Section 14.3: The Synchronous Speed
The stator’s field is given by: F(q,t) = Fa + Fb + Fc = 1.5Fmsin(wt - pq)
The peak (max.) value of F(q,t) is 1.5Fm
This peak corresponds to wt - pq = p/2
The time-derivative of wt = pq - p/2 is w = p(dq/dt)
But dq/dt = w/p is the speed of rotation …
Which can be expressed as ns = 120f/p (in RPM) (see text p. 536)