ABSTRACT
A three-phase supply is generated when three coils are placed 120◦ apart and the whole rotated in a uniform magnetic field as shown in Fig. 20.2(a). The result is three independent supplies of equal voltages which are each displaced by 120◦ from each other as shown in Fig. 20.2(b). (i) The convention adopted to identify each of the
phase voltages is: R-red, Y-yellow, and B-blue, as
(ii) The phase-sequence is given by the sequence in which the conductors pass the point initially taken by the red conductor. The national standard phase sequence is R,Y, B.
