# Induction Motor Calculator

Calculate the synchronous speed, slip and rated torque for an induction motor

**Tip:** registered users can save calculations.

## Symbols

- f - system frequency (Hz)
- n
_{r}- rated (or rotor) speed (rpm) - n
_{s}- synchronous speed (rpm) - P - number of poles
- P
_{r}- motor rated power (kW) - S - motor slip (%)
- T
_{r}- rated torque (Nm)

## Formulae

Synchronous Speed

${n}_{s}=\frac{120f}{P}$

Rotor Slip

$S=\frac{{n}_{s}-{n}_{r}}{{n}_{s}}\times 100\%$

**Note**: for locked rotor nr = 0, therefore S = 1. The slip will decrease as the rotor speed increases.

Rated Torque

${T}_{r}=\frac{9550-{P}_{r}}{{n}_{r}}$