An electrical generator is an electrical device that converts mechanical energy (or power) into electrical energy (or power). The working principle of dc generator is based on dynamically induced emf. According to the Faraday’s law of electromagnetic induction whenever a conductor cuts by the magnetic flux or field, dynamically induced e.m.f. produced in it.
Φ = flux per pole in Weber (Wb)
Z = total number of armature conductors
N = speed of armature in r.p.m.
P = number of poles
A = number of parallel paths in armature winding
Eg = generated emf in volts
Flux cut by one conductor in one revolution dΦ = PΦ Wb
Time taken to complete one revolution, dt = 60/N
The number of conductors conducted in series in each parallel path = Z/A
Average induced e.m.f. across each parallel path or across armature terminals,
For Wave Winding
Number of parallel paths, A = 2
For Lap Winding
Number of parallel paths, A = Number of poles
Thus, we conclude that the induced e.m.f. is directly proportional flux per pole (Φ) and speed (N).