Which section of a solid-state DC drive is capable of varying the motor speed above and below the motor base speed?

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

Answer: (A)

Varying motor speed around the base speed is controlled by the drive’s control logic. The control section decides how fast the motor should run and whether to change the armature voltage or weaken the field to reach speeds above the base speed, or strengthen the field or reduce voltage to go below it. It uses the speed feedback to adjust these commands in real time, then passes the appropriate signals to the power section, which actually delivers the commanded voltages to the motor. The feedback section only provides the speed measurement, and the input section handles user signals. So the control section is the part responsible for making speed changes above and below base.