MEP 003A Voltage / Phase Selectorl Box Diagnostics

[cuad4u]

I am trying to diagnose and hopefully repair a problem(s) with a spare voltage / phase selector box off a 003A. I have downloaded every TM that is available on this site. The spare voltage / phase selector box looks to be in great shape. It is clean inside, the the reconnect switch turns and indexes properly, all of the wiring looks pristine, but when I removed a working voltage / phase selector box from a working 003A and installed the spare voltage / phase selector box to check it out, I get no voltage at the convenience outlets or at lugs L1, L2, or L3. When I reinstalled the original voltage / phase selection box back on the working 003A generator, all is well.

The problem must be in the spare voltage / phase selection box.

Per the TM's I have removed and tested the bridge rectifier board. It is OK. I measured the resistance of the linear reactor windings. They are OK at 13.5 ohms. The next test suggested in the TM is to check the primary and secondary windings in the CT's by measuring resistance between certain terminals. The TM states to measure resistance between certain combinations of terminals H1, H2, H3, H4, H5, and H6. I have poured over all the TM's and the schematic for the better part of a week and for the life of me I cannot locate these terminals. Ditto for terminals X1, X2, and X3. Ditto for terminals C1 and C2.

Can some of you who are familiar with these generators point me to where these terminals are located so I can hopefully zero in on the problem?

Thanks in advance.

 

[Isaac-1]

I had the same problem trouble shooting a voltage problem and someone posted a diagram of the terminal layout, it is not logical to me. I will try to find a link and update this reply.

Ike

ps, note diagram is upside down when viewed from the access panel

here is the link http://www.steelsoldiers.com/showthread.php?112646-MEP-003a-CVT1-markings

 

[cuad4u]

Thanks Isaac-1

I have three 003A gens and two 002A gens. None of the CT's have any markings what-so-ever. Don't know where you got this info, but thanks.

 

[cuad4u]

Well everything checks out in my spare voltage / phase selection box, except it won't "work" when installed in a working 003A. The bridge rectifier board has been removed and ohmed out per the TM and OK. The linear reactor ohms out per the TM. The two CT's ohm out per the TM. The wiring looks pristine. The reconnect switch turns easily and indexes properly. The two circuit breakers ohm out properly when open and closed. Unless somebody changed some wires for spite just to make the next owner lost their religion, I cannot figure out what may be wrong.

Any experts out there have any other ideas as to what to look for?

 

[Speddmon]

Since you said the generator works with one box but not the other, I would suspect a wiring issue in the non working box. The field excitation wires go from the VR through the voltage / phase selector box and out to the gen head. Quite possibly one or both of those wires are not hooked up or are in the wrong spot. I would start there and follow those wires fully from the point where they enter the box to the point where the leave the voltage/phase selector box.

 

[cuad4u]

PROBLEM FOUND. Initially I tested the linear reactor in the circuit and got acceptable ohm readings. However today I started removing some of the major components in the box. When I removed the linear reactor it came out in two pieces and the plastic cover came out in about 4 pieces. When I ohmed it out on the bench with no wires attached two of the coils are open. The other coils read 13.5 ohms as the TM says they should. I guess the linear reactor is the problem.

Being rather new on this site I don't want to make any social blunders. I apologize in advance if the next question is out-of-order. I am looking for a working linear reactor or a non-working box with a decent linear reactor. I don't mind paying a fair price.

Thanks...........