The synchronous speed of an induction motor is based on the supply frequency and the number of poles in the motor winding and can be expressed as:
ω = 2 · 60 · f / n (1)
where
ω = pump shaft rotational speed (rev/min, rpm)
f = frequency (Hz, cycles/sec)
n = number of poles
The rotational speed at different frequencies and number of poles can be listed as: