I have a MEP-831a that I bought with 41 hours on it. It currently has 49 hours. We were using the generator and it was working fine with no issues. The next day we went to restart the unit and now we have a problem. The unit restarts and comes up to speed normally. The voltage gauge will rise to a normal level and then a second or so later it will drop all load and the overload light comes on. Nothing is plugged into the unit so if there is a short it must be internal. I'm not able to determine if it's a low voltage or high voltage short. Nothing appears amiss inside and all connections are tight with the silicone sealant. When the overload light comes on it seems as if the automatic governor is losing power because there is no response when the red button is pushed. If I try to manually over ride the automatic governor the unit will shut it's self down. Any help would be appreciated!
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MEP-831a Overload
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Dewie38
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The problem is with the inverter.
The inverter has a short circuit relay inside that is tripping, the overload/short circuit light will come on but it is not an overload fault it is a short circuit fault because the set is shutting down.
On an overload fault the circuit interrupter will just trip on a short circuit fault the set will shut down.
Sounds to me like you have a bad inverter. It will probably cost more to replace it than you paid for the gen set.
The inverter has a short circuit relay inside that is tripping, the overload/short circuit light will come on but it is not an overload fault it is a short circuit fault because the set is shutting down.
On an overload fault the circuit interrupter will just trip on a short circuit fault the set will shut down.
Sounds to me like you have a bad inverter. It will probably cost more to replace it than you paid for the gen set.
Dewie38
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So that would be an overload fault not short circuit.
Still a function of the inverter though.
Start the set and as soon as it comes up to speed and voltage put on the battle short switch, that should bypass all faults except short circuit.
The overload/short circuit light should still come on but the circuit interrupter should stay closed.
Still a function of the inverter though.
Start the set and as soon as it comes up to speed and voltage put on the battle short switch, that should bypass all faults except short circuit.
The overload/short circuit light should still come on but the circuit interrupter should stay closed.
Got home last night and it wouldn't act up. Everything was normal. I got talking with somebody and he reported as having seen the same problem. He actually has seen it several times and attributed the issue to moisture in the inverter. He found that by unplugging the 6 prong plug at the (right side, bottom front corner) he could get the unit to start and run so the inverter would dry out. He warned that with this plug pulled the fans won't run, so don't close the cover. This makes total sense because the night after we shut down there was a significant rain storm and there was a small amount of water inside the enclosure. I'm thinking maybe I'll find a surplus tarp and have a boat place make me a cover for the unit so I don't get any corrosion in the inverter.
Dewie38
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Yes, cover it up, if at all possible, store it in a shed or garage.
Had the same problem with one of mine that I took out of my garage and left outside covered up. So I don't leave them outside anymore.
The fans don't run because there is no AC out of the inverter because he pulled one of the inputs to the inverter from the PMA.
All you would really have to do is open the little door on the top of the inverter where the voltage selector switch is and run the set that way.
Had the same problem with one of mine that I took out of my garage and left outside covered up. So I don't leave them outside anymore.
The fans don't run because there is no AC out of the inverter because he pulled one of the inputs to the inverter from the PMA.
All you would really have to do is open the little door on the top of the inverter where the voltage selector switch is and run the set that way.
Hauled the generator back up north this weekend. Went to fire it up and got the overload light came on right away. It wasn't raining out, but it was a cool damp foggy morning. Suspecting moisture was the culprit, I opened the inverter cover and then fired up the generator. It was cool out so I closed the cover and let it run like this for a good 30 minutes. The nice thing is that the inverter cover open the hour meter doesn't work so you aren't accruing hours unnecessarily. At the end of the 30 minutes, I shut the set down and closed the inverter cover. Fired the unit back up and it picked up the load right away. Definitely a moisture related issue.
g2reeves
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Not sure if anyone's still watching this thread, but I've had a similar issue with a unit I picked up a couple weeks ago at OKC. Meter claims 310 hours, and the engine is in great shape. Runs like a top. New fluids and boom, started and ran without an issue and I figured I had gotten very lucky. Well... then I took it home from my employer's shop and the "short" light was illuminated. I didn't think much of it, figured it had to do with the lack of a battery at that point, and I had hand-started it.
Ran it again today... no joy for the first 15 minutes, then the unit started producing power, and happily ran a heat gun I had plugged into the convenience socket for the purpose of stripping the various stickers off of it. Trucked it home again tonight, back to the "short" light illuminated. The Battle Short switch makes no difference.
I'm all ears for a solution. Popping open the voltage selector switch switch cover shows some fuzzies and dirt in there, and I had to pull a sunflower seed husk out of the hole for the twist-lock when I first opened up the unit. The hardware on the back of the cabinet makes it appear that the inverter has been removed before as the bolts are missing paint. Other connections seem fine. I'm obviously not keen on buying another inverter and am hoping someone can help me chase this ghost short. Thanks to any who reply!
Ran it again today... no joy for the first 15 minutes, then the unit started producing power, and happily ran a heat gun I had plugged into the convenience socket for the purpose of stripping the various stickers off of it. Trucked it home again tonight, back to the "short" light illuminated. The Battle Short switch makes no difference.
I'm all ears for a solution. Popping open the voltage selector switch switch cover shows some fuzzies and dirt in there, and I had to pull a sunflower seed husk out of the hole for the twist-lock when I first opened up the unit. The hardware on the back of the cabinet makes it appear that the inverter has been removed before as the bolts are missing paint. Other connections seem fine. I'm obviously not keen on buying another inverter and am hoping someone can help me chase this ghost short. Thanks to any who reply!
Might be moisture. With the unit off, open the voltage switch cover and leave it open. Fire the unit up and let it run at high idle for 15-20 minutes. Shut it down manually, close the cover and the restart. See if that solved the problem. The overload circuit appears to be very sensitive to moisture and will give a simular complaint.
g2reeves
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Thank you, Cord. The unit rode around in my truck for a week after putting diesel in it and we got a bunch of rain, so moisture is possible... it just seemed to take forever to get it back to working.
A quick update: ran the unit 30+ minutes, no change, still "short." Left the cabinet open for 30-ish minutes, walked the dog around the block and came back, thought "what the heck" and gave it a pull. Started up, no lights, making power. Wicked buzz coming from behind the panel, found K15 very hot to the touch and full of steam. Shut down, moved relays around, tried again, immediate"short" light. Hm. Swapped relays again. Started up, no issues. The engine speed was now hunting like mad, so I locked it out with the manual start pin, found the power stable, 120 volts and humming happily. Plugged in my shop vac, pulled 1000 watts without a hiccup and otherwise happy.
So- a bit of progress. Thoughts on the relay situation? Each one has lights, two green and one red. Not sure if that matters. The speed control is another issue altogether that I'll tackle at another point. I noted another MEP-831A thread goes into fairly deep detail into getting that one set up right.
-G
A quick update: ran the unit 30+ minutes, no change, still "short." Left the cabinet open for 30-ish minutes, walked the dog around the block and came back, thought "what the heck" and gave it a pull. Started up, no lights, making power. Wicked buzz coming from behind the panel, found K15 very hot to the touch and full of steam. Shut down, moved relays around, tried again, immediate"short" light. Hm. Swapped relays again. Started up, no issues. The engine speed was now hunting like mad, so I locked it out with the manual start pin, found the power stable, 120 volts and humming happily. Plugged in my shop vac, pulled 1000 watts without a hiccup and otherwise happy.
So- a bit of progress. Thoughts on the relay situation? Each one has lights, two green and one red. Not sure if that matters. The speed control is another issue altogether that I'll tackle at another point. I noted another MEP-831A thread goes into fairly deep detail into getting that one set up right.
-G
Jay722
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I'm not sure if anyone is still on this thread, but I am having the same problem. The K15 relay is burning up every time I try to contact the load. After starting the generator there is a green light buzzing on the relay K15 and if I close the circuit interrupter it will burn up the relay. I have no idea why. I would appreciate any help!
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Partner, start a new thread. You get a much better exposure, more people will help.
Jay722
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I appreciate it, still trying to figure this site out.
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k15 relay is the starter lockout. Make sure relay is 120vac coil. Mine had been swapped around the other two ice cubes are 24vdc coils.
Jay722
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No it's a 24VDC relay and I just measured it and there is 120vac running through the coil and I wasn't sure if that was supposed to be there or not. So the K15 relay is supposed to be a 120vac coil?
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Yes relay is supposed to be 120vac coil. 120vac is what you will get back from inverter to prevent you from engaging starter after unit is running.
Jay722
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Awesome, that explains everything thank you so much!
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I attached link to TM on your other thread. It will have a nice buzz to the relay when you apply 120vac to 24vdc relay. 
Jay722
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Hahaha yeah that sure does make a lot of sense.