Two position Lionel E unit wiring help

[rrswede]

I posted the following on another site and have not had a response. Would really appreciate a response from a member of this forum.

Am attempting to breathe some life in a Lionel 8042 locomotive that has a two position switch instead of a typical E unit. This locomotive was disassembled and left for dead by the previous owner.

The armature was cleaned and tested, the brushes and rest of the motor were cleaned, the two position switch relay was tested and after the motor was lubricated, it was wired using the attached link as a guide.

https://www.lionelsupport.com/media/...04Complete.pdf

A red and green field wire were twisted together and attached to one brush, the other end of the the red field wire was attached to one post on the two position switch, the other end of the green field wire was attached to the other post on the switch, and the pickup wire was spliced into a wire between the second brush and the two position switch coil.

When the track power was applied to the motor, it simply sat still and chattered.

I removed the motor from the track, disconnected the three wires (red field, green field and pickup/brush) from the two position switch, connected one transformer lead to the disconnected red field winding and the other lead to the pickup/brush wire. When power was applied, the motor ran. It also ran when the transformer lead was switched from the red field wire to the green.


Can you tell me where I went wrong in my wiring?

Thank you, swede

[TrainLarry]

Insure that the wiring follows the left-hand schematic for a motor using a two position reverse.

 

Larry

[rrswede]

Thank you for responding, Larry. I used that left hand schematic in conjunction with the link in my original post.

There are two red and two green field coil wires coming from the motor. One green and one red wire  are shorter than the the other two. Those two wires were twisted and soldered together at one time and their length is a perfect fit to be soldered to one brush. That is what I did.

I then soldered the other end of the green wire to the left side post protruding from the front of the "E" unit shown in your attachment and the other end of the red wire to the right side post. I then connected the pickup wire to the second brush as well as to the "E" unit coil post shown on the right side of your attachment.

When the assembled motor with that wiring is placed on the track and power is applied, the "E" unit hums, does not respond to a change in direction signal and the motor simply chatters.

As indicated in the original post, when I removed the motor from the track, disconnected the three wires (red field, green field and pickup/brush) from the two position switch (leaving the pickup wire portion connected to the brush), connected one transformer lead to the disconnected red field winding and the other lead to the pickup/brush wire and when power was applied, the motor ran. It also ran when the transformer lead was switched from the red field wire to the green.

I don't know what I could have done wrong. There is obviously some electrical glitch but I don't know what else to check.

Thanks, swede

 

 

[Firelock76]

It could very well be that E-unit's gone bad, it happens.  I have a Lionel 224 where the E-unit crashed, so I wired the pick-ups directly to the motor as you did and the motor worked perfectly.  The locomotive runs forward-only at this time but one day I'll replace the E-unit, but right now it's not high on my priority list.

[rrswede]

Thanks for the response, firelock.

With the "E" unit isolated, the plunger functions perfectly when power is applied across the coil and, when checked with an ohm meter between the output posts for the red and green field wires (one at a time) and the "E' unit ground, I read an open or continuity, depending on the cycle of the "E" unit. To me, that means it is functioning like it should. Am I mistaken?

Thank you, again, swede

[Firelock76]

Swede, you've got me there.  I would think it's functioning normally but obviously something's wrong when that E-unit's part of the circuit.

I think some more input's needed from the other's on the Forum.

The E-unit that I had go bad on me was a three-position one, and when it died there was no mistaking it, it threw a shower of sparks!  I can't claim any experience with two-postion E-units.  The only engine I've got with a two-position unit is on an old Marx 4-4-0, it's stuck in the forward-only position.  I decided to quit while I was ahead and left it alone.

[rrswede]

Thanks Firelock. I am not familiar with two position "E" units either but, based on working with this one, they seem much simpler than the three position ones. Of course, there is no neutral.

In documentation provided in this post, there are steps you can take to convert two position to three. I may do that just to see what happens.

Thank you and if there are more suggestions for me to explore, please provide them.

swede

[TrainLarry]

With all wires disconnected from the reverse unit, checking with an ohm meter you should get continuity between one lug of the reverse unit and ground with the plunger in one position, and get continuity between the other lug of the reverse unit and ground with the plunger in the opposite position.

 

Larry

[rrswede]

Larry, I do get continuity performing the check as you indicate.

swede

[TrainLarry]

If the motor is good, and the reverse unit checks good, and the wiring is  correct between the motor and reverse unit, then there seems to be no  reason the motor does not run when hooked up to the reverse unit.

Is the reverse unit free of any corrosion and making a clean, solid connection to chassis ground? 

With the motor powered up, check for voltage from the pickups to the brushes, and through one field coil and one position of the reverse unit, and then check the other field coil through the other position of the reverse unit. There should be no voltage drops anywhere in the electrical path.

 

Larry

[cwburfle]

When a motor with a double wound field hums or vibrates as you describe it usually means that both windings are energized at the same time.

[rrswede]

Larry, the "E" unit is really clean and cycles perfectly. As of the voltage checks, I have not performed them but, if I must, I will. I have refrained from doing so for fear that prolonged chattering of the motor while performing the checks will be harmful.

cw, I am in agreement with you but, for the life of me, can't figure out where the wiring error is being introduced.

I'm on my way to church right now but will tinker with the motor when I get back.

By the way, I removed the "E" unit and connected the motor to operate in the forward mode, only, and let it run on the track for about 10 minutes without a hiccup.

swede

[cwburfle]

Sorry for the incomplete thought earlier.

I beleive that you have already verified that the e-unit was only grounding one terminal at a time.
That leaves your wires themselves. I would look for places where the wires from the motor to the e-unit are touching something metal. The wires do have insulation on them, but you may have a wire touching where the insulation is either damaged, or was intentionally removed.

Did you write that the e-unit wouldn't cycle when installed?

[rrswede]

Thanks for the response, cw. Did not get a chance to get back to the computer till now and have not touched the motor.

Yes, the "E" unit correctly grounds one terminal at a time and no, the "E" unit has cycled perfectly from the get go.

Perhaps this evening I will be able to look at each wire, again, to see if I spot wire damage. Who knows? Some of the grand kids have been here since before lunch and will be here till their parents pick them up tomorrow. I know the cloth/fiber insulation is heavily frayed but I have been trying to keep each wire separated from the other.

swede

 

[rrswede]

CW, Larry and members

While the grandkids were occupied, I got a chance to look at the motor, again.

With the "E" unit detached from the motor, I isolated each of the motor field  windings ( two red and two green) as well as the pickup wire. I checked for continuity between the two ends of the red and two ends of the green as well as for an open between the red and green and all was proper. Instead of stopping there, as I had previously done, I also checked for an open between the green wire and motor frame and the red wire to motor frame. The green wire checked out ok but the red wire is shorted to the frame and therein lies the problem.

Tomorrow, I will take the next step to correct the problem

Thank you, swede

[Firelock76]

Brilliant!  Let us know how it turns out.

[rrswede]

Firelock, Larry, CW,

I pulled the wheels, separated the side frames leaving the motor field assembly attached to one side frame and checked to see if there was an open circuit between the side frame and the green and the red field wires. As before, the green wire to side frame showed an open circuit and, still, a connection between the red wire and side frame.

I then removed the motor field assembly from the side frame, removed the protective tape from the field coil and checked for damage to the wires. There was no evidence of damage. 

 I then checked each wire against the stationary field. This time both wires showed an open circuit.

After wrapping the field coil with fresh tape and reassembling the side frames and motor field assembly, electrical checks proved to be successful.

I am very please to report that the motor is now fully assembled and operational.

Thanks everyone, swede

 

[Firelock76]

Great news!  Well done!

[markoles]

Hi Swede,

Thank you for posting this question! I have an old Lionel 4-4-2 that has one of these two position reversing units in it.  The engine only runs in reverse, and I think it is because the E unit does not have its ground wire hooked up. There was a loose white wire in the engine when I took it apart last night. I believe, based on the wiring diagrams, that I need to re-attach this wire to the base of the e-unit, correct?