Synchronous speed of a motor?

In a motor, synchronous speed is the speed at which the magnetic field rotates. Depending on motor design, the actual mechanical speed may be equivalent (synchronous motor) or slightly smaller (asynchronous motor).

The synchronous speed is a function of:

• The electrical frequency used, typically 60 Hz or 50 Hz.
• The number of poles the motor has.

The formula for calculating synchronous speed is:

• Sync. Speed (in RPM) = 120 x Frequency (Hz) / # poles