Differential leakage of a fractional slot winding

WHEN the conditions for balance are satisfied, a fractional-slot lap winding can be laid out in many different patterns, all of which are balanced. The usual pattern is that for maximum distribution factor of the main wave. If this pattern is called the “basic,” all other patterns can be derived from this one by cyclic shifts of coils from one phase to the other within the same repeatable group. The distribution factor of the main wave of the derived patterns, that is, of the patterns with cyclic shift of coils, is always smaller than that of the basic layout. As regards the distribution factors of the harmonics of the derived patterns, some are smaller and some larger than those of the basic pattern.