Most electric motors used in household appliances such as vacuum cleaners, washing machines, power tools and more, have an armature with a commutator on top. As the armature spins around the driveshaft, a carbon brush on each side of the motor makes contact with the armature. Eventually, these brushes can wear down, causing the motor to fail. If you can access the top of the motor, you can check your motor brushes and change them if needed.
Disconnect the appliance's power cord from the electrical socket.
Remove any housing or electrical panel to gain access to the top of the electrical motor in your appliance.
Locate the two brush housings. They should look like a long, rectangular tube on opposite sides near the top of the motor, pointing toward the centre. Inspect one of the brush housings. There should be a screw or a clip on the end of the housing that, once removed, will allow the spring-loaded brush to be removed.
Remove the spring or clip, and pull out the spring-loaded brush. Notice exactly how the brush comes out of the housing, as it will need to be put back in precisely the same position. If you replace the brushes, the new ones will need to be installed in the same manner that the old ones are removed.
Inspect the inner carbon tip of the brush at the end of the spring. If it looks pitted or worn, it probably needs to be replaced with new brushes from the manufacturer of the motor.
Slip the old brush (or the new one if the old brush is worn) back into the brush housing exactly as it was removed, and tighten the screw or clip to hold the brush into the housing.
Remove, inspect and return or replace the brush on the opposite side of the motor. Then, replace the housing or panel that you removed to access the brush. Plug in the power cord, and test the unit.
One sign that brushes may be wearing out is if you see some sparks in the motor near the top of the armature.
Do not attempt to change brushes in an electric motor without first disconnecting the motor from power.