Capacitor

HVAC capacitors store electricity in order to provide more torque for starting the blower motor and to help ease the usage of single-phase alternating current supplied by electric utilities. There are two types of HVAC capacitors—start and run—with both releasing their electrical charges to allow the current to flow at maximum levels by ensuring that voltage and current are optimally synced. Single-phase alternating current only creates one magnetic field, which does not provide enough power to turn the rotor and initiate the motor’s start. The start capacitor creates the needed second magnetic field which causes the alternating current to rise, fall, and reverse itself to create enough torque to start turning the rotor. A switch disengages the starting capacitor once the motor reaches operational speed. Another switch engages the run capacitor, which creates another magnetic field, which helps the blower motor operate with less required current than would be needed without the capacitor. Absent the run capacitor, blower motors would need to be much larger and require far more electricity.