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Figure 10.3 Stator windings connected in star: (a) two-pole winding; (b) four-pole winding
10.6 CONCEPT OF COIL SPAN, MECHANICAL, AND ELECTRICAL DEGREES
The angular distance between the two coil sides of a coil is called the coil
span. From Fig. 10.2 (a), it can be observed that the angular distance between
the two coil sides of coil R–R′ is 180°. The winding is for two poles. From
Fig. 10.2 (b) which has a four-pole winding, the angular distance between the
coil sides of coil R –R ′ is 90°. If we make a winding for eight poles, the coil
1
1
span will be reduced further to 45°. The change of coil span for windings of a
different number of poles has been further illustrated in Fig. 10.4.
