Help! Can not get AC motor to reverse!

dennishOGR Forum Member

Evening!

I have an alco locomotive with an AC wire-wound motor and a new 2-position e-unit. The e-unit cycles, there is continuity and 18 ohm resistance across the coil. The motor has been cleaned and reassembled and wiring reattached correctly. Doubting myself, however, no matter what configuration I connect the field coil wires to the motor, I CANNOT get the motor to reverse! It will cycle through forward and neutral, but then goes back forward again. There is continuity through each wire on the field coil and about 2.6 ohms resistance, if I remember correctly.

Boy, some help/thoughts would be appreciated! I would even be OK if it was a simple thing that I am overlooking !

Incidentally, my friend wants an e-unit it the locomotive. Otherwise, I would just run it forward.

Thanks,

Dennis

1/15/248:38 PM

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harmonyardsOGR Forum Member SUPPORTING MEMBER

2 position e unit doesn’t have a neutral. They are only forward & reverse. Retrace your steps, what you’re calling neutral should be reverse. …..3 position has forward, neutral, & reverse.

Pat

1/15/248:56 PM

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dennishOGR Forum Member

Pat, Your are right! I knew that, but I didn't think of that !

But, I can't figure out why is it not reversing. It hums, but that darn armature doesn't rotate backwards!

1/15/248:59 PM

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dennishOGR Forum Member

Probably needs a Pittman !

1/15/249:00 PM

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MEDOGR Forum Member

The two pages on an Alco with 2 position E unit, and a page showing 2 position E unit.

There is a metal arm sticking up through top of shell that selects Forward-Neutral, or Reverse-Neutral (E unit used), mid position for direction lock.

Pages from Olsen CD.

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Files (3)

202UnionPacificPage1.pdf

202UnionPacificPage2.pdf

Lionel 2 Position E unit.pdf

1/15/249:02 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

You do realize that a 2-position E-Unit usually has a split field to work with, right? They don't reverse the armature like the standard E-Unit.

1/15/249:05 PM

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ADCX RobOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

@dennish posted:
...But, I can't figure out why is it not reversing. It hums, but that darn armature doesn't rotate backwards!

This nylon washer is probably missing:

This is not a ground connection, but is a strain relief mounting point for one of the field wires and it will run in only one direction if this is shorted to the motor or chassis. Here is the part number:

1/15/2411:05 PM

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dennishOGR Forum Member

Thanks, Rob! I have some on order, waiting for them to come in. I knew that was missing. I guess I forgot and was testing the unit without the nylon washer. Should be a few days and we will see. Thanks for the help.

1/16/245:53 AM

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ADCX RobOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER