The pitch factor is the ratio of emf of the short-pitch coil to the full-pitched coil.

The pitch factor is defined as the ratio of the voltage induced in a short-pitched coil to the voltage induced in a full-pitched coil, when both coils are subjected to the same flux distribution.

Mathematically, the pitch factor can be expressed as:

Pitch factor = (sin(πm/N))/(πm/N)

where

m is the number of slots by which the coil is short-pitched
N is the total number of stator slots,

• The pitch factor is always less than 1, and it decreases as the coil span becomes shorter.
• The pitch factor is used in the design and analysis of AC machines to predict the voltage induced in the stator windings under different operating conditions.