Electrical Machines If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is Pi/Pc √(Pi/Pc) (Pi/Pc)2 Pc/Pi Pi/Pc √(Pi/Pc) (Pi/Pc)2 Pc/Pi ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an AC servomotor has one of its winding excited by AC, then voltage measured at the other winding with rotor running will be zero. constant independent of speed. proportional to square of rotor speed. proportional to rotor speed. zero. constant independent of speed. proportional to square of rotor speed. proportional to rotor speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 500 V, 55 kVA single phase alternator has an effective resistance of 0.5 Ω. An excitation current of 10 A produces 200 A armature current on short circuit and an emf of 450 V on per circuit. The synchronous reactance will be 2.781 Ω. 2.74 Ω. 25.564 Ω. 2.241 Ω. 2.781 Ω. 2.74 Ω. 25.564 Ω. 2.241 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Flashing the field of DC generator means creating residual magnetism by a DC source. neutralising residual magnetism. increasing flux density by adding extra turns of winding. making the magnetic losses forces parallel. creating residual magnetism by a DC source. neutralising residual magnetism. increasing flux density by adding extra turns of winding. making the magnetic losses forces parallel. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A part an alternator winding consist of eight coils in series, each having an emf of 20 V rms induced in it. Coils are placed in successive slots and between each slot and the next, there is an electrical phase displacement of 30°. Find the emf of eight coils in series 56.91 V. 66.91 V. 86.91 V. 76.91 V. 56.91 V. 66.91 V. 86.91 V. 76.91 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Current in a coil undergoing commutation is not able to get reversed completely by the end of commutation period. It is due to armature emf. coil resistance. None of these reactance voltage induced in the coil. armature emf. coil resistance. None of these reactance voltage induced in the coil. ANSWER DOWNLOAD EXAMIANS APP
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