Red Seal Industrial Electrician Practice Exam

Which of the following describes AC motors?

1. They require direct current to operate

2. They are used primarily in battery-operated devices

3. They run on alternating current

4. They have a fixed torque regardless of speed

The correct answer is: They run on alternating current

AC motors are designed to operate using alternating current, which is the primary characteristic that defines them. This type of current alternates its direction periodically, allowing AC motors to convert electrical energy into mechanical energy more efficiently than some other motor types. The alternating current enables the motor's electromagnetic fields to generate rotation within the motor, which is essential for driving mechanical loads in various applications. The other options do not accurately reflect the characteristics of AC motors. For example, AC motors do not require direct current to operate; instead, they specifically need alternating current. They are also not typically used primarily in battery-operated devices, as those devices often rely on DC motors for their design. Lastly, AC motors do not have a fixed torque regardless of speed; their torque can vary with the operating speed depending on the motor type and application specifics. By understanding these key characteristics, one can better appreciate the functionality and applications of AC motors in industry and everyday use.