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Reply to "Using a PS1 Board Pullmor open frame AC motor: UPDATE: Success!"

Very cool experiment indeed!  I'm going to print this thread and save it because I had been meaning to explore these alternatives myself!  I think, five to six amps is abnormally high.  If it got much higher, you wouldn't be able to start the train at all.  For comparison, an unmodified 8551 would probably draw 2 amps cruising with that train, maybe spiking at 3 to 3.5 on initial acceleration.

I honestly wonder how Lionel arrived at the comparative resistance of the armature and field.  Bob Hannon compiled a must-have reference book on Lionel motors that would give you values for comparison.  These trains were toys for children so I'm guessing Lionel's priorities 70 years ago were cool running (for longevity) and plenty of RPM.  As an adult I like my trains to run slowly and accelerate realistically.  If performance improvements are possible from these old motors, what's a few amps between friends!?    

Slightly off-topic but I once installed a 3-position E-unit into a loco with a double-wound field  (needed for a 2-position e-unit.)  The instructions said to leave one field winding disconnected.  But I wondered what would happen if I connected both field windings in series, so I tried it. 

The performance didn't improve, but it got me thinking about whether better control could be obtained by exciting the armautre and field separately.  In fact, I wonder whether the Electric Rail Road (ERR) AC commander and some of the solid-state E-units that are purpose-built for AC motors (such as those by Dallee) use this very technique to achieve improved motor control?

One way to experiment with relative voltage for armature and field would be to use a pair of Lionel No. 95 rheostats in series with the rectified DC.  One in the armature circuit, and the other in the field circuit.  Eagerly following this thread!

Last edited by Ted S

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