Electrical Machines The sparking at the the brushes, in a DC machines is due to high resistance of carbon brushes. presence of commutator. armature reaction. reactance voltage. high resistance of carbon brushes. presence of commutator. armature reaction. reactance voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Commutator in DC generator is used for reduce losses collecting of current increase efficiency convert AC armature current in to DC reduce losses collecting of current increase efficiency convert AC armature current in to DC ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In the 3-phase induction motor, the resultant flux is of a constant nature and is 3 times maximum value of flux due to any phase 1/2 times maximum value of flux due to any phase 3/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase 3 times maximum value of flux due to any phase 1/2 times maximum value of flux due to any phase 3/2 times maximum value of flux due to any phase equal to φm, where φm is the maximum flux due to any phase ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The mechanical power is developed by a DC motor is maximum when 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. back emf is equal to applied voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an additional resistance is connected in series with a DC motor operating at rated speed, the speed of the motor will Increase. Remain unaltered. Reduce. Oscillate around the normal speed. Increase. Remain unaltered. Reduce. Oscillate around the normal speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If starting current of a 3 - Φ induction motor is 5 times the rated current, while rated slip is 4 %, then ratio of starting torque to full load torque is 0.8. 1. 0.6. 0.4. 0.8. 1. 0.6. 0.4. ANSWER DOWNLOAD EXAMIANS APP
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