Which motor requires an inverter to operate?

• A. AC traction motor
• B. DC traction motor
• C. Inverter
• D. Battery system

Answer: (A)

AC traction motors need an inverter because they require AC power with a controllable frequency to vary speed and torque. If the system’s power source is DC, an inverter converts that DC into AC and adjusts the frequency to control how fast the motor spins. DC traction motors can run directly from a DC supply, so they don’t need an inverter for basic operation. A battery system is just the power source, not a type of motor. So the motor that requires an inverter to operate is the AC traction motor.