A capacitor is an electrical component that stores electrical charge and provides the initial torque needed to start motors and improve operating efficiency in HVAC systems. Run capacitors in PSC blower motors are rated between 5 and 20 microfarads (MFD) at 370 to 440 volts and operate continuously during system operation. Start capacitors provide momentary high-voltage pulses that create initial motor rotation before the motor reaches running speed.
Types and Applications
Run capacitors are cylindrical components commonly mounted directly to motor housings or nearby mounting brackets. Start capacitors are typically larger and mounted separately with automatic switches that disconnect them after motor startup. Dual capacitors combine both run and start functions in single housings for space-saving installation in compact equipment.
Maintenance and Replacement
Capacitor failure is common after 5 to 8 years of operation due to thermal stress and voltage fluctuations. Symptoms include slow motor starting, reduced airflow, or complete motor failure. Replacement capacitors must match original specifications within 5 to 10 percent of microfarad rating and voltage classification to prevent motor damage and safety hazards.