Industrial Engineer · phase 9 of 16
Motor Nameplate Speed
Rated loaded shaft speed used to estimate slip and improve motor-control accuracy.
The Explain card
- Plain English
- The nameplate speed is how fast the loaded motor actually turns at rated frequency, a little below synchronous speed. The gap is the slip, and the drive uses it to estimate load and compensate.
- Example
- A four pole motor has a synchronous speed of 1800 rpm and a plate that reads 1750. Enter 1750 and the drive knows this motor slips about 50 rpm at full load.
- Why it matters
- A drive told 1800 thinks the motor has no slip and runs vector control on a wrong model, which shows up as poor low speed torque and hunting. Autotune can measure some of this, and the plate is still the place to start.
- Hook
- The plate says what the shaft really does.
Where it sits in the deck
Phase 9: VFD Ratings, Sizing, and Motor Data
Nameplate arithmetic, where the currents, voltages and duty ratings decide whether a drive can actually run the motor you bolted it to.
