Motor Speed Calculator — Formula
## AC Induction Motor Speed
The speed of an induction motor depends on the supply frequency, number of poles, and load-dependent slip.
### Formulas
**N_sync = 120 f / P** (synchronous speed)
**N_actual = N_sync (1 - s)** (actual speed)
where f is the supply frequency in Hz, P is the number of poles, and s is the slip (as a decimal). Synchronous speed is the rotating magnetic field speed. The rotor always turns slightly slower.
The speed of an induction motor depends on the supply frequency, number of poles, and load-dependent slip.
### Formulas
**N_sync = 120 f / P** (synchronous speed)
**N_actual = N_sync (1 - s)** (actual speed)
where f is the supply frequency in Hz, P is the number of poles, and s is the slip (as a decimal). Synchronous speed is the rotating magnetic field speed. The rotor always turns slightly slower.
Exemplo Resolvido
A 4-pole motor on 50 Hz supply with 3% slip at full load.
- Synchronous speed = 120 x 50 / 4 = 1500 RPM
- Actual speed = 1500 x (1 - 0.03) = 1455 RPM