How to convert Bach 44 ton from parallel to series?


E

Epimetheus

Member
Can someone post a description or link to a description how to wire the two tiny motors in series?

A Model Railroader mag in 2001 had an article how to wire the two motors in series in the older dual-motor Bachmann 44 ton loco. I do not have that issue.

Aside: I think the biggest problem is that both trucks have separate pickups, creating two one-truck locos. If there were jumper wires from one truck to the other, there would be 4-wheel pickup on both sides.

It's a cute little thing and I am determined to get it running smoothly.

Thanks much,
Doug
 
First you will have to isolate the motors from the frame to ensure the current travels through both motors before returning to the opposite track from the pickup track. Then, looking at your engine from one end, left pickup from nearest truck to left side of first motor, right side of first motor to left side of second motor, right side of second motor to right side of far truck. For 4 wheel pickup just wire the same side of both trucks together. If the motors turn in the wrong direction, reverse the pickup wires.
 
If you put two DC motors in series, there is one thing to understand. If they are free running -- let's say on 6-Volts -- and you grab the shaft and stall one of them, the other motor will speed up. THis is very easy to demonstrate with coreless DC motors like those I used to design large digital tape drives for early main-frame computers. This is because stalling the first motor kills the "back-EMF" and by series division of the voltage drops the second motor gets more voltage and therefore it speeds up. That is not perhaps a desirable thing.
 
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Charles, that is interesting.

Based on that new information I will start with a minimal change. Keep the motors in parallel and wiring the separate trucks' pick ups together - right to right and left to left. That will provide more pickup points for each motor and a longer pickup wheelbase.

The idea is to get the engine running more smoothly without entirely swapping the chassis, however that can be done.
-Doug
 
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