Moto Maintenance Tips - Motor Maintenance
Today, we would like to discuss motor maintenance.
Most permanent magnet DC-powered electric motors use brushes to transmit power from the source (battery) to the commutator. The power then continues to the rotor that is wound with conductive wire, producing a strong magnetic field that will repel the magnet facing it on the inside of the motor case. This is what makes the rotational torque that will power your vehicle.
One of the disadvantages of using a brushed DC motor is that eventually the brushes will wear down and need to be replaced, similar to how brake pads wear on disc brakes. In most cases, the brushes will last a VERY long time in a properly maintained DC electric motor. Things that can cause excessive and pre-mature wear include running the motor too fast, applying more power (voltage or amperage) than the motor is specified for, excessive load on the motor, and harsh motor conditions like sand, water, or dust around the motor. But if the motor is occasionally inspected and cleaned with compressed air, the motor brushes in your vehicle will last for thousands of miles.
To inspect, first remove the battery cables from the battery bank. Lift the rear of the vehicle (after blocking the wheels). Remove the gold-colored band on the rear of the motor (it has a latch and removes easily). Pull back on the spring covering the brush and pull brush from the motor. It will still 
be attached by heavy wire. Inspect the brush for cracks and excessive wear.
After removing all four brushes, blow out the motor with compressed air, and then inspect the commutator. It should be smooth all around and quite shiny.
If brushes need to be replaced, simply remove bolt holding each brush wire; remove and replace.
Next you will have to clean up the commutator. It usually looks black and nasty when the brushes are removed. Use a piece of 280 grit sandpaper and hold it in place while a friend spins the motor with a wrench or power drill. Work your way up to at least 400 grit sandpaper, continuing until the commutator looks shiny. Then you can break in the motor.
1. Make sure there is no load on the motor (disconnect the transmission or differential.)
2. Run the motor at about ¼ to 1/3 throttle for 20 minutes, being sure it is in the direction of usual motor operation.
3. Look through the rear vent and inspect for excessive arcing while running
4. Run the motor at 2/3 to ¾ throttle for about 10 minutes to an hou
5. Repeat Step 3.
6. Re-connect drive train and carefully drive vehicle for the first couple charge cycles.
Hopefully, this helps in any motor repairs you may have to fix either now or in the future. It is much easier than you might expect -- it just takes some time.
Happy Electric Motoring!
