on30 shay motor brush contact issue

[slugsmasher]

I have a non dcc shay that has been sitting around for a few years.  It was running fine in dc mode on my test track and was broke in it seemed.  I recently got a sound decoder and installed it.  Upon testing the loco on a dcc module, the sounds work but no motor running.

Reverted back to dc jumper and tested on dc test track and not running but light comes on.  Not drawing any amperage other than for light which was minimal at full throttle.

Disassembled loco down to motor and cylinders assembly.  Hooked up power direct to motor and could only get it to run if I gently pressed in the brush contacts.  I tried some contact cleaner and ran it for a while at full power.  At first it was intermittent and then smoothed out.  I still have to press  in one of the contacts to keep the motor running. 

So question is...do I just keep running it this way until it "breaks in" again?  or do I get a new motor? or just solder the brush pins to the motor leads so they don't move?

thanks for any replies

Rich B

[Stevelewis]

This  appears  to  be  a  Decoder  installation  problem  not  the  motor,  check  the  decoder  wiring  first

The fact  that  the  motor  would not run when  you tested it  on DC  when disassembled  could be  due to the  fact  that when assembled the   motor brushes have  some pressure  exerted on them by the parts surrounding it.

[slugsmasher]

Thanks for the reply.

I'm pretty sure the decoder install is good.  I put an NMRA connector on it so it is a simple matter to revert to DC operation by disconnecting the decoder and installing a jumper.  I am testing with the jumper installed and hooking up my power supply directly to the motor brush contacts.  The decoder is totally out of the picture in this configuration.

I am thinking either the brushes are glazed or the commutator on the motor is corroded.  Going to run it again tonight with power direct to motor to try to break it in some more.  I figured out how to clamp some tweezers on the motor brush pin to hold it against the commutator.

Rich B

[slugsmasher]

Update for anyone interested.  I fixed the motor by soldering the brush contacts to the brush rivet.  This probably isn't the best solution but it works.  Once it starts messing up again I'll just replace the motor.  Here are some photos that illustrate the issue:


Here is the only way I could get the motor to run.  The tweezers are clamping type and they are hooked up to a DC power pack with the alligator clips.


The gap in the little "L" bracket for the brush is noticeable here, it is sprung out a few thousandths.  Not sure how this happened since I have never taken this loco apart since new.


Low tech fix by gently applying some pressure to the "L" bracket and soldering in place.  Works great but we will see how long it lasts.

I suppose one positive note is that I now know how to break this loco down to parade rest and it still works afterwards.

Rich B