Voltage regulator MEP002a alternative?

[hedgehog69]

Doing research, I have found that the VR for the 002a & 003a are no longer available. Seems I am having issues with the battery charging system...and it seems to point to faulty VR.
Is there an 'aftermarket' VR that will work on these units? I am getting ready to take one of the gensets to a local Electric Motor shop that has much knowledge and experience....for testing. It is seeming very odd that 3-4 of my gensets are all suffering from the same problem...even the one with the fresh rebuild that I swapped in.

 

[Keith_J]

Have you run through the troubleshooting section of the TMs? First, check the fuse near the starter cut-out, above the oil filter.

There were a few spares floating around but they were going for a few hundred. I would swap in a 24 volt solar battery charging regulator, probably under $50 (10 amp model would be fine). But this is something you would have to design in, after verifying proper polarity of the leads.

 

[DieselBob]

Seems I am having issues with the battery charging system...and it seems to point to faulty VR.

The VR for the battery charge circuit is available. Just had to change mine because it would over charge the batteries.

Voltage Regulator/Rectifier (Battery Charging) For Onan MEP-002A / MEP-003A 5KW and 10KW Generator Sets, FVR4006

 

[hedgehog69]

Thanks...I have checked all the fuses. They are good. I don't have testing equipment, so I need to take gen and the manual to someone that does. I want them to do it while I watch...hoping I can learn something.

 

[hedgehog69]

The VR for the battery charge circuit is available. Just had to change mine because it would over charge the batteries.

Voltage Regulator/Rectifier (Battery Charging) For Onan MEP-002A / MEP-003A 5KW and 10KW Generator Sets, FVR4006

Thanks!! I search a while back and found nothing.

 

[coyote62ny]

try tom at gulf coast trucks reasonable prices garenteed used parts office number is 1-281-422-3200 cell 1-832-323-1445 as for testing very simple remove blower shroud disconnect vr wires from terminal strip have a good volt meter or multi meter set to ac volts start the gen set run at 60 hertz test the two wires that come from the stator you should get 30 to 35 volts ac between the two wires if you get this voltage the vr is your problem CAUTION DONT RUN THE GEN SET MORE THAN 3 MINUTES WITH THE BLOWER SHROUD REMOVED you will over heat the engine hope this helps you get them going i got a new vr from southern automotive on ebay they made this vr phone number is 1-248-335-5555 the one i got wasnt cheap 145.00 new with shipping tom would most likly have used ones delks surplus also had vrs but pricey delks number is 1-336-629-0991 good luck let us know how you make out getting them going

 

[hedgehog69]

WELL...THE LEARNING EXPERIENCE continues. I bought a tester and have been checking things with the old VR in place. Not much coming out the top side. Also...for whatever it is worth, this engine is a fresh rebuild I bought last year from Mechanicsburg, PA. THE Unit came with the IP missing, so I thought I would just do an engine swap.
So...30v+ coming from stator. I installed a NEW VR I bought from Southern Automotive for $150...thinking alright...away we go. Stiill not charging the batteries. I continue to research, but thinking there has to be something simple I am missing. The batteries take and hold a charge from my charger, so I don't think batteries are the problem.

 

[PeterD]

Here's a question for the MEP-002/3 experts? It appears to me that the battery charging regulator is a 'post' regulator that takes a (higher) AC voltage and rectifies and regulates it, right?

Would there be a market for an aftermarket designed regulator if that's the fact? Creating a 27.5-28 volt regulated power supply to charge the batteries would not be that difficult. In fact, a small hand full of parts is all it would take!

 

[Keith_J]

Precisely, Peter. I believe the original regulator is a shunt type, single phase linear regulator. The field of this alternator is a permanent magnet type, meaning voltage output is highly dependent on engine speed. Running the engine at lower speed can damage the regulator.

Although I'm against designing to be "idiot proof", some tolerance here must be made for starting and stopping.

 

[hedgehog69]

Well....going to tinker some more over Christmas vacation. Been studying the manual, so will try testing again. If my efforts fail, I plan to take it to Electric Motors and let the pros check it out.

 

[m38inmaine]

I had the same problem with my 003A, it turned out to be a bad battery. When I had it hooked up to my shop truck with the slave cable the battery charging system worked fine, as soon as I unhooked it the voltage jumped past 30v. Double check your batteries.

 

[derf]

If you read 28 or so Volts across the batteries when the gen is running then the charging system is working.
If you get 28 or so at the reg and not at the batteries then something is wrong between.
You should get 30-50 or something higher than 28 Volts AC at the stator output. The reg should make that 28-30 or so DC Volts.

 

[hedgehog69]

If you read 28 or so Volts across the batteries when the gen is running then the charging system is working.
If you get 28 or so at the reg and not at the batteries then something is wrong between.
You should get 30-50 or something higher than 28 Volts AC at the stator output. The reg should make that 28-30 or so DC Volts.

mORE testing today...with NEW batteries!! Needle on charging guage still in the yellow. I have 40v ac coming out of stator. I do get about 25v across batteries..running or not
With stator leads unhooked from the block, I am getting about 40v ac. Testing with leads connected to the block, I am getting about 16v. At the fuse I am getting about 16vdc. This is a new VR....hopefully not a lemon out of the box!!
I waste no time getting unit up to speed.
Makes it hard to test when you can only run unit for 3 minutes without the shroud...arrgghhhhh

 

[coyote62ny]

with the vr disconnected from the terminal strip [the wires that hook to the stator wires] you should get 30 to 35 volts a.c if you are not getting 30 to 35 volts a.c you most likly have a problem with wiring or the stator 40 volts a.c from the stator is 5 to 10 volts higher than the tm says is your genset running at 60 hertz when you are testing are you testing with the multi meter set to ac volts ?

 

[storeman]

I don't understand the stator's function. Apparently you can get good AC from the generator while having a bad stator. Does it have any other role than to provide AC for conversion to Dc for battery charging?
Jerry

 

[O.D. Fever]

From what I undestand there is a low voltage winding in the stator that is rectified and regulated for the 24 vdc circut.Its a relitivly low current (small wire size winding) If you run these rigs with shorted batterys or no battery you will fry the charging circut. If you are slave starting off of a truck with no batts. you must leave the truck attached, if the batts are bad you may also fry it. That may be why you have 3 with the same problems.

 

[storeman]

I have one with a problem, not 3. And, my batteries are good. That is why I'm a bit stumped.
Merry Christmas.

 

[hedgehog69]

I have one with a problem, not 3. And, my batteries are good. That is why I'm a bit stumped.
Merry Christmas.

I just tested the stator leads...app. 43v ac. I hooked them back to the block and tested..got about 27.5v ac. Guess I wonder where 16v is going to right off the block.??

I tested for dc voltage at the top...I only get about 2.6v. I haven't soldered wires back to fuse yet.

More testing results to come...

 

[coyote62ny]

the fuse wires have to be connected for the regulator to work . you should test the terminal block and make shure you have continuity through the block there shouldnt be any resistance between the screws in other words like touching the probs of your meter together. when testing the stator un hook the voltage wires from the terminal strip and test those two screws meter leads one lead to each screw. not each screw to ground. with the stator leads disconnected from the terminal block you should get an ohm reading of approximately 0.6 ohms if you get an open reading you have a wire touching the engine or blower wheel or a bad stator also check each stator lead to ground if continuity is found you have a bad stator . it will not charge if the fuse holder is not hooked up to the wires and soldered and of corse you must also have a good fuse. the only thing this stator and regulator do is to charge the batteries it has nothing to do with the a.c generator . also check the terminal strip and make shure you have no continuity to ground from the screws in the terminal block with the all wires disconnected and the terminal block left mounted to the engine.if i was closer i would help you get it straightened out . hope this helps you get it going what i have just posted is from the tm5-6115-585-12 change dated july 1977 this is the tm for the mep-003a but the same parts

 

[storeman]

Thanks coyote. I hadn't thought about testing the terminal strip.
Jerry