In the above equations s1 is the number of slots, 2p is the number of poles and m1 is the number of phases. Putting γ = π/(m1q1) into eqn (A.2) the distribution factor for a 60◦ phase belt has the following well known form

kd1 = sin[π/(2m1)]

q1 sin[π/(2m1q1)] (A.6)

Including the stator slot skew and the effect of slot openings, the total winding factor for the fundamental space harmonic ν = 1 is

kw1 = kd1kp1ksk1ko1 (A.7)

where the skew factor

ksk1 = sin[πbsk/(2τ)] πbsk/(2τ)

= sin[πpbsk/(s1t1)] πpbsk/(s1t1)


and slot opening factor

ko1 = sin [πρb14/(2t1)]

πρb14/(2t1) (A.9)

In eqns (A.8) and (A.9) bsk is the stator slot skew, b14 is the stator slot opening (Fig. A.2) and ρ is given by eqn (5.107). The stator slot opening factor is very small and in typical machines can be neglected, e.g., for b14/(2t1) = 0.1 and ρ = 1 the slot opening factor ko1 = 0.9995.