I found two good looking Athearn motors in the scrap bin and immediately used them in two ailing Genesis 103s. To my surprise, they took off backwards down the test track. Now way back in the recesses of my memory, I seem to recall a discussion about a batch of Athearn motors that are wired backwards…anyone remember this.
I solved this application by reversing the trucks and marking the chassis to indicate this.
David Harriso, MSI and they’re in Washington
I have an old Bachmann F unit that is that way.
RMax
Dave,I don’t think the motors was wire backwards as much as the trucks was turn around…I had a SD9 that the trucks was put on backwards.In this case I removed the trucks and tested the motor…The motor was right but the trucks wasn’t. [:0] [8][B)]
Athearn motors have their contacts to the brushes 180 degrees apart. it’s easy to re-install them upside down.
Reversing the trucks solves this but puts a reverse electrical potential on the Chassis. Not a problem, if two different chassis don’t touch, or get connected by metal couplers that are NOT insulated from the chassis (KaDee #4’s for example).
The OTHER answer is to reverse the motor or it’s connections.
CURIOUS: How are the inside bronzed oil-lite wheel-bearing Athearn and Life Like engines doing on the MSI long distances?
Don Gibson
No problem with the Athearns bronze bearings…Life Like??? Hmm all we’re running are the SD60Ms and I think they have copper wheel wipers, but I’ll check for sure tomorrow.
David Harrison, the Kato’s are in WA!! Hurray!!
Doing maintenance last night on a bunch of Athearn’s and two of mine were backwards, but this could have been my doing from earlier dissassembly. Reverse the magnets and it will run correctly. In most Athearn’s, correct polarization is motor armature faces forward on the chassis, with the truck contacts “pointing” toward the conductor/fireman side of the locomotive. The left rail contacts the frame and the bottom of the motor, and the right rail contacts the top motor clip or wire and the top of the motor.
Now, on the SD40-2’s and maybe some others, it’s different, because there’s an extra gear in the truck, that would make the locomotive run the opposite direction if it was set up this way, so the motor is mounted in the opposite direction, with the armature facing rearward. This preserves the polarity of the motor, frame and trucks.