Need help with disposition of cut wire on MEP002A

[1800 Diesel]

Tonight I discovered a cut wire on one of our MEP002A units. This is the same unit that I'm troubleshooting the DC charging system, but from what I can tell, this wire is related to the AC side as the attached photos will show.

The wire in question is cut 1" outside the rear of J-2 (rear of the control panel box). I compared wire counts on an adjacent unit and found 20 wires heading into J-11 at the lower/rear of the AC control box. On this unit, only 19 wires were found & I located the cut wire at the rear of J-11..see photo.

Inside the control panel box I located what I believe the "surviving section" of wire # X35C16 and it connects to the ammeter-voltmeter transfer switch at what appears to be terminal 53. In checking continuity from the cut wire at the rear of J-2 (outside the control panel box) I get good reading on terminal 53 and several other adjacent connections. Note that the 4th photo incorrectly labels the switch as "voltage selector switch". Obviously the correct label should be "ammeter-voltmeter transfer switch"....still learning from reading TM...

So finally my question: Should I replace the missing section of wire? Should I leave it alone, assuming it was cut for a reason?

The unit is functioning properly with good output and all gauges/meters functioning properly. Possibly this wire is related to the 3-phase side which I don't need on this unit.

Thanks for any help or advice offered.

 

[Isaac-1]

I am wondering if you have a MEP-112a (400 Hz 10KW) control box that has been retrofitted to a MEP-002a, check and see which model voltage regulator you have. I know there are some slight wiring differences between the two, and I think I remember one of those differences being in the voltage selector switch, therefore you may have a MEP-112a control box that someone altered the wiring in to make it match the MEP-002a wiring diagram.

Ike

p.s. it is somewhat common to find the 400 Hz MEP-112a voltage regulators and control boxes in recently rebuilt the MEP-002a's they work fine and it seems the army had a surplus of them and started using them in MEP-002a rebuilds a few years ago, the only issue that tends to come up is trouble shooting when the wiring diagram your using does not match the box exactly.

 

[LuckyDog]

The cut wire is only used when in three phase mode.

I'd splice with some good 16AWG wire. It connects to CB1 also, so it is a safety thing if someone ever tries to use the unit in 120V/208V 3ph.

 

[1800 Diesel]

Ike,

I'll take a look at the VR to record a model # or other identifying nomenclature...if possible will shoot a photo. Thanks.

 

[1800 Diesel]

The cut wire is only used when in three phase mode.

I'd splice with some good 16AWG wire. It connects to CB1 also, so it is a safety thing if someone ever tries to use the unit in 120V/208V 3ph.

Luckydog,

I see the wire in question on the diagram but am not clear where I would add a connection to CB1. I see over to the left where CB1 is but not sure where I would actually make the connection with an additional wire.


BTW, I'll be editing my original post wrt the nomenclature of the switch that I called "voltage selector switch" that in the TM is identified as "ammeter-voltmeter transfer switch", which now I understand is provided for the gauges to read correctly depending on voltage selected by the reconnection switch. Also, on this particular unit the reconnection switch seems to be stuck if I try to rotate it CCW, though I can rotate it a small amount CW and can feel it stop but the spring returns to to more or less a "3-o'clock" position for single phase. Not wanting to damage this expensive switch, I'm reluctant to force it to a 3-phase setting and for that reason I thinking I shouldn't bother with replacing the missing wires. Seems like the only problem that would arise (if someone was able to position the reconnection switch to 3-phase), the voltage meter or ammeter wouldn't read correctly--is that a correct assumption?

 

[LuckyDog]

Sorry for the confusion....

I was looking at the butt-splices in pictures 1 & 2. That is where I would put the wire splices. (Or, if you know how and have parts, fix P2 and P11)
If you connect the two ends at the shown butt-splices, you are all set for 3 phase power.

As for the stuck switch, there are some posts about that. Don't have links, but I know they are there.

 

[1800 Diesel]

Sorry for the confusion....

I was looking at the butt-splices in pictures 1 & 2. That is where I would put the wire splices. (Or, if you know how and have parts, fix P2 and P11)
If you connect the two ends at the shown butt-splices, you are all set for 3 phase power.

As for the stuck switch, there are some posts about that. Don't have links, but I know they are there.

Thanks--just for info--I placed the red butt connectors on the cut ends just to help see the end of the wires better in the photos. My old digital camera wasn't too great in the close-up shots but the one I have now provides some good shots.

Back to the "lost wire"--basically if I inserted a replacement section of wire from the J-2 location to the J-11 location, it looks like the unit would be back to normal.

I'll check out other posts about the reconnect switch to learn about cleaning/freeing up...thanks again and have a good day/week.