MEP 003a back together...but...

[Speddmon]

I would like to see the physical difference you are talking about, because they are the same board. Both have the same NSN, and same P/N. Electrically they should be exactly the same as well. Maybe you saw an older style vs. a newer style. They did make a design change somewhere along the way, but it didn't change anything electrically, they are still interchangeable.

 

[RichardR]

Speddmon,

There really are two slightly different versions of the AC voltage regulator card you may find in either an MEP-002A or an MEP-003A. One is P/N 72-5020 and the other is P/N 72-5338. But they are physically interchangeable, and seem to work the same despite the addition of a few diodes in the 72-5338 version. Perhaps these are the old and new versions you refer to. My guess is that 72-5338 is the new version.

One of the TMs implies that one is for 60 Hz and the other is for 400 Hz, but I have seen both versions in 60 Hz gennys, and have interchanged them while troubleshooting without any effect. The TMs aren't real clear about which is the "right", or preferred version.

Regards,
Richard

 

[storeman]

http://www.steelsoldiers.com/auxiliary-equipment/79378-anyone-know-what-vr-board-fits.html

I posted this several months ago to illustrate the differences. If interchangeable, good news.

 

[Speddmon]

Jerry,

Keith answered your question pretty well in the thread you posted about the board differences. That also explains why (more than likely) the OP had put a board form an MEP-002a into his 003a and it burned up. The board out of the 112a will work, but NOT for very long inside the 003a due to the increased field current. My guess is that the OP had one of the 400 Hz boards inside of his -002a control box. When he put it in the 003a, a little bit into the test run the magic smoke was let out of it. This is the same reason you NEVER want to idle your generator. The VR will pump up the field current to it's maximum to try to get the voltage up, and will eventually burn up the VR.

Up to what RichardR posted, there is really only one regulator board for the 60 Hz MEP-002a and MEP-003a. The other board and part number he posted is for the MEP-112a 400 Hz genny. I would NOT use it in the 003a. You could get by on an 002a, but if you have both generators and do any amount of parts swapping, sooner or later you are going to forget and put that 400 Hz board in the 003a, and it will not be working for a long time.

 

[storeman]

SO, which board is the correct one for the 002a/003a?

Diesel Bob said "The board labeled 72-5338 is listed for a 400hz unit.

REGULATOR,VOLTAGE - 400 HZ
72-5338 (30554)
332-2285 (44940)


The 72-5020 is for a 60hz unit.

REGULATOR, VOLTAGE-60 HZ
72-5020 (30554)
WebFLIS search on the 72-5338 came up with

NSN: 6110010957440 [FONT=Verdana, Arial, Helvetica, sans-serif] Item Name:[/FONT] REGULATOR,VOLTAGE Query Type: PUBLIC Date of query: 12/11/2011 10:07:53 PM
SPECIAL FEATURESUSE ON ENGINE MODEL MEP-112A,DED GENERATOR SET,NSN6115-00-465-1027"



ALL of the ten 002a's I have had are equipped with this board, the 72-5338, and work well. Only one Mep-003a had the 72-5020.

Still confusing to me.

Jerry

 

[Speddmon]

The 60 Hz board is the correct board for the MEP-002a and MEP-003a, Part # 72-5020

 

[storeman]

Now I understand.

 

[Speddmon]

You posted a link just a few posts up...didn't you read your own thread ? Keith answered that question in the other thread. Answer

 

[hedgehog69]

Yes, that is the NSN for the DC regulator which is located under the cooling fan shroud. Again, it's not the DC regulator that will be damaged by idling the engine. The AC regulator does not like to have the engine at idle.

I was not getting any charge to the batteries. I swapped in a new DC regulator today and now batteries are getting a charge. This is the 2nd one I have had to replace in a 'fresh' rebuilt Melton engine.

 

[hedgehog69]

Learning continues...arrgghhh... working on getting the Starter Lockout Switch adjusted. I followed the directions f. Got adjusting screw adjusted as instructed....started engine...diconnected wiring harness and adjusted set screw at .040. Turned unit off...reconnected wiring harness. I attempted to start unit and only got solenoid click. Reset adjusting screw so contact was made...unit fired right up. I had also hoped that when this was adjusted correctly, the control knob would shut unit off when turned to OFF position. Always welcoming knowledge!! Digging into manual deeper.....