E.M.F. Equation of a Generator

E.M.F. EQUATION OF A GENERATOR

Let

P = number of poles,

ϕ = flux/pole, webers (Wb),

Z = total number of armature conductors,

= number of slots × number of conductors / slot,

N = rotational speed of armature, r.p.m,

A = number of parallel paths in armature and

E = generated e.m.f. per parallel path in armature.

Average emf generated per conductor = dϕ/dt volt

Now, flux cut per conductor in one revolution, dϕ = Pϕ Wb.

Number of revolutions / second = N/60

⸫ Time for one revolution, dt = 60/N seconds

Hence, according to Faraday's laws of electromagnetic induction,

E.m.F. generated per conductor = PϕN/60 volts

For a lap wound generator:

Number of parallel paths, A = P

Number of conductor (in series) in one path = Z/P

⸫ E.m.f generator per path =

For a wave wound generator :

Number of parallel paths, A = P

Number of conductor (in series) in one path = Z/2

⸫ E.m.f generator per path =

In general, generated e.m.f

where

A = P ... for lap winding

= 2 ... for wave winding.