Induction Motor Parameters

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

Title/Description:

System Frequency:

Number of poles:

Rated Speed (rpm):

Rated Power (kW):

Synchronous Speed (rpm):

Slip (%):

Rated Torque (Nm):

Tip: registered users can save calculations.

Calculate

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

$«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«msub»«mi»n«/mi»«mi»s«/mi»«/msub»«mo»=«/mo»«mfrac»«mrow»«mn»120«/mn»«mo»$nbsp;«/mo»«mi»f«/mi»«/mrow»«mi»P«/mi»«/mfrac»«/math»$

Rotor Slip

$«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»S«/mi»«mo»-«/mo»«mfrac»«mrow»«msub»«mi»n«/mi»«mi»s«/mi»«/msub»«mo»-«/mo»«msub»«mi»n«/mi»«mi»r«/mi»«/msub»«/mrow»«msub»«mi»n«/mi»«mi»s«/mi»«/msub»«/mfrac»«mo»$#215;«/mo»«mn»100«/mn»«mo»%«/mo»«/math»$

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

Rated Torque

$«math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«msub»«mi»T«/mi»«mi»r«/mi»«/msub»«mo»=«/mo»«mfrac»«mrow»«mn»9550«/mn»«mo»$#215;«/mo»«msub»«mi»P«/mi»«mi»r«/mi»«/msub»«/mrow»«msub»«mi»n«/mi»«mi»r«/mi»«/msub»«/mfrac»«/math»$