Generator High Voltage

[Kirk W]

I agree with both of the 2 preceding posts. It is possible that the problem was caused by moisture or even dirt, but the odds of it staying resolved are not great. 

[oldjohnt]

2 hours ago, Tcwndsr said:

This shows the value and importance of just getting in there and wiggling wires, cleaning connections, doing some simple troubleshooting before starting to throw expensive parts at the problem.

A big AMEN to that. I like to keep it simple, do some basic troubleshooting, check, remove and clean and re attach connections, and if you're lucky (unfortunately may NOT be the case lol)  you may cure the problem. If you have an EMS that should reduce the risk if you get any more high voltages but don't count your chickens yet, your high voltage condition may rear its ugly head again. If so, a prime suspect remains that "Voltage Regulator" and perhaps its adjusting pot has become dirty, corroded or took on excess moisture ??  

 Anyhow congratulations for now at least and keep a close eye on things.

Thanks for the feedback

John T

[Tcwndsr]

Oh yeah, I’m sure it’ll be fine until I really need it while boondocking out in the middle of nowhere in New Mexico. Don’t you just love intermittent problems?

[QuestVent]

I know this is an old thread, but I've got a similar issue with my Generac NP-66G. Mine has been giving me issues for the past week or so, and now is to the point where it reliably stops generating power within 15 minutes of start. When that happens, the engine bogs down as if under heavy load, the output reading goes up to 160V at 59hertz, and a GFI outlet in the vanity trips just before the EMS kicks in and disconnects the generator. We've occasionally had the problem with the GFI outlet for the past year or two, I just never put 2 and 2 together to see it as having anything to do with the genset.

This is more or less consistent at this point. So, I'm just confirming that I'm also having the same issue with the voltage putput going up to 160V before CB3 apparently opens. Sometimes power will come back for another minute or two before it does the same thing. The engine has always ran perfectly, whether under load or not.

[Kirk W]

With a little luck, Tcwndsr will see this and return to let us know if his problem sayed away. I really can't  see any  reason why  a  generator problem would cause your GFI to trip, but I suppose it is possible. 

[oldjohnt]

QuestVent, regarding your GFCI. A GFCI ONLY deals (senses and measures any difference between Hot and Neutral) with current flow that passes through its Torroid Coil and DOES NOT control what's happening upstream and before it.

That being said, if there is a load attached with current passing through it and input voltage rises that will affect its load current (Yet its still only the DIFFERENCE in Hot and Neutral current that matters). While the GFCI may or may not have a problem, I don't see it as affecting your genset operation but NEVER SAY NEVER

Its possible a fault or short etc that's fed via the GFCI (either direct or downstream via the LOAD terminals) might draw excess current and somehow cause the genny to shut down (or EMS trip) for over current and/or the GFCI to trip, BUT THATS THE FAILT OF THE DEFECTIVE OR SHORTED LOAD,,,,,,,, NOT THE GFCI WHICH IS MERELY DOING ITS JOB CORRECTLY...

Any weak or loose or carboned or resistive connections or excess dirt or moisture can affect your gennys, especially electronics and circuit boards etc, operation.   

John T

 

Edited March 19, 2020 by oldjohnt

[Tcwndsr]

My generator  has run well since I had this issue last Spring. Unfortunately I can’t point you toward what may have caused the issue, cleaning and tightening connections somehow worked for me, my next step would have been a new voltage regulator.