Electrical Machines A self-excited shunt generator fails to build up, because 1. the field circuit is open 2. The armature circuit is open 3. the residual magnetism is absent 4. The direction of rotation is wrong From these, the correct answer is 1, 2 and 3 1, 3 1, 2, 3 and 4 3 only 1, 2 and 3 1, 3 1, 2, 3 and 4 3 only ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In shunt dc motor the direction of rotation of the motor will reversed. When only armature terminals are reversed. either field terminals are reversed or armature terminals are reversed. only field terminals are changed. none of above. only armature terminals are reversed. either field terminals are reversed or armature terminals are reversed. only field terminals are changed. none of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a loaded DC motor, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will improve and the speed rises. improve and the speed falls. deteriorate and the speed rises. deteriorate and the speed falls. improve and the speed rises. improve and the speed falls. deteriorate and the speed rises. deteriorate and the speed falls. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Slip test is performed to determine All of these positive sequence reactance and negative sequence reactance direct axis reactance and quadrature axis reactance slip All of these positive sequence reactance and negative sequence reactance direct axis reactance and quadrature axis reactance slip ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In an induction motor, what is the ratio of rotor input to rotor copper loss? 1-S 1/S S 1/(1-S) 1-S 1/S S 1/(1-S) ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The mechanical power is developed by a DC motor is maximum when back emf is equal to applied voltage. none of above. back emf is equal to half of applied voltage. back emf is equal to twice of applied voltage. back emf is equal to applied voltage. none of above. back emf is equal to half of applied voltage. back emf is equal to twice of applied voltage. ANSWER DOWNLOAD EXAMIANS APP
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