Gas Fitter Practice Test

What device is used to verify that a dryer motor is running?

1. Motor safety switch

2. Motor sensor switch

3. High limit switch

4. Centrifugal switch

The correct answer is: Centrifugal switch

A centrifugal switch is the correct choice for verifying that a dryer motor is running due to its function in electric motors, particularly in appliances like dryers. This switch is typically engaged at startup and is designed to disconnect or reconnect certain electrical circuits based on the motor's rotational speed. When the dryer motor starts and reaches its designated speed, the centrifugal switch operates; this signaling ensures that the motor is running properly. If the motor fails to reach that speed, the centrifugal switch will not engage, which can trigger system safeguards to prevent overheating or electrical faults. Other devices mentioned serve different purposes. A motor safety switch mainly functions to protect against overloads or short circuits. The motor sensor switch is usually associated with detecting specific operational conditions but does not specifically verify motor running status. The high limit switch is related to temperature regulation and safety, preventing overheating by shutting down the dryer if temperatures exceed a preset limit.