# 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)
• nr  - rated (or rotor) speed (rpm)
• ns  - synchronous speed (rpm)
• P   - number of poles
• Pr  - motor rated power (kW)
• S   - motor slip (%)
• Tr  - rated torque (Nm)

## Formulae

Synchronous Speed

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

Rotor Slip

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

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

Rated Torque

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

Cable Insulation Properties

Cable insulation is used to provide electrical separation between conductors of  a cable.  During the historical development of cables, numerous types...

Battery Sizing

This article gives an introduction to IEEE 485 method for the selection and calculation of battery capacity.

What is a rectifier transformer?

I've recently come across this question a couple times browsing the internet. Decided to give a quick answer here. A rectifier transformer is a transformer...

GE's Shingijutsu Factory

GE's latest thinking on product manufacturing is he Shingijutsu philosophy or Lean production system. They have started applying this at the Louisville...

Robotics - Home Innovations

We have a sister note to this (Robots - Interesting Video), in which I have posted some videos of interesting robots developed by commercial corporations...

Wiki Depreciation

We have had the Wiki with us for a long time now, but at last I have decided to say bye bye – more details on why below.

Variable Frequency Drive

Variable frequency drives are widely used to control the speed of ac motors.  This note looks at the mechanisms which enable drive units to control the...

Maximum Demand for Buildings

Estimating maximum demand is a topic frequently discussed. Working out how much power to allow for a building can be very subjective . Allowing too much...

Electrical Engineering

Electrical engineering is a field that covers a wide variety of sub-fields, including electricity and electronics. It is a field that goes back to the...

Meeting room of the future

The IET site has a video of a visit showing of a high tech meeting room developed at Napier University in Edinburgh. It a good demonstration of innovative...

Our website uses cookies so that we can provide a better experience.