Motor Frequency Calculator

Calculate the operating frequency of AC induction motors

Motor Frequency Calculator

Compliant with NEMA and IEC Standards

Results:

Frequency (Hz): 0.00

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How to Use the Calculator

Input Motor Data

  1. Enter the "Number of Poles" of the motor.
  2. Input the "Motor Speed (RPM)" (Revolutions Per Minute).

Calculate Frequency

  1. Click the "Calculate" button.
  2. The result will display the motor's operating frequency in Hertz (Hz).

Reset and Re-calculate

  1. Click the "Reset" button to clear all fields.
  2. Enter new values to perform another calculation.

Motor Frequency Fundamentals

Synchronous Speed

Synchronous speed is the speed of the rotating magnetic field in an AC motor. It's determined by the frequency of the power supply and the number of poles in the motor.

  • Higher frequency means higher synchronous speed.
  • More poles mean lower synchronous speed.

Slip

  • In induction motors, the rotor always runs slightly slower than the synchronous speed. This difference is called "slip".
  • Slip is necessary to induce current in the rotor windings.
  • The actual motor speed is synchronous speed minus slip.

Key Formulas:

Synchronous Speed (RPM) = (120 × Frequency) / Number of Poles

Frequency (Hz) = (Motor Speed (RPM) × Number of Poles) / 120

Calculation Formulas

Motor Frequency (Hz):
Frequency = (RPM × Poles) / 120

Example Calculation

Consider a 4-pole motor running at 1750 RPM:

Number of Poles: 4

Motor Speed (RPM): 1750

Frequency = (1750 × 4) / 120

Frequency = 7000 / 120

Frequency ≈ 58.33 Hz

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