Formula for Synchronouse Speed

Motor synchronous speed determined by # of stator poles

RPM = 2F x 60
                 N

RPM= motor speed in revolutions per min

F= frequency in Hertz

60 = conversion from cycles per second to cycles per minute

N= number of poles in the motor

What would the speed be of a 4 pole motor operating on 220V 50Hz?


RPM = (2(50) x 60) / 4

RPM = 1500