Electrical Engineering ⇒ Topic : Frequency and speed

Frequency and speed. Consider a coil rotating at a speed of N r.p.m. in the field of P poles.As the coil moves past successive north and south poles, one complete cycle is generated. Obviously,in one revolution of the coil, P/2 cycles will be generated.

Now,                             Frequency, f = No. of cycles/sec

                                                          = (No. of cycles/revolution) x (No. of revolutions/sec)

For example, an a.c. generator having 10 poles and running at 600 r.p.m. will generate alternating voltage and current whose frequency is :