Electrical Machines Two transformers with identical rating, are designed with flux densities of 1.2 and 1.4 Wb / m2 respectively. The weight of first transformer per kVA is none of these. equal to that of second transformer. more than that of second transformer. less than that of second transformer. none of these. equal to that of second transformer. more than that of second transformer. less than that of second transformer. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current Cannot be predicted due to insufficient data. Would be equal to If1. Would be equal to If1/2. Woud be equal to 2If1. Cannot be predicted due to insufficient data. Would be equal to If1. Would be equal to If1/2. Woud be equal to 2If1. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An alternator is feeding an infinite busbar. Its prime mover is suddenly shutdown. The alternator will start working as induction motor. come to stand still. continue to work as alternator but the direction of rotation will reverse. continue to work as synchronous motor with same direction of rotation. start working as induction motor. come to stand still. continue to work as alternator but the direction of rotation will reverse. continue to work as synchronous motor with same direction of rotation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines As compared to DOL starting, a cage induction motor with star-delta starting shall have more starting time. reduced starting current. more starting torque. smoother acceleration. more starting time. reduced starting current. more starting torque. smoother acceleration. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The introduction of interpoles in between the main poles improves the performance of a dc machine, because the inequality of air-gap flux on the top and bottom halves of the armature is removed the flux waveform is improved with reduction in harmonics a counter-emf is induced in the coil undergoing commutation the interpoles produce additional flux to augment the developed torque the inequality of air-gap flux on the top and bottom halves of the armature is removed the flux waveform is improved with reduction in harmonics a counter-emf is induced in the coil undergoing commutation the interpoles produce additional flux to augment the developed torque ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To achieve spark less commutation brushes of DC generator are rocked ahead so as to bring them None of these just behind the magnetic neutral axis. just ahead of magnetic neutral axis. in magnetic neutral axis. None of these just behind the magnetic neutral axis. just ahead of magnetic neutral axis. in magnetic neutral axis. ANSWER DOWNLOAD EXAMIANS APP
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