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Hi..

 

I am trying to figure out a weird quirk with a pullmore motor from the MPC lionel era. I have cleaned the commutator and replaced the brushes and lubricated it.  Here is the problem

while not on the rails

in one direction (forward) the motor and wheels spin nicely,

in the other direction, there is a slight hesitation and random slowing of the wheels. 

 

Now in reverse, it is "acceptable"  but not right. 

 

this motor frame has the round doughnut style pickups, and there are two plastic halves that come together. While the motor is running in reverse and the wheels are slowing I notice that one of the halves of the plastic frame is vibrating.  As if it is loose. 

 

any help is appreciated

 

Bill

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Marty thats what I figured... I didn't know if there was a "trick" that my peers have learned.  It is kind of a bizarre scene on my bench... I have two of these motor and frames to service.. and waiting in line are a pair of beautiful 773 Hudsons... one in black the other a 773e gunmetal grey..  I must say.. those Lionel Hudsons are a work of art!

Did you change the brush springs too?

Some guys soldered the short end of the spring to the brush holder for better contact. If it has a set screw on top adjust the up/down of the armature so it has just minimal movement.

That is an early MPC motor and was troublesome. The later motor ran much better but suffered from off center wheel wobble.

Last edited by Jim 1939
Originally Posted by bbsfdl60:

i was just given the frame ..it would probably be a 200 series alco ...but mpc era

 

It's probably a 8020.

 

The parallel plates/motor frames on these are vastly improved over the 200 series Alco / 600 series NW frames and motors of the post-1954 postwar era, are assembled much tighter and don't usually work loose at the stakings like the pre 1970 motors.

 

The problem you describe could be attributable to the oddball 1970-1971 only "scout type" hollow roller pickups. To truly assess the operation of the loco, you have to do it on the track with the rollers giving positive pressure on the wiper. For best performance, the rollers have to be cleaned well with an abrasive wheel on a Dremel, and the copper spring/wiper has to be cleaned with a good electrical contact cleaner. The plastic parts/halves only position the rollers and give a mounting/riveting point for the copper wiper, they are not part of the superstructure of the motor.

 

Even after all that cleaning, those rollers still do not work well. On the 8030 and 8031, leftover "Hillside" 2328-173 collector assemblies were added either at the factory or by dealers(as provided by MPC) to the non-powered trucks to improve performance.

 

For Alcos and switchers, the trucks are molded to accept the 1055-37 collector assemblies, but I've never seen these installed by MPC.

Bill, On occasion for these motor I have found too much slop on the brush housing.  When in reverse it would jam the armature as the motor reverse direction and thrusted in the opposite direction.

 

Loosen the top housing and adjust to center the armature.  Make sure smooth armature operation in both directions.  If too much vertical movement on the armature you can add a set screw.  Or add a nylon thrust washer on the shaft.  G

If this is the motor with no adjustable set screw on top, my experience is 9 times out of 10 adding a thrust washer, or two, will clear the problem. In reverse the armature shaft worm gear is 'climbing' the worm wheel an binding against the brush holder.

 

The other option is to swap out the brush holder with one that has the set screw.

 

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