Solution:

Given data:
Number of slots (S) = 36
Number of poles (P) = 4
Conductors per slot (C) = 2

A simplex lap winding means that each coil spans over one slot only.

Back pitch (yB):
The back pitch is the distance between the two sides of a coil on the back of the armature, measured in terms of armature slots.

For a simplex lap winding, the back pitch is equal to the number of coils per pole (Q) multiplied by the number of slots per pole (S/P), i.e.

yB = Q × S/P

By formula, Q = C × P/2 (since each coil spans over one slot only and there are P/2 coils per pole)

∴ yB = C × S/2

∴ yB = 2 × 36/2 = 36

Therefore, the back pitch is 36 slots.

Front pitch (yF):
The front pitch is the distance between the two sides of a coil on the front of the armature, measured in terms of armature slots.

For a simplex lap winding, the front pitch is given by the expression:

yF = yB ± 1

where the positive or negative sign is used depending on whether the winding is right-handed or left-handed.

In this case, the winding is not specified as right-handed or left-handed, so we can choose either.

Let's choose a right-handed winding, which means we take the positive sign:

∴ yF = yB + 1

∴ yF = 36 + 1 = 37

Therefore, the front pitch is 37 slots.

Conclusion:
In summary, the back pitch of the simplex lap winding is 36 slots and the front pitch is 37 slots, assuming a right-handed winding.

P=4, S= 36
As we know, Number of slots = number of coils(C) = 36
Therefore,
Back pitch(Yb) = {(2 × C)/P} + 1 = 19
Front pitch(Yf) = {(2 × C)/P} -1 = 17