault action occurs when cranking the vehicle engine, low battery voltage may be causing this shutdown. Increase teh battery capacity or install a separate battery and battery charging system for the genset."

Can this be explained in lamans terms for this mom? Do I need to take it in or is there a simple fix? I don't know why anything would be overloaded when nothing is plugged in or running.
Thanks
Class A

7 Replies

  • Grillmeister's avatar
    Grillmeister
    Explorer
    May 13, 2013
    Jim, thanks for the response. Very interesting.

    Good luck to the OP, be sure to let us know the outcome.
  • LaPalmaMama's avatar
    LaPalmaMama
    Explorer
    May 13, 2013
    It's gas.
    The fault code is not for cranking but for shutting down.

    My first blink was 3 which says "Three Blinks indicates shutdown due to some other abnormal condition." then I get the 12 code. blink pause blink blink

    What model. When it was serviced last year the place left a note that says I have the incorrect book. Ihave a Onan book but apparently for a different modle? The model they tell me I have is a 5.5 HGJAB
    It is possible the code I am reading is for a different gen model.
  • Jim's avatar
    Jim
    Explorer
    May 13, 2013
    Grillmeister wrote:
    Just to bump this up again, I have a question. Is it possible since the generator is being exercised with no load, is it going over the voltage specs.


    I don't think so. From my experience, if a generator is over-volting, it's either dirty slip rings or the Voltage Regulator (VR). AND, it's possible dirty connections could cause the VR to think the slip rings are dirty.

    Mine runs about 132 volts until I place a load on it. So I guess I am suggesting the OP start the genny and turn on some small loads like fans, lights and maybe the fridge on AC.


    Classic symptom of a bad regulator but...check the slip ring resistance and clean all the connectors with good contact spray. IMO.

    I know you are supposed to let the genny warm up before placing loads on it, but most start up with at least the converter being on. It might be a simple experiment.


    Warm up isn't really necessary for most generators. The engine spins up to speed, the control system has a delay in it to prevent applying the voltage to any load after it measures the AC voltage, 108-130V, and the Hz, 58Hz-62Hz, if outside these ranges, it's suppose to shut down. If it's outside these ranges and doesn't shut down, it's almost always the VR.
  • MrWizard's avatar
    MrWizard
    Moderator
    May 13, 2013
    what model generator
    sounds like you might have the Genirac inverter model
    and the 120v AC output voltage is too high

    the fault definition for cranking the engine , means low voltage to the running genset when trying to start the drive engine
    this should not exist at this point with genset being the only thing running
    could be a bad battery
    where is the genset connected? engine battery or house/rv batteries

    if the converter/charger only charges the house from shore or genset and the genset is connected to a low/bad engine/chassis battery, this might cause your problem

    but the inverter too high does not seem too match engine crank battery low
  • Grillmeister's avatar
    Grillmeister
    Explorer
    May 13, 2013
    Just to bump this up again, I have a question. Is it possible since the generator is being excercised with no load, is it going over the voltage specs.

    Mine runs about 132 volts until I place a load on it. So I guess I am suggesting the OP start the genny and turn on some small loads like fans, lights and maybe the fridge on AC.

    I know you are sopposed to let the genny warm up before placing loads on it, but most start up with at least the converter being on. It might be a simple experiment.
  • Jim's avatar
    Jim
    Explorer
    May 13, 2013
    The fault code description applies when cranking the generator. It's incomplete as it doesn't mention what the code means after it's been running for a while.

    What I think it MAY be is dirty slip rings. Take a 1/2" X 12" long square stick and glue some sand paper on one end. Locate the air slots on the end of the generator and with a flashlight, locate the two slip rings. Start the engine and rest the sandpaper on each slip ring in turn as the engine spins. This cleans the slip rings and brings the resistance back down to normal range.

    If it still stalls after running two minutes, then it's probably the voltage regulator.

    Other causes for this symptom (but a different code than you're getting) is low oil level. Check that anyway...just to be sure.
  • deandec's avatar
    deandec
    Explorer
    May 13, 2013
    It sounds like the voltage regulator is malfunctioning?

    Is this a gas or diesel genset?

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