What Is Causing the Motor on an Electric Fan to Slow Down and Stop?

What Is Causing the Motor on an Electric Fan to Slow Down and Stop?

 

The torque to drive the motor of your electric fan comes from the magnetic field induced in the motor coils when electricity passes through the coils. When the fan slows down and stops, it could simply be because the coils are worn out, but it's often a burned-out capacitor.

 

The Run Capacitor

The capacitor on an electric fan is called a run capacitor, as opposed to a start capacitor that gives the needed extra torque for some motors to start. The run capacitor stores charge and delays the current momentarily, which gives the fan rotor time to turn and orient itself so that the induced magnetic force is effective. When the capacitor burns out, the electric current through the coil is too steady to generate torque, and the fan slows down and stops.

 

Replacing the Capacitor

The capacitor in a fan is often similar in shape to a resistor -- cylindrical with a wire at each end -- but it's a solid color. You'll usually find it soldered to the coil, although you may have to remove some protective packing to find it. After unplugging the fan, cutting out the bad capacitor, and soldering in a new one with the same capacitance, your fan should resume normal operation.