Quick Connect Capacitor

In single phase electric motors, the run winding is not capable of starting the motor. To start the motor, a secondary start winding uses a starting capacitor to introduce a rotating electric. This rotating field is not constant, but is sufficient to start the motor spinning. When the motor reaches operating speed, the capacitor shifts to the run winding to control the speed of the motor.

A faulty run capacitor often becomes swollen, with the sides or ends bowed or bulged out. When this happens the motor will ‘buzz’ but not start.

Causes of start capacitor failure
The most common causes of capacitor failure in single phase pumps are severe voltage irregularities (voltage drop or surge) from the power supply or from overheating in a pump with a blocked impeller or seized rotor.
Over long periods of use, the capacitance of the capacitor deteriorates. As a result the motor may fail to start or run at full power.