Journeyman Electrician Practice Exam

What is a characteristic of a Design C AC motor?

1. High starting torque

2. Medium starting torque

3. Low starting torque

4. Variable starting torque

The correct answer is: Medium starting torque

A Design C AC motor is characterized by medium starting torque, which is essential for various applications that require a balance between the capability to start under load and the overall efficiency of the motor during normal operation. This design provides adequate torque to initiate motion without excessive inrush current that could lead to overheating or damage to the motor. In such motors, the torque is optimized to provide satisfactory performance in applications where the load does not require high initial torque to overcome inertia. This makes Design C motors well-suited for tasks where the load is consistent and manageable right from the start. The medium starting torque is a compromise that allows these motors to perform well in a variety of scenarios while minimizing energy consumption when compared to high-torque designs. This characteristic is particularly valuable because it supports a range of industrial and commercial applications. Understanding the specific torque characteristics allows electricians and engineers to select the appropriate motor type for the intended application, ensuring efficiency and reliability in operation.