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. 0.512. 0.443. 0.573. 0.649. 0.512. 0.443. 0.573. 0.649. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What will happen if the the supply terminals are reversed in case of a DC shunt motor? The motor will stop. The motor will run much faster in the same direction. The motor will run at its normal speed in the same direction as before. The motor will run in reverse direction. The motor will stop. The motor will run much faster in the same direction. The motor will run at its normal speed in the same direction as before. The motor will run in reverse direction. 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 winding was wrongly connected there was a break in the armature circuit field system lost residual magnetism field resistance was higher than critical resistance field winding was wrongly connected there was a break in the armature circuit field system lost residual magnetism field resistance was higher than critical resistance 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. Woud be equal to 2If1. Would be equal to If1. Would be equal to If1/2. Cannot be predicted due to insufficient data. Woud be equal to 2If1. Would be equal to If1. Would be equal to If1/2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction of an unsaturated DC machine is none of above. demagnetising. crossmagnetising. magnetising. none of above. demagnetising. crossmagnetising. magnetising. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the full load speed of 3-phase, 50Hz induction motor is 950 rpm, what is its half load speed nearly equals to? 950 rpm 975 rpm 1000 rpm 940 rpm 950 rpm 975 rpm 1000 rpm 940 rpm ANSWER DOWNLOAD EXAMIANS APP
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