Electrical Machines A commutator with a diameter of 50 cm rotating at 1000 rpm. For a brush width of 1.5 cm, find the time of commutation in ms. 0.649. 0.512. 0.443. 0.573. 0.649. 0.512. 0.443. 0.573. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In DC motors, under trailing pole tips, flux density will_______ ? either increase or decrease increase decrease None of these either increase or decrease increase decrease None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The wattage rating of a ceiling fan motor will be 200 - 250 W. 50 - 150 W. 10 - 20 W. 250 - 500 W. 200 - 250 W. 50 - 150 W. 10 - 20 W. 250 - 500 W. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A single phase transformer when supplied from 220 V, 50 Hz has eddy current loss of 50 W. If the transformer is connected voltage of 330 V, 75 Hz, the eddy current loss will be 168.75 W 112.5 W 75 W 50 W 168.75 W 112.5 W 75 W 50 W ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ω. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is 1.06 0.87 0.95 0.96 1.06 0.87 0.95 0.96 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines With the increase in speed of a DC motor back emf increases but line current falls. both back emf as well as line current increase. both back emf as well as line current fall. back emf falls and line current increases. back emf increases but line current falls. both back emf as well as line current increase. both back emf as well as line current fall. back emf falls and line current increases. ANSWER DOWNLOAD EXAMIANS APP
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