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Motor Speed Calculator

Calculate AC induction motor synchronous and actual running speeds

🔌 Phase 3 Calculator

Inputs

Standard: 50 Hz (AU/NZ) or 60 Hz (US)

Typical: 2–5%

>Optional parameters

Results

Synchronous Speed

1500

rpm

Actual Motor Speed

1455

rpm

Frequency50 Hz
Number of Poles4
Motor Typeinduction
Slip3%

Speed Difference: 45 rpm due to slip

Important: These results are indicative only and must be verified by a qualified electrical engineer or the motor manufacturer before use in design or installation.

Motor Speed Guide

AC induction motor speed is determined by the supply frequency and the number of poles. The synchronous speed represents the theoretical speed of the rotating magnetic field, while the actual motor speed is lower due to slip.

Key Concepts

  • Synchronous Speed (Ns): Speed of the rotating magnetic field, determined by frequency and pole count.
  • Slip: The difference between synchronous and actual motor speed, expressed as a percentage.
  • Actual Speed: The real operating speed of the motor rotor under load, always less than synchronous speed.
  • Poles: The number of magnetic poles on the motor stator. Even-numbered values from 2 to 12.

Standard Frequencies

50 Hz: Used in Australia and most countries outside North America.
60 Hz: Used in North America and some other regions.

Motor Types

Different motor types have different slip characteristics. Typical slip values range from 2% to 5% for standard industrial motors, with higher slip in high-torque designs and lower slip in premium-efficiency motors.

Disclaimer: This calculator is provided as a guide only and must be verified by a qualified electrical engineer before use in design or installation.