E.M.F. Equation of a D.C. Generator

E.M.F Equation of DC Generator

As the armature rotates and cuts the magnetic lines of force, a voltage is generated in its coils. The e.m.f. induces in the conductors according to ‘Faraday’s Law of Electromagnetic Induction’. The value of induced e.m.f. depends upon the lengths of the conductor, the magnetic field strength, and the speed at which the coil rotates. In the case of a generator, the emf of rotation is called the Generated emf or Armature emf and is denoted as Eg.

Let Φ= flux/pole in Wb
Z = total number of armature conductors
P = number of poles
A = number of parallel paths = 2 for wave winding
A= P for lap winding
N = speed of armature in r.p.m.
Eg = e.m.f. of the generator

Thus, it is clear that the induced emf is directly proportional to the speed and flux per pole.