Electrical Machines The material used for commutator brushes is mostly carbon. cast iron. copper. mica. carbon. cast iron. copper. mica. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When applied rated voltage per phase is reduce to one half, the starting torque of three phase squirrel cage induction motor becomes 1/2 of the initial value twice the initial value 4 time the initial value 1/4 of the intial value 1/2 of the initial value twice the initial value 4 time the initial value 1/4 of the intial value ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The principal of starting of 3 - Φ IM is similar to transformer with short-circuited secondary. repulsion motor type starting. synchronous motor. capacitor run IM. transformer with short-circuited secondary. repulsion motor type starting. synchronous motor. capacitor run IM. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The synchronous speed of an induction motor will be increased by decreasing of frequency. increasing number of poles. speed can not be increased. increasing of frequency. decreasing of frequency. increasing number of poles. speed can not be increased. increasing of frequency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Under which of the following conditions hunting of synchronous motor is likely to occur ? Over-excitation. Periodic variation of load. Over-loading for long period. Small and constant load. Over-excitation. Periodic variation of load. Over-loading for long period. Small and constant load. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3 - Φ IM in order to eliminate cogging the number of stator slots must be unequal to number of rotor slots and skewed in shape. equal to number of rotor slots. an integral multiple of number of rotor slots. either (B) or (C). unequal to number of rotor slots and skewed in shape. equal to number of rotor slots. an integral multiple of number of rotor slots. either (B) or (C). ANSWER DOWNLOAD EXAMIANS APP
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