When the rotor is rotating at a con

When the rotor is rotating at a constant speed, the flux-linkage of the armature winding is changing with time. Under the assumption of a sinusoidal flux distribution and constant rotor speed,the resulting coil voltage will be sinusoidal in time as shown in Fig. 14-2(b).The coil voltage passes through a complete cycle for each revolution of the two-pole machine of Fig. 14-1. Its frequency in cycles per second(Hz)is the same as the speed of the rotor in revolutions per second. The frequency of generated AC voltage is synchronized with the mechanical speed,and this is the reason the machine is called asynchronous machine.Thus a two-pole synchronous machine revolves at 3 000revolutions per minute(50 revolutions per second)to generate a 50 H2 AC voltage.