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Messages - DSE

#1
Large / One Truck Trolley Motor Brushes and Springs
January 09, 2013, 03:04:25 AM
I like to get several sets of motor brushes and brush tension springs for the one truck electric Trolley motor.  A set of brush holders would also be nice to get in case of loss or damage to the ones I have.

I ran my Santa Claus Trolley for a couple of weeks at low speeds pulling a couple of coaches 3 to 4 hours a day.  It then started to not be able to run at full speed, required a push to get going sometimes and then got much worse with a track voltage meter showing the full on Bachmann throttle voltage normally 16 volts being pulled down to below 10 volts and the Trolley running at very slow speeds.  This normally indicates worn brushes that have worn too short for the tension springs to make good electrical connection with them against commutator contacts. 

I checked the motor and found it has snap in brush holders where the electrical connection are on the motor.  These brush holders pry out with the flat blade of a small jewelers screw driver.  I've also pulled them out with the tip of a blunt needle nose pliers.  The spring tension is caped with a folded over copper rounded tab.  I was able to first remove the spring by opening up the folded over tab, but there was no brush connected to it.  I then pried out the brush holder and pushed out what was left of the brush with the shaft of jewelers screw driver.  One brush measured 0.15" long a little over an 1/8".  There was also a lot of black dust that washed out from the motor from a spraying of WD40.  Both brush tension springs managed to get away.  The black dust may have been brush debris that was causing some mild shorting explaining the big voltage drops I was seeing.  Several  people in the Garden Railroad forum say with a similar Bachmann Trolley they only went one week before the motor burned out.  With a more robust power supply that didn't drop voltage under this mild dust shorting a lot more heat might develop causing the motor to melt and burn. 

These brushes seem to only be good for about 25 to 40 hours of run time and the heavy dusting causes electrical problems.  This may be a compromise for better electrical conduction and commutator wear, but harder long wearing brushes that don't dust so much would seem advantages.  That said my Z-guage Marklin F-units are only related at 25 hours run time for their brushes and they are a lot more difficult to change.