Flux cut per second by each conductor = 2 φm f
Average emf generated in each conductor = 2 φm f Z
Average emf generated per phase = kd kc 2 φm f Z
r.m.s emf generated per phase = kf kd kc 2 φm f Z
For sinusoidal waveform when kf is 1.11 then emf generated
= 1.11 *2 kd kc φm f Z
= 2.22 kd kc φm f Z
kf →form factor
f → Frequency
φm → Flux maximum
Z → Turns per phase
kd → Breadth factor or distribution factor
kc → Coil span