MEP-003A - Lost Output

[glcaines]

A friend came by today and wanted to see my MEP-003A run as he is considering buying one himself. It was approximately 19 deg F outside and he was also concerned about starting one in the cold weather. After pre-heating the glow plugs, the genset fired right up, no problems starting in the cold temperatures. Unfortunately, that's where the good news ends. The genset now has zero output. The engine runs fine, the alternator charges the batteries, but no high voltage output. Frequency gauge reads minimal as well as voltage gauge. After reading the TM, I'm going to troubleshoot the regulator board, but it is too cold outside at present. I have had zero problems up until now.

 

[DieselBob]

Good luck on the troubleshooting. Most of the parts on the VR are available. There was a few of the capacitors that I was having trouble finding but I didn't look into it to far.

 

[Carl_in_NH]

Automatic field flashing inop? I forget if there's a manual flash switch in the 003A; I'll have to look a the TM for that information.

EDIT: Place the master switch in the START position once the generator is up and running at rated RPM to manually flash the field.

Give that a go and see if it yields any joy.

 

[Speddmon]

Automatic field flashing inop? I forget if there's a manual flash switch in the 003A; I'll have to look a the TM for that information.

Yes, there is a manual field flash. Just turn the main switch to "start" for a few seconds after the set is running. I would try that before I start digging into the VR.

But like Bob said...if the VR is the trouble, I'm pretty sure every component is available for it. Just need to know where to look.

 

[coyotegray]

When you get to the point of needing them, I have ordered parts from Delks with very good results...

 

[glcaines]

I'll try manually flashing the genset tomorrow morning and see what happens. One interesting fact, which I didn't mention, is that everytime I have started it in the past the gauges showed zero output for about 5 seconds and then the output started. I don't know if this is normal or not or was a precursor of future problems.

 

[Speddmon]

Mine start showing output right away, no delays. The TM actually does a pretty good job of narrowing down potential problems. But I would be curious to see if the field flash does anything for it.

 

[ncduece]

i am going to say its the rotating diodes on the armature. when the vr goes bad these sets produces over voltage, check the web site sparks and arcs good info there

 

[DieselBob]

Good point. When my CVT opened the “C” coils rendering the VR inoperative the voltage went up to 170Vac and 330Vac.

 

[Carl_in_NH]

Multiple failure modes for the VR are quite possible – some, like a shorted output transistor – will produce over-voltage output. Other failures, like an open output transistor, should produce no (or very low) output voltage from the generator.

While having a failed-shorted output transistor with high output voltage is more common, check the things that are easy to work on before going after things that require much more effort – like the rotating diodes.

Also be certain to check all electrical connections – both in the control cubicle and throughout the harness and any circular connectors. Grungy connections are common sources of flakey operation – like not producing power for several seconds until the vibration helps them regain sound contact.

 

[glcaines]

Well, I now have more information. I started the genset today and again zero output. I manually flashed and again no output. I flashed it five more times and got output, but high voltage. The lowest I can adjust the voltage now is 136 - 138 / 272 - 276 VAC. The voltage continuously fluctuates. This is all with no load. I put a stable 15 amp load on it and no difference for the voltages. It will adjust about 5 volts higher, but not lower. I confirmed all of the voltage readings with a DVM, which agreed perfectly with the meter on the console. I checked for loose wires and signs of overheating, etc. but could not see anything obviously wrong. I'm going to go through the TM and check out the VR, both onboard and offboard if necessary.

 

[Carl_in_NH]

I think you're on the right track; sing out if there's anything we can do to help with debug and diagnosis of the VR.

 

[Speddmon]

Gary,

I agree with Carl, it sounds like you're heading in the right direction now. The TM has a fairly simple "out of the unit" test circuit you can construct to test the VR. But you'll need a power supply to build it. If you can find the components/parts the testing procedure is pretty straight forward.

Good luck, and let us Know if you need any assistance.

 

[glcaines]

I'm probably going to wait 2 -3 weeks, until the weather warms up here. I have power supplies and test equipment, so that won't be a problem. I'm still in the process of wiring up the transfer switch and running the conduit to where the genset will be stationed. The 400-amp 4-pole manual transfer switch is now mounted on the side of the house, but I have to run 2-inch conduit 125 feet to the genset and the conduit needs to be buried 18 inches. Not a problem with a trencher, but the area is confined in some places. I've got the area torn up and I need to complete the conduit run to keep my wife happy. I've also got my Wisconsin Robin 3kw genset torn apart - no fuel from injection pump. Too many hobbies.

 

[jbk]

gary mine would fluctuate also. the tm said the problem was with a pot on the vr board. adjusting it did nothing. long story short turned out to be a cold solider joint on the vr board. i had to solder quite a few. look for a blackish circle inside of the solder joint. i had several. i believe was caused from vibration. took a couple of times but works fine now. and look at these joints were the pot is soldered.

 

[glcaines]

gary mine would fluctuate also. the tm said the problem was with a pot on the vr board. adjusting it did nothing. long story short turned out to be a cold solider joint on the vr board. i had to solder quite a few. look for a blackish circle inside of the solder joint. i had several. i believe was caused from vibration. took a couple of times but works fine now. and look at these joints were the pot is soldered.

Did you also have high voltage like I'm having? I'll look for the cold solder joints. Thanks.

 

[jbk]

yes mine would fluctuate between 119 to 136 volts up and down . i used a hot iron you dont have to woory about the coating it will burn off. remove the board and look real good under a good light and magnifiy if possible. i think the joints related to this pot were the problem i did these the second time and have had no issues since. dont give up on the board yet.

 

[glcaines]

Too Cold to Work On GenSet!

This is why I'm waiting for warmer weather to work on the GenSet! We got another six inches of snow today.

 

[DieselBob]

Nice trailer setup. I need to get myself one of those. Good luck on the troubleshooting and the warmer weather

 

[Speddmon]

This is why I'm waiting for warmer weather to work on the GenSet! We got another six inches of snow today.

I don't blame you...working in the snow sucks. At least we have global warming to thank for such a mild winter

Keep us posted on your progress, and the repair especially.