Saturday, November 8, 2014

AC Generator frequency as a function of RPM


w - angular velocity.
f - frequency (number of cycles per second, expressed in Hz).
P - number of poles (= N + S poles. ).
P/2 - number of pole pairs. Above generator example has two poles and one pole pair.
Ns - number of revolutions per second 
Nm - number of revolutions per minute
Nm=60*Ns.

w=2Pi*f = (P/2) * N * 2Pi * 1/sec

f=(P/2)*N/sec
f=(P/2)*Ns

f=(P/2)*Nm/60=P*N/120

f=P*Nm/120