The angle between rotating stator flux and rotor poles is called
Right Answer is:
Torque angle
SOLUTION
Effect of load on Synchronous motor
When the mechanical load on a D.C. motor or an A.C. motor is increased, the speed decreases This, is turn, decreases the back or counter e.m.f. (Eb) so that the source is able to supply more current to meet the increased load demands. However, this action cannot take place in the synchronous because the rotor must run at the synchronous speed at all loads.
Fig. (a) shows the relative position of a stator and rotor pole at no load, poles centers are directly inline with each other. Fig. (b ) represents the relative position of the stator and the rotor poles after a mechanical load has been added to the motor. Now there has been a shift of the rotor pole in a direction opposite to that of the stator field flux and the direction of the rotor. It may be kept in mind that there has been no change in speed as the rotor will continue to rotate at synchronous speed. There is only an angular displacement between the centers of the stator and rotor field poles. The angular displacement shown is called the Torque angle.
