Ns = 120·f / P - fundamental relationship between line frequency, pole count and a synchronous/induction motor’s magnetic-field speed.
Formula
$$ N_s = \frac{120 \cdot f}{P} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $f$ | Line frequency | Hz | grid |
| $P$ | Number of magnetic poles | - | motor nameplate |
| $N_s$ | Synchronous (field) speed | rpm | result |
Sources
- IEC 60034-1 - Rotating electrical machines.