Electrical Machines For satisfactory parallel operation of two transformers which of the following conditions is most essential, polarities of all transformers must be same. voltage ratio of all transformers must be same. percentage impedance of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. polarities of all transformers must be same. voltage ratio of all transformers must be same. percentage impedance of all transformers must be same. MVA rating of all transformer inversely proportional to impedance. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If residual magnetism of a shunt generator is destroyed accidentally it may be restored by connecting its shunt field to earth. to an AC source. in reverse. to a DC source. to earth. to an AC source. in reverse. to a DC source. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case the conditions for maximum power for DC motor are established, the efficiency of the motor will be Around 100 %. Less than 50 % Around 90 % Any where between 75 % and 90 %. Around 100 %. Less than 50 % Around 90 % Any where between 75 % and 90 %. 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 1/4 of the intial value 4 time the initial value 1/2 of the initial value twice the initial value 1/4 of the intial value 4 time the initial value 1/2 of the initial value twice the initial value ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Synchronous condensers are used to improve the power factor All of these improve starting torque reduce hunting improve the power factor All of these improve starting torque reduce hunting ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The sparking at the the brushes, in a DC machines is due to armature reaction. high resistance of carbon brushes. presence of commutator. reactance voltage. armature reaction. high resistance of carbon brushes. presence of commutator. reactance voltage. ANSWER DOWNLOAD EXAMIANS APP
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