Industrial Engineer · phase 11 of 16
Closed-Loop Control
Motor control that uses encoder or resolver feedback to regulate shaft speed, torque, or position.
The Explain card
- Plain English
- Closed loop means the drive measures the shaft with an encoder or resolver and corrects its output until the measurement matches the command. The feedback closes the loop.
- Example
- A winder must hold speed within a tenth of a percent as the roll builds. An encoder on the motor reports actual speed thousands of times a second and the drive trims its output to match.
- Why it matters
- Feedback buys accuracy, full torque at zero speed, and the ability to hold a load still, which is what hoists and positioning need. It also adds a cable, a device that can fail, and a fault the drive raises the moment the feedback disagrees with the model.
- Hook
- Measure, compare, correct, repeat.
Where it sits in the deck
Phase 11: VFD Control Modes and Tuning
How a drive decides what to send the motor, from plain volts per hertz up to closed loop vector control, and how each mode is tuned.
