What is the purpose of holding contacts in a motor control circuit?

• A. To energize the stop button
• B. To allow continuous operation after starting
• C. To prevent electrostatic discharge
• D. To limit current flow

Answer: (B)

The purpose of holding contacts in a motor control circuit is to allow continuous operation after starting. When a motor is started, a momentary push of the start button energizes the coil of the relay or contactor, which closes the contacts and starts the motor. The holding contacts, which are also part of the circuit, are designed to keep the coil energized even after the start button is released. This is accomplished by creating a parallel path for current to flow through the holding contacts, maintaining the relay in its energized state.

This functionality is essential because it enables the motor to continue running without needing to keep the start button pressed, thereby allowing for consistent operation until a stop command is given. The ability to maintain this state not only simplifies operation but also enhances safety, as it ensures that the motor can run independently without continuous manual input.