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MEP-804A VOLTAGE REGULATION CIRCUIT QUESTION.

TheEquineFencer

TheEquineFencer

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I have a MEP-804A generator I'm trying to help a guy out with. It's connected 120/208. The symptoms are no AC output. I've noticed as long as the start switch is held, it has AC output, release it and it goes away. So I know the start disconnect circuit works along with the generator end itself. It's a control issue. So what's not picking up? Which terminals on the Voltage regulator should I have DC input to to hold it active?I'd love to know what each terminal on thr voltage regulator does what?
 
155mm

155mm

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Did you check magnetic pickup?

Have you tried bumping the start switch again after the engine is running? Also called modified start sequence.
 
TheEquineFencer

TheEquineFencer

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155mm said:
Did you check magnetic pickup?

Have you tried bumping the start switch again after the engine is running? Also called modified start sequence.
Click to expand...
No, I'll check the mag pickup. Where does it come out at on the control end? I'm going to "assume" it's run off the teeth on the flywheel. I'll try the "modified start sequence" in just a few minutes. BRB in a few and post the results.
 
TheEquineFencer

TheEquineFencer

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TheEquineFencer said:
No, I'll check the mag pickup. Where does it come out at on the control end? I'm going to "assume" it's run off the teeth on the flywheel. I'll try the "modified start sequence" in just a few minutes. BRB in a few and post the results.
Click to expand...

The "modified start sequence" yielded AC output at the correct voltage/Hz as long as start control was engaged, then both went to zero.

It'll take a few minutes to get to the Mag pickup and check voltage at the pickup.
 
TheEquineFencer

TheEquineFencer

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TheEquineFencer said:
The "modified start sequence" yielded AC output at the correct voltage/Hz as long as start control was engaged, then both went to zero.

It'll take a few minutes to get to the Mag pickup and check voltage at the pickup.
Click to expand...

2.3-2.7VAC during cranking, it will not run without the mag pickup connected from what it looks like.
 
155mm

155mm

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Correct, will not run without mpu connected. Mpu controls fuel actuator

did you check fuse by voltage regulator? Do not bypass fuse even for testing only.
 
TheEquineFencer

TheEquineFencer

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155mm said:
Also check big fuse next to voltage regulator behind control panel
Click to expand...

I'll check that ina minute. Doesn't that go to the F1-F2 going to the exciter? If so, it's got to be good because I have correct voltage/Hz when I hold the starter engaged after it runs?

Im starting to think the problem is the voltage regulator. If this thing works like I think it does, the starter cycle flashes the field, then the regulator is supposed to see AC output and start sendng volatge out to F1-F2 circuit. I don't think it's doing that.
 
TheEquineFencer

TheEquineFencer

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Guyfang said:
Buy two or three. If it blows again, you need to look into finding a A1 volt regulator.
Click to expand...
It puts out voltage like it should now. Thanks again!

Next week I'll cobble together a 3 phase load bank and test it....and get the right fuse...all they had were 10A fuses rated 250vac, it supposed to be a 3A 600V rated fuse.
 
Guyfang

Guyfang

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TheEquineFencer said:
Sorry, go start your own thread...yeah, I'm "that guy"...



Thanks again for the help, you're a good Joe!

BTW, I downloaded all available information on this unit I could find from here and a few other places.
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No need to be sorry, you did the right thing and maybe if I had looked closer, would have seen this post first. In any case, 155 got you straight. Now, about hitting those books...................................
 
TheEquineFencer

TheEquineFencer

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Guyfang said:
No need to be sorry, you did the right thing and maybe if I had looked closer, would have seen this post first. In any case, 155 got you straight. Now, about hitting those books...................................
Click to expand...
The retired Navy Master Chief I work for said that's a habit he's noticed with me...I may not make the most popular remarks or decisions, but I make the right ones. Then again, the retired Marine Captain I used to work for said about the same thing after I turned his lazy butt in for not reporting my suspicions of a fellow employee embezzling funds when I worked at Ryder Truck Rental. Something to the effect of "you strike me as the type of guy that would frag a CO." My reply was "I'm the type of guy that would walk in the room and sit down beside him and watch it go off to make sure I got the right guy." I'll sacrifice myself or what I have to help someone else.
 
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