Distribution factor or winding factor

The factor by which there is a reduction in the emf due to distribution of coils is called distribution factor (Kd).

The distribution factor is defined as the ratio of resultant emf when coils are distributed to the resultant emf when coils are concentrated.

It is also known as winding factor or breadth factor.

Kd = sin(mβ/2) / msin(β/2)