Question

For an identical DC generator, what should be the number of poles such that the emf generated in case of lap winding and wave winding configuration will be the same?
1. 8
2. 6
3. 2
4. 4

Answer 1

Correct Answer - Option 3 : 2

Concept:

Armature emf in a DC generator is given by,

\({E_g} = \frac{{\phi ZNP}}{{60A}}\)

ϕ is flux per pole

Z is the number of conductors

N is speed

P is poles

A is the number of parallel paths

For the lap winding, A = P

For the wave winding, A = 2

Calculation:

To have the same emf, the number of parallel paths must be same in both the cases.

Therefore, the number of parallel paths = A = P = 2

Number of poles = 2