Question

What is the EMF generated per path in a simplex wave-wound DC generator?
1. \( \frac{{\phi ZN}}{{60P}} V\)
2. \( \frac{{\phi ZNP}}{{60}} V\)
3. \( \frac{{\phi ZN}}{{120P}} V\)
4. \( \frac{{\phi ZNP}}{{120}} V\)

Answer 1

Correct Answer - Option 4 : \( \frac{{\phi ZNP}}{{120}} V\)

Concept:

EMF equation of a DC Generator:

As the armature rotates, a voltage is generated in its coils, which is called Generated EMF or Armature EMF, and is denoted by Eg.

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

Where,

Eg = Generated EMF

P = Number of poles of the machine

ϕ = flux per pole in weber

Z = total number of armature conductors

N = speed of armature in revolution per minute (r.p.m)

A = number of parallel paths in the armature winding

Also,

A = P ⋅ m

Where,

m = multiplexity (simplex/duplex)

In wave winding, multiplexity is always 2 (two)

Therefore, A = 2

While in lap winding, there are two types:

1. Simplex Lap winding: m = 1

          ∴ A = P

2. Duplex Lap winding: m = 2 

         ∴ A = 2P

NOTE:

If multiplexity is not mentioned, then always take simplex lap winding i.e. m = 1

Application:

EMF generated per path in a simplex wave-wound DC generator

∴ A = 2, m = 1

∴ \(E_g = \frac{{\phi ZNP}}{{120}} V\)