Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Electrical Induction Motors - Synchronous Speed

Operating speed of an induction motor depends on the input power frequency and the number of magnetic poles in the motor.

Sponsored Links

The synchronous speed for an electric induction motor is determined by

  • the power supply frequency, and
  • the number of poles in the motor winding. 

The synchronous speed can be calculated as:

n = f (2 / p) 60                      (1)

where

n = shaft rotation speed (rev/min, rpm)

f = frequency of electrical power supply (Hz, cycles/sec, 1/s)

p = number of poles

Note - an induction motor will never reach its synchronous speed. If it did - the rotor would appear to be stationary to the rotating stator field since it would rotate with the same speed. With no relative motion between stator and rotor field no voltage will be induced in the motor. The speed of an induction motor is therefore limited to a speed below synchronous speed and the difference between synchronous speed and actual speed is called slip.

Example - Synchronous Speed of Electric Motor with Two Poles

A motor with two poles is supplied with power with frequency 50 Hz (1/s). The rotation speed can be calculated as

n =  (50 1/s) (2 / 2) (60 s/min) 

   = 3000 rpm (1/min)

Synchronous rotation speed at different frequencies and number of poles

Shaft rotation speed - n - (rev/min, rpm)
Frequency
- f -
(Hz)
Number of poles - p -
24681012
10 600 300 200 150 120 100
20 1200 600 400 300 240 200
30 1800 900 600 450 360 300
40 2400 1200 800 600 480 400
501) 3000 1500 1000 750 600 500
602) 3600 1800 1200 900 720 600
70 4200 2100 1400 1050 840 700
80 4800 2400 1600 1200 960 800
90 5400 2700 1800 1350 1080 900
100 6000 3000 2000 1500 1200 1000
  1. Motors designed for 50 Hz are most common outside U.S
  2. Motors designed for 60 Hz are most common in U.S

Variable Frequency Drive

A variable frequency drive modulates the speed of an electrical motor by changing the frequency of the power supply.

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Share

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Topics

Unit Converters

Temperature

oC
oF


Load Calculator!

Length

m
km
in
ft
yards
miles
naut miles


Load Calculator!

Area

m2
km2
in2
ft2
miles2
acres


Load Calculator!

Volume

m3
liters
in3
ft3
us gal


Load Calculator!

Weight

kgf
N
lbf


Load Calculator!

Velocity

m/s
km/h
ft/min
ft/s
mph
knots


Load Calculator!

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O


Load Calculator!

Flow

m3/s
m3/h
US gpm
cfm


Load Calculator!

3 10

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more