Which components are typically part of a basic three-position start-stop control circuit?

Which components are typically part of a basic three-position start-stop control circuit?

• A. Start pushbutton, Stop pushbutton, Overload relay, Contactor
• B. Start pushbutton, Stop pushbutton, Interlock, Contactor
• C. Pushbutton, Fuse, Contactor, Relay
• D. Reset switch, Start button, Run relay, Contactor

Answer: (A)

A basic start-stop motor control relies on four pieces working together: a Start pushbutton, a Stop pushbutton, an overload device, and a contactor. The Start pushbutton is normally open, so pressing it completes the control circuit and energizes the contactor coil. Once the coil is energized, the contactor closes its main power contacts to start the motor, and its auxiliary contact can provide a holding path to keep the coil energized even after you release the Start button. The Stop pushbutton is normally closed and serves to interrupt the coil circuit when pressed, which releases the contactor and stops the motor. The overload relay sits in the coil/motor circuit to protect the motor; if current goes too high, it trips and opens the circuit, stopping the motor to prevent damage. This combination gives a simple, reliable start-stop action with protection and a self-holding run state. Other options include components like interlocks, fuses, or reset/run devices that may appear in other starter configurations, but they aren’t essential to the basic three-position start-stop setup.

A basic start-stop motor control relies on four pieces working together: a Start pushbutton, a Stop pushbutton, an overload device, and a contactor. The Start pushbutton is normally open, so pressing it completes the control circuit and energizes the contactor coil. Once the coil is energized, the contactor closes its main power contacts to start the motor, and its auxiliary contact can provide a holding path to keep the coil energized even after you release the Start button. The Stop pushbutton is normally closed and serves to interrupt the coil circuit when pressed, which releases the contactor and stops the motor. The overload relay sits in the coil/motor circuit to protect the motor; if current goes too high, it trips and opens the circuit, stopping the motor to prevent damage. This combination gives a simple, reliable start-stop action with protection and a self-holding run state.

Other options include components like interlocks, fuses, or reset/run devices that may appear in other starter configurations, but they aren’t essential to the basic three-position start-stop setup.