Why is a bleed resistor necessary on a start capacitor?

A bleed resistor is essential on a start capacitor because it prevents the capacitor from discharging across relay contacts. When a start capacitor is used in a compressor system, it is designed to provide the extra torque needed to start the motor. Once the motor starts and reaches a certain speed, a relay typically disconnects the capacitor from the circuit to prevent it from affecting the normal operation of the compressor.

If a bleed resistor is not present, the stored energy in the capacitor could discharge through the relay contacts. This discharge can potentially damage the relay contacts and lead to improper operation of the compressor. The bleed resistor allows the capacitor to discharge gradually and safely, ensuring that the relay is not subjected to high transient voltages that could cause arcing or contact wear. By maintaining a controlled discharge path, the bleed resistor plays a critical role in the longevity and reliability of the compressor system.