156 ELECTRICAL APPARATUS

(four with quarter-phase, Q, six with six-phase, S, three with
three-phase, T);

any fractional pitch winding then consists of the superposition
of two layers :

From co =
and

from co = 0to co = -~ — ~r->

2

and the integral (14) become:

F0an =

IT . PTT

.

A + T rq~ -2

\ cos ncodco + I cos noodu

. /7T , pir\ , . XT
smn - + ^r)+ sinnl --
\ 2 / \

4F . /7T

--
\q 2

SF . nir pmr , ^^

= — sin — cos ~-> (15)

HT q 2 ^ '

as for: n = l;an = 1, it is, substituted in (15):

8.F FQ _

TT . TT PTT;

sm - cos ~-
q 2

hence, substituting (16) into (15) :

. nir pmr

sin — cos ~-

. 7T 7)7T

sin - cos ~
q 2

For full-pitch winding:

p = 0.
It is, from (17):

. rnr
sin —

a." =

sin -
ff