In a three-position start-stop control circuit, which component directly energizes the motor controller when the start button is pressed?

In a three-position start-stop control circuit, which component directly energizes the motor controller when the start button is pressed?

• A. Contactor
• B. Overload relay
• C. Pushbutton
• D. Circuit breaker

Answer: (A)

In this type of circuit, a contactor is the device that actually switches the motor’s power. The start button provides a control signal, energizing the coil of the contactor. Once the coil is energized, the contactor’s main contacts close and deliver current to the motor controller, turning the motor on. The stop button opens the coil circuit to de-energize the contactor, stopping the motor. The overload relay is there for protection in the circuit, and the circuit breaker is a protective device that interrupts power; neither directly energizes the motor. So the component that directly energizes the motor controller when the start button is pressed is the contactor.

In this type of circuit, a contactor is the device that actually switches the motor’s power. The start button provides a control signal, energizing the coil of the contactor. Once the coil is energized, the contactor’s main contacts close and deliver current to the motor controller, turning the motor on. The stop button opens the coil circuit to de-energize the contactor, stopping the motor. The overload relay is there for protection in the circuit, and the circuit breaker is a protective device that interrupts power; neither directly energizes the motor. So the component that directly energizes the motor controller when the start button is pressed is the contactor.