7.4.2

To calculate the synchronous speed of an induction motor in revolutions per minute, use the formula Srpm = 120 x F/P, where Srpm is the synchronous speed, 120 is a constant, F is the supply frequency in cycles per second, and P is the number of motor winding poles. For example, for a 4-pole motor connected to a 60 Hz power supply, the calculation is Srpm = 120 x 60/4 = 1800 rpm.