MEP-831 inverter troubleshooting

[dh1989]

Hello,

I have an MEP-831 which I bought about a year ago. It has worked flawlessly to date. I run test runs with a 50-75% variable load for an hour each month, and ran it for a 4 hr power outage last fall. It has never given my any problems. This month I brought it out of my shed for the monthly test and immediately noticed that the starter lockout wasn't working and that it would re-energize the starter with the engine running. I then went to close the circuit interrupter and the green light did not come on and the volt meter showed no voltage. The unit had worked perfectly for last months test when I shut it down and put it away.

I went through the manual troubleshooting procedures and found that I had no power at L1/L2 on the top of the inverter/converter unit. My first step was to open the voltage selector cover and run the engine for a half hour to heat the unit up. I read another thread where the inverter/converter was shutting down due to moisture and this helped. After 30 min I shut it down, closed the cover, and started it again. It still wouldn't produce voltage. I then tested the P15 and P16 connectors which are the outputs for the generator windings. I had 1.1 to 1.2 ohms resistance between the same numbered windings and no continuity between any different numbered windings. I started the unit and tested A1-C1, A2-C2, A3-C3, and A4-C4. All read 195-198 vAC. It appears based on this that the generator is fine but there is an issue with the inverter/converter unit. I removed and reconnected the P15-P16 connectors several times to make sure they were seated properly. I also looked at the wiring looms and didn't see any burnt up or obviously frayed wires.

I removed the inverter/converter unit and took the side covers off. I visually inspected the capacitors and circuit traces and couldn't find anything out of the ordinary. I read another thread about testing the soldered fuses (F1-F4 at J15/J16 terminals). I removed the varnish coating on the leads and tested each with a multimeter. I found continuity on all fuses, meaning no blown fuses. I then tested the voltage selector cover lockout switch. I showed continuity only when the switch closed, so it appears to be working properly.

Is there anyone who has dealt with this issue before who could point me to a specific component I might need to test or replace? This is the only generator I own so I would like to get it back in service in case I need it. Thanks for any help.

 

[BobbyT]

@kloppk is the 831 guru, he should be able to help you when he gets to see this post.

 

[BobbyT]

@kloppk is the 831 guru, he should be able to help you when he gets to see this post.

Forgot to mention, @Dewie38 is also a pro with the 831's.

 

[kloppk]

If the inverter is not outputting power the starter lockout will not function. The inverter output from N and L1 is what powers the coil in K15 the starter lockout relay. Without power from the inverter the starter lockout relay will not function.

Looks like you did some good troubleshooting to verify that the PMA is supplying power to the inverter. Based on your info it might appear your inverter has potentially failed.

Any Fault lamps illuminated when running?

What is the serial number of your 831?

 

[dh1989]

Any Fault lamps illuminated when running?

What is the serial number of your 831?

No fault lamps while running. The plate on the front says (S) FZA09427. It has a tier 2 reset plate which shows a new engine serial number and a date of 7-2013.

 

[dh1989]

I've gone through the inverter unit as much as I can and can't figure out what's wrong with it. I'm thinking about turning the set into a conventional generator. I would need to replace the generator head to a standard 120/240 60 hz one. I read that the Yanmar L70 engine has a J609B tapered crankshaft. I can't find a generator head that fits this. It looks like there was a Northstar unit that is no longer made. Does anyone have a source for a head that fits this engine?

 

[kloppk]

I've searched lately and haven't been able to find a suitable gen head with the J609B.

 

[dh1989]

I've searched lately and haven't been able to find a suitable gen head with the J609B.

I wonder if this would work? It lists J609B in the drop down for the tapered shaft application:

Mecc Alte Single-Bearing Generator - S15W-102, 3.4 kW, 120/240 Volt, Single-Phase, 3600 RPM

Mecc Alte Single-Bearing Generator - S15W-102, 3.4 kW, 120/240 Volt, Single-Phase, 3600 RPM Constructed of UL-compliant steel frames and shafts; Aluminum or Glass-reinforced Nylon fans 1800 RPM on almost all models 300% short circuit capability (per 20

www.absolutegenerators.com

 

[kloppk]

Looks like that one would work and fit. It's almost the same size as the Northern Tool gen head I have in one of my 831's.

 

[dh1989]

I might give it a go and order it. Could you fill me in on what you used for the 24v control power on the 831 you modified?

 

[kloppk]

I designed a special Governor Controller that maintains 60 Hz, restores the %Load function of the load meter for both legs and restores the overload function to open the contactor if either leg is overloaded. Let me know if you get the new gen head and are interested in the new controller.

 

[dh1989]

I designed a special Governor Controller that maintains 60 Hz, restores the %Load function of the load meter for both legs and restores the overload function to open the contactor if either leg is overloaded. Let me know if you get the new gen head and are interested in the new controller.

Thanks, that controller sounds great. I went ahead and ordered the generator head. I will let you know once I receive it and get everything bolted up.

 

[dh1989]

Stator is off and the armature crankshaft bolt removed but can't get the armature off. Any suggestions?

 

[kloppk]

Rotors on tapered shafts require a puller to get them off.
I had to fab up a puller to pop the PMA rotor off my 831 crankshaft. Basically made it from a heavy piece of plate steel with 3 holes in it.
The holes in the plate are not threaded.
Large center bolt is a 3/8 carriage bolt with a nut. The two smaller bolts are 1/4" that screw into the rotor.






Need to adjust the 3/8's nut so that when installed the 3/8" bolt is applying pressure on the end of the crankshaft. Tighten the two 1/4" bolts to apply the pressure. Once it's under pressure a couple of taps with a hammer on the head of the carriage bolt and the rotor pops off. It may also pop off just by tightening the two 1/4" bolts. I used grade 8's.
If you tap of the head of the 3/8" bolt be sure to be pulling the rotor away from the engine with your other hand before striking it.

 

[dh1989]

I was contacted regarding my generator head order today and informed the J609B style head is no longer manufactured. They stated the J609A is all that is available. It appears this style uses a significantly longer shaft design and wouldn't work.

I just located another J609B unit that appears the same but is rated 3000 RPM 50 hz. I'm wondering if I can use that and run it at 3600/60 hz.

 

[gstboy69]

Mep 831a Fault Help me!! Fuel Light

He have the fuel tank full. She starts great and then turn off automatic after 1 second and turn on in display the fuel light. If I hold the throttle with my hand the generator maintains on but after remove its turning off. Can I bypass this fuel alarm?

 

[Chainbreaker]

Mep 831a Fault Help me!! Fuel Light

He have the fuel tank full. She starts great and then turn off automatic after 1 second and turn on in display the fuel light. If I hold the throttle with my hand the generator maintains on but after remove its turning off. Can I bypass this fuel alarm?

Please do not duplicate (cross post) your question in multiple threads. This thread is is regarding "Inverter Troubleshooting" which has no relation to your issue. Your original thread has an answer with information that may help you resolve your immediate issue. If that answer does not help or you need further help please say so in your original thread. If you are in a Power Outage situation please say so, in your original thread, so that we understand if you have an urgent need for assistance.

 

[profo]

yall might want to check with Getec they are out of new york and make all sorts or belt drive and tappered shaft drive generators Hans has one that fits the L70 engine and prices are reasonable. I bought one of his hydraulic welder /generators and simply plugged it into my Freightliner See FLU-419 which outputs 180 amps dc welding and 10kw 120/240 vac , I also bought some J609b 3500 watt generators heads that bolt directly onto to L70 and if I remember correct they were around 400 bucks they are four wire ouptut and you can add a toggle switch to make it 120 only (parrellel winding) or 120/240 three wire (series windings) very simply. I think there was also a dc charging winding also. Been a few years!

 

[coxju04]

I was contacted regarding my generator head order today and informed the J609B style head is no longer manufactured. They stated the J609A is all that is available. It appears this style uses a significantly longer shaft design and wouldn't work.

I just located another J609B unit that appears the same but is rated 3000 RPM 50 hz. I'm wondering if I can use that and run it at 3600/60 hz.

I was wondering if you was able to find a Generator Head?

 

[profo]

Also there is a place in China called Werner Power that makes a complete inverter generator head that bolts directly onto the yanmar L70 also, you would remove the existing PMG and and inverter and just hook to the contacter, I tried to get a sample but the shipping on one was almost 400 bucks and the inverter/gen was only around 350.