Which component is used to switch the dryer motor from start to run?

Which component is used to switch the dryer motor from start to run?

• A. Limit switch
• B. Centrifugal switch
• C. Pressure switch
• D. Solenoid

Answer: (B)

The motor uses a starting winding to get up to speed, and a centrifugal switch is the device that disconnects that starting winding once the motor reaches enough speed. When the dryer is starting from rest, the switch is closed, allowing current to flow through the start winding (and any associated capacitor) to produce the necessary starting torque. As the rotor speeds up, centrifugal force opens the switch, removing the start winding from the circuit and leaving only the run winding to keep the motor running. This automatic transition prevents the starting winding from overheating and keeps the motor running smoothly. The other components listed serve different safety or control roles: a limit switch stops the dryer if it overheats, a pressure switch monitors vent pressure, and a solenoid controls other functions but not the start-to-run transition of the motor.

The motor uses a starting winding to get up to speed, and a centrifugal switch is the device that disconnects that starting winding once the motor reaches enough speed. When the dryer is starting from rest, the switch is closed, allowing current to flow through the start winding (and any associated capacitor) to produce the necessary starting torque. As the rotor speeds up, centrifugal force opens the switch, removing the start winding from the circuit and leaving only the run winding to keep the motor running. This automatic transition prevents the starting winding from overheating and keeps the motor running smoothly. The other components listed serve different safety or control roles: a limit switch stops the dryer if it overheats, a pressure switch monitors vent pressure, and a solenoid controls other functions but not the start-to-run transition of the motor.