When to Replace Motor Brushes?
My router motor has begun to sound a bit fuzzy when it runs. What does that mean?
John Tetreault, Durham, CT
It means you need to replace the motor’s brushes. When the brushes on a universal motor become worn, they no longer touch the commutator firmly, forcing electrical current to jump, or “arc,” between them. Arcing is that fuzzy or scratchy noise you’re hearing. You should be able to see that arcing through the motor housing vents. Look for flashes of light.
Unplug the router and remove the brushes. Check their condition against the owner’s manual to determine if they need to be replaced. Always replace both brushes and make sure they can slide easily in the holder so that the springs can hold them against the commutator as they wear.