ABSTRACT
Examination of eqs. (3.19) and (3.35) shows that the maximum value of current in rotor t:>ar a lags the maximum value of the air-gap-density wave by the angle 82' which is the power factor angle of the blocked-rotor circuit. The air-gap flux-density wave rotates around the air gap at the angular velocity of w radians/second. Also, each rotor bar in the blocked rotor successively reaches its maximum value of current after the preceding one, and this rotor-bar current-wave effect rotates around the periphery of the rotor at the angular velocity of w radians/second. Then the phase displacement betwe~n the air-gap flux density and the rotor-b~r current is equal to the angle 82 for the blocked-rotor condition. Since 82 , the blockedrotor circuit power-factor angle, is always less than 90 degrees, there will always be a component of one of the two quantities in phase with the other quantity. Accordingly, a net unidirectional force will be exerted on each bar of the blocked rotor, causing the rotor to tend to rotate about the centerline of the shaft.
