Which description best defines a motor starter?

Which description best defines a motor starter?

• A. A device that directly powers the motor from the supply
• B. A motor control device that uses a small push button to activate a control relay and send electrical current to the motor
• C. A passive switch with no relay
• D. A device that measures motor temperature

Answer: (B)

Motor starters are control devices that let you start and stop a high-current motor using a low-current control circuit. They use a relay (contactor) to handle the motor’s current, plus often overload protection. The operator presses a small push button to energize the relay coil; when energized, the relay’s contacts close and power is sent from the supply to the motor, starting it. Releasing the button or triggering a stop circuit opens the control, de-energizes the coil, and the motor stops. This is why describing a device that uses a small push button to activate a control relay and send current to the motor best captures what a motor starter does. Other descriptions miss the essential control-relay mechanism or the protection role and thus don’t define a motor starter.

Motor starters are control devices that let you start and stop a high-current motor using a low-current control circuit. They use a relay (contactor) to handle the motor’s current, plus often overload protection. The operator presses a small push button to energize the relay coil; when energized, the relay’s contacts close and power is sent from the supply to the motor, starting it. Releasing the button or triggering a stop circuit opens the control, de-energizes the coil, and the motor stops. This is why describing a device that uses a small push button to activate a control relay and send current to the motor best captures what a motor starter does. Other descriptions miss the essential control-relay mechanism or the protection role and thus don’t define a motor starter.