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Military MEP and Aircraft Gen-Sets MEP Mobile Electric Power, APU Auxiliary Power Unit and other military surplus generators.

Military MEP and Aircraft Gen-Sets

MEP-002A Low Voltage


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  #1  
Old 07-21-2013, 09:30:15 PM
marvgarr marvgarr is offline
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Default MEP-002A Low Voltage

Ok so I am having a tough time with this unit. I get half voltages across output terminal block no matter what position reconnect switch is in. I get 60 volts were I should have 120 and I get 120 were 240 should be. The front 120 recpt has 60 volts also. I have checked the rectifier board and resistor ohms are 55. I checked cv1 and ctv1 it ohms out right also. When I flash it I get the right voltage I had my dad check the vr board he said it was good. With a load on it the x1,x2,and x3 put voltage out to rectifier board. C1 and c2 have only 7-8 volts to them out of voltage regulator. Both t1 and t2 are putting out voltage with out flashing and low voltage t1 puts out 12v and t2 puts out 22v unknown what the specs are. Voltage to the field is 8v with no flashing and 10 volts with flashing. It has 60hz but with a high load I can't read Hz just goes high triple digit high. I tried to adjust regulator it made no difference. How do you test the regulator so if it is bad I can repair it. One more thing behind cvt1 and ct1 there is a black box has 6 terminals on it's only about 1 1/2" wide 3" tall what is it?
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  #2  
Old 07-24-2013, 04:48:40 PM
marvgarr marvgarr is offline
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Default Re: mep-002a low voltage

Someone has to have some idea. Maybe how to test regulator a different way from tm manual?
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Old 07-24-2013, 05:08:04 PM
Roland Hayes Roland Hayes is offline
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Default Re: mep-002a low voltage

If your alternator has diodes or a rectifier to convert AC to DC for the excitation current, one of the diodes or rectifiers may have blown, when this happens on a 2 pole alternator half the excitation current is lost leading to a loss of half the output voltage/current similar to what you describe. Is there any diodes on the rotor of your alternator or does it have slip rings and a rectifier, you need to carefully check all diodes or rectifiers for failures or partial failures.
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Old 07-24-2013, 08:41:48 PM
marvgarr marvgarr is offline
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Default Re: mep-002a low voltage

Well its a four pole alternator I'm just not getting proper voltage for the exciter. I was hopeing someone knew how to test the regulator easily.
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Old 07-25-2013, 09:24:10 AM
Richard L Richard L is offline
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Default Re: mep-002a low voltage

You need the transformers indicated to test the regulator. If you have voltage when you hold the flash switch over then the gen end is good, and the problem is with the reg circuit.
Also you can open the output box and on the right hand side there is a terminal board,TB3, Disconnect the wire from TB5&6 and apply 12 volts, again if you have voltage then the end is OK.
What BOX?? are you talking about?
Re the regulator, call Brian Clugson at Flight systems,I believe they can repair ir.
Stay away from Gulf Coast Trucks,as it turns out the guy is less than honorable to deal with, and you will never see your parts again.
I have several regulators from sets I converted to new style regulators.
Give me a call if you need some help
Rick
206-284-1848
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  #6  
Old 07-25-2013, 10:53:27 AM
Richard L Richard L is offline
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Default Re: mep-002a low voltage

I think what you are talking about is the reactor, which is part of the regulation circuit,These have been known to go bad,but rarely.
R
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Old 07-25-2013, 05:40:21 PM
marvgarr marvgarr is offline
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Default Re: mep-002a low voltage

Thanks for your input guys. I'm not sure what the box is. There is also no markings on it or around it like there other parts. Well I did some reading from old posts on mep-003's and found some good info. I found out that the regulator puts out small current to the cvt transformer. I also found that if no current is put to the cvt that the voltage will go high. I then pulled off #14 wire from reg and started unit I now have full power. I have 150v from l1 and l2 when switched to 120v output. I have 300v from l1 and l3 when switched to 240v and I have 150v from l1 an l0 and 150v from l3 ad l0. The unit is working so I know its the regulator. I read that the q3 transistor will go full continuous and cause the full power to the cvt. Is this all that will be bad? What about the q1 and q2 transistors should I replace them? I can repair this regulator myself as long as I know what's bad.
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Old 02-15-2017, 12:56:23 PM
fiddleyjon fiddleyjon is offline
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Default Re: mep-002a low voltage

does anyone have a cvt1 for sale for a mep002a. that would be the 72-5177 current transformer.
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Old 02-18-2017, 03:14:30 PM
Richard L Richard L is offline
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Default Re: MEP-002A Low Voltage

Just took 4 to the dump, call William at Delks army Navy and he should be able to fix you up. I have a new power output box, parts for these sets are getting hard to find
Rick
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Old 02-18-2017, 03:47:06 PM
Vanman Vanman is offline
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Default Re: MEP-002A Low Voltage

"Just took 4 to the dump" ... "parts for these sets are getting hard to find"

Huh. I wonder why....
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Old 09-30-2017, 08:51:00 AM
rleonard rleonard is offline
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Default Re: MEP-002A Low Voltage

I have some parts.

email me.

Bob
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