Heating, Ventilation, and Air Conditioning (HVAC ) Electrical Practice Test

What component may be used to start a motor by providing an initial surge of current?

1. A switch

2. A relay

3. A capacitor

4. A fuse

The correct answer is: A capacitor

The correct choice is a capacitor because it can be used to provide an initial surge of electrical current to start an electric motor. This surge, often referred to as a "starting current" or "starting boost," helps the motor overcome inertia and begin turning. Capacitors store electrical energy and release it quickly, which is especially beneficial in starting applications, allowing for a stronger initial torque. In HVAC systems, capacitors are commonly used with single-phase induction motors, such as those found in air conditioning units and heat pumps. The capacitor creates a phase shift in the current, which produces a rotating magnetic field that helps start the motor more efficiently. The other components mentioned have different roles: switches control the flow of electricity but do not provide additional current; relays can manage circuits and control devices but don't specifically provide a starting surge; and fuses protect electrical circuits from overloads by breaking the circuit when current exceeds a certain level, but do not assist in starting motors.