What are the signs of bad brushes on motor ?

[mauistardog]

What clues might indicated bad or worn brushes on an electrical motor ? I was told that my motor brushes are worn and that is why the cart goes real slow. The person never pulled the motor. The pedometer (sp ?) and controller was changed and the solenoid was tested by the original owner. I found the batteries to be bad...so bought a new set. Still no change in speed.
any help would be great before I pull the motor.

aloha
joe

[69makinitmine]

This is just like troubleshooting why the starter in your car won't crank the engine (like when it just drags). First thing I'd do is check all your cable ends for battery acid corrosion leeching up into the crimped on wire lug. Sometimes you can't see it and just have to change them. Then when you are sure the cables and all connections are good, try using a battery inductive type ammeter to see how many amps motor is drawing. It's called an "amp clamp" and some multimeters have it as an accessory. If amps are below motor rating I'd say it's the motor not passing the current. It's probably a combination of the brushes AND a worn/gummy commutator on armature. Have armature turned on lathe to "square" back up. When the brushes wear down the spring that pushes on them unwind and have less tension...and sometimes BOTTOM OUT to where they put NO pressire on brush!!! Also don't use TOO much grease in end bearing or it will leech back out onto clean commutator (if there is no grease slinger installed). Then a new set of brushes and maybe springs! Hope this helps!!!