Electrical Machines If the excitation is critical, the power factor of the alternator is None of these unity power factor. lagging power factor. leading power factor. None of these unity power factor. lagging power factor. leading power factor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt generator, when commissioned after a major repair of the field system, failed to build Up voltage. It was because field system lost residual magnetism field winding was wrongly connected field resistance was higher than critical resistance there was a break in the armature circuit field system lost residual magnetism field winding was wrongly connected field resistance was higher than critical resistance there was a break in the armature circuit ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed of a DC series motor is Inversely proportional to the armature current. Proportional to the armature current. Proportional to field current. Proportional to the square of the armature current. Inversely proportional to the armature current. Proportional to the armature current. Proportional to field current. Proportional to the square of the armature current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 2, 3, 4, 5 2, 3 ,5 2, 3, 4 1, 2, 3 2, 3, 4, 5 2, 3 ,5 2, 3, 4 1, 2, 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A compound dc generator is delivering full load current at a terminal voltage of 230 V. Its series-field winding gets short circuited. If its terminal voltage 1. becomes more than 230 V, it is overcompounded generator 2. becomes more than 230 V, it is differentially compounded generator 3. becomes less than 230 V, it is overcompounded generator 4. becomes less than 230 V, it is differentially compounded generator 5. becomes less than 230 V, it is level compounded generator From these, the correct answer is 1, 4, 5 2,3 2, 3, 5 1, 4 1, 4, 5 2,3 2, 3, 5 1, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For satisfactory performance of 3-phase 480V, 60 Hz induction motor, the supply voltage at 50 Hz should be equal to 420 V. 400 V. 480 V. 350 V. 420 V. 400 V. 480 V. 350 V. ANSWER DOWNLOAD EXAMIANS APP
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