Which section of a DC drive is capable of controlling the motor direction?

• A. Control
• B. Power
• C. Feedback
• D. Input

Answer: (A)

Direction is determined by the control section. This part takes the operator’s forward or reverse command (and the speed reference) and, using the feedback from the motor, generates the control signal that specifies the required polarity and magnitude of voltage to the motor. In other words, the control loop decides which way the motor should spin and how fast, then communicates that to the power stage.

The power section simply carries out that command by switching devices to apply the appropriate voltage and polarity to the motor. The input section provides the user command, and the feedback section provides real-time motor data for the control loop to use, but neither decides the direction by itself.