Electrical Machines 1 KVA, 230 V, 50 Hz, single phase transformer has an eddy current loss of 30 watts. The eddy current loss when the transformer is excited by a dc source of same voltage will be zero watt 30 W less than 30 W more than 30 W zero watt 30 W less than 30 W more than 30 W ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 V, DC shunt motor is operating at a speed of 1440 rpm. The armature resistance is 1.0 Ω and armature current is 10 A. of the excitation of the machine is reduced by 10%, the extra resistance to be put in the armature circuit to maintain the same speed and torque will be 1.79 Ω 1.8 9 Ω 2 .1 Ω 3.1 Ω 1.79 Ω 1.8 9 Ω 2 .1 Ω 3.1 Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The output voltage of a DC generator is E = V + IaRa. E = V + Ia. E = V – IaRa. E = V + Ra. E = V + IaRa. E = V + Ia. E = V – IaRa. E = V + Ra. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt generator builds up to a voltage of 220 V at no load while running at its rated speed. If the speed of the generator is raised by 25% kepping the circuit conditions unaltered, then the Voltage to which the machine would build up will not change and remain at 220 V increase to value lying between 220 V and 1.25 times 220 V increase to 1.25 times 220 V increase to a value greater than 1.25 times 220 V not change and remain at 220 V increase to value lying between 220 V and 1.25 times 220 V increase to 1.25 times 220 V increase to a value greater than 1.25 times 220 V 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 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. Cannot be predicted due to insufficient data. Would be equal to If1. Would be equal to If1/2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In V/f speed control of 3-phase induction motor, with increase in frequency, the slip at which maximum torque occurs decrease. either of these. None of these increase. decrease. either of these. None of these increase. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS