MEP831A - Overvoltage Fault

[CommieGIR]

Hey All,

Recently picked up a MEP831A, engine purrs well and shows voltage on the meter, however has a persistent overvoltage fault and turning on battle short doesn't provide any output at the onboard outlet.

I've ordered Klopps Governor controller since the built in one appears to be toast, doesn't adjust motor speed at all or cause the motor speed to go unstable as part of the adjustment procedure., but wanted to see if there was any other troubleshooting I could do.

I noticed when I shut it off I have to manually close the governor to shut it down, assuming this is another good sign the governor controller is toast.

 

[Ray70]

Kurt is our resident expert on the 831, he'll get you straightened out.
Start with his controller and see if that solves everything.
Make sure you adjust the linkage rods 100% by the book otherwise it will never run right, no matter what you do with the controller.

 

[kloppk]

Kurt here...

No power at the outlet may be due to the tiny circuit breaker on the GFCI is tripped. Also the GFCI contacts can be flakey. Sometimes I have to tap the Reset button mine to get juice to the outlet.
If the meter shows AC voltage the outlet should get power assuming breaker and GFCI are happy.
Not properly shutting down could be a bad GC or its way out of mechanical adjustment.
Have you tried doing the governor adjustment procedure in the -13&P TM?
Results?
With the set running what's the AC voltage across GC terminals A & B?
Results?

 

[CommieGIR]

Hey Kurt!

So I attempted a calibration of the Governor as found on 0020-1, and none of the adjustments result in any change, like I cannot get the engine to go unstable using the POT adjustments.

Terminals A-B = 147v
Interestingly, there's no voltage on F-G which should have 24v. Might explain the Governor Controller not doing anything.

 

[kloppk]

The problem is the Overvoltage fault the Fault monitor is reporting is causing the K12 Fault Relay to turn on which kills power to the GC. No power at F-G.
K12 Is the leftmost relay behind the gauges. If S1 is in Run and the led inside K12 is on while its running it indicates the fault monitor is trying to shut the engine down by removing power to the GC.

Try this. I assume you have good batteries in it.
Move S1 from Stop to Run. Do not start it. Which Fault Monitor lights are on?

Is the over voltage light on?
If overvoltage lamp is on then put S1 in Stop. Disconnect the white connector P17 from the upper side of the inverter. Move S1 from Stop to Run. Do not start. Is the overvoltage light on? If so then the Fault Monitor itself may be bad.
I've had to repair a few of then due to false faults.

 

[kloppk]

The 147 volts indicates the GC has no power or isn't working. Should be 178 ish volts if idling properly with no load.

 

[CommieGIR]

Try this. I assume you have good batteries in it.
Move S1 from Stop to Run. Do not start it. Which Fault Monitor lights are on?

With the switch on and engine off, only the 'No Oil Pressure' fault light is on.

 

[kloppk]

With the switch on and engine off, only the 'No Oil Pressure' fault light is on.

OK that's normal.

 

[kloppk]

Sounds like the inverter is reporting an OV fault to the Fault Monitor which in turn is causing K12 to turn on. Killing power to the GC.
The inverters in the 831's are trouble prone. Most people have problems with OL or SC faults.

 

[CommieGIR]

Is there another option for the inverter or are they just not worth fixing?

 

[kloppk]

No schematics or trouble shooting info for the inverter. It's a pluck and chuck item.

High humidity can cause issues with them. Have you had high humidity lately while you've been working with it?

The rest of the generator is pretty solid.

I have a supposidly good used inverter on it's way to me. If it tests good that may be an option.

Also the PMA and Inverter can be yanked out and replaced with a conventional gen head. I've done that to several 831's. I have produced gen head swap kits with a new GC, wiring harnesses, hardware and instructions on how to do it.

 

[CommieGIR]

I'd be interested. Its in Georgia so yeah, high humidity is a possibility.

What's the possible gen heads you can swap on? About the same output rating or better?

 

[kloppk]

That would be high humidity. Some people have had luck removing the main board from the inverter, drying it in an oven and then sealing the potentiometers to keep the moisture out.

Heads to swap in need a J609B configuration. Most buy the gen head from Mecc Alte. It's a 4.2 kva head. Ive used them several times. Last one I bought was $350 including UPS shipping.

 

[CommieGIR]

Extremely reasonable, and that's internally regulated versus needing an external regulator?
EDIT: Yeah took a look, they have an internal regulator. Is it the NPE32 people are using?


I'm going to take apart the inverter today and look for issues and clean it out.

 

[kloppk]

The Mecc Alte head is internally regulated via a capacitor.

 

[CommieGIR]

Fairly certain the converter/regulator is toast. There is a pot adjustment internally for setting overvoltage trigger, and I did get it to output current to the outlet, but without the Governor controller to handle when a load is applied, it can't power anything.

 

[kloppk]

Gotta get the GC changed so the engine speeds up to support the load.

 

[CommieGIR]

GC is changed out, I can see it has voltage during cranking but after the engine catches the K12 relay is locking out voltage to the GC

 

[kloppk]

That's due to the OV fault signal from the inverter. You can unplug the cable from the back of the fault monitor.
This will prevent it from responding to the OV fault or any other fault and keep power to the GC.

 

[CommieGIR]

I will give that a shot in the AM.