Help with frozen axle on MTH PCC Trolley

[DMUinCT]

danrunner

I bought a PCC car and the wheels connected to the motor (via a screw) won't budge.  The axle rotates when not connected so does the screw/drive mechanism.  Once I put these 2 back together--the wheels/unit is frozen.  Wheels won't turn a tad.

 Anyone have any ideas?

 Thanks

 Dan

What you describe is called a "Worm Gear Drive".   The motor turns the "Worm" (screw)(can be steel or nylon)  that spins the "Gear" (usually brass or nylon) .  This is considered one of the best forms of motor drive, both in models and industry.    In most cases, the Worm/Gear is considered "locking", you can not turn the wheels without power to the motor.    In most cases a "flywheel" is added to the motor shaft to smooth operation and provide momentum.  

The worm should be riding centered on the gear with a few thousands clearence (not bottomed out) and turning the motor should be free and easy.

[danrunner]

I bought a PCC car and the wheels connected to the motor (via a screw) won't budge.  The axle rotates when not connected so does the screw/drive mechanism.  Once I put these 2 back together--the wheels/unit is frozen.  Wheels won't turn a tad.

 

Anyone have any ideas?

 

Thanks

 

Dan