How to Repair an Electric Motor

By James Stevens
Keep your motor running smoothly.

All electric motors contain copper windings on the armature, and magnets that are fixed to the outer casing. Electricity is passed to the windings in the armature via carbon brushes. The magnets repel the electrical energy and force the armature in the motor to rotate. You can service wiring connections, bearings and brushes yourself. If the problem persists or is more complex, you may need to have a professional to check it out.

Wiring Repair

Check the terminal wiring connections on the electric motor. Two wires connect to the terminals.

Disconnect the two wires from the terminals. Loosen the terminal screws using a screwdriver, then slide the wires out. Make a note of which wire connects to each terminal so you know how to replace them.

Cut off about ½ inch from the ends of the two wires using a knife, which will leave you with completely new wire to work on. Remove 1/4 inch of the plastic coating from the ends of the two wires using wire strippers. This leaves you with new copper wire, which allows you to make a good connection.

Brush the terminals using a wire brush to clean any dirt or grease. Replace the two wires under the terminal screws and tighten using a screwdriver. Ensure you connect the wires to the same terminals that you removed them from.

Turn on the power that supplies your motor to see if the repair has worked. If it does, the task is complete. If it doesn’t, follow the steps in Section 2.

Repair Brushes

Remove the carbon brush retainers on each side of the armature housing. Insert a suitably-sized screwdriver into the retainer and gently pry out the retaining clip. Be careful as you remove the brush retainers, as there are springs inside that may fall out.

Remove the springs. Pull them out using your fingers or a pair of pliers. Remove the old carbon brushes using long-nosed pliers. It they are difficult to get out, gently slide a small flat-head screwdriver between the brush and the armature so the brushes are released.

Slide new carbon brushes in the retainer slot, then put the springs in place. If you find they won’t go all the way in they need to be pushed into place. Use the flat side of a screwdriver to hold them, then push the retaining clip in place. Use your fingers or pliers to make sure the brushes and springs are secure.

Turn on your motor. If the brushes were the problem, your repair is complete. If not, follow the steps in Section 3.

Repair Bearings

Remove the screws that hold the two parts of the electric motor casing together using a screwdriver. Insert a flat-head screwdriver between the split in the casing to help release the top. Gently lift the top half off the bottom half to reveal the armature.

Lift the armature from the bottom part of the casing so you can access all the bearings. There are bearings in the front and back of both parts of the casing. Remove the old bearings by prying them out using a screwdriver and your fingers. Clean the area using a wire brush.

Put the new bearings into the bearing containers. Replace the armature, then place the top half of the motor casing onto the bottom half. Replace the screws, so the two halves are held tightly together. Rotate the armature using your fingers to help bed in the bearings.

Turn on the electric motor. If the bearings were the problem, your motor will operate and run quietly. If the motor doesn’t operate or operates noisily, then you need to get it checked out professionally.

About the Author

James Stevens has been writing articles for market research companies in the U.K. since 1990. He has written various country profiles for inclusion in comprehensive market reports including Vision One Research and Investzoom Market Research. Stevens holds a General Certificate of Education from Chelmsford College of Further Education.