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. 0.649. 0.573. 0.512. 0.443. 0.649. 0.573. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, 1. reactance voltage is proportional to armature current 2.reactance voltage is proportional to core length 3.reactance voltage is due to self-flux of the coil undergoing commutation 4. armature-cross flux is neutralized by interpolar flux 5. interpolarmmf is more than armature mmf in the interpolar zone From these, the correct answer is 1, 2, 3, 4 1, 2, 5 1, 3, 5 2, 3, 4 1, 2, 3, 4 1, 2, 5 1, 3, 5 2, 3, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Eb/V ratio of a DC motor is an indication of Running Torque. Speed regulation. Starting torque. Effiency. Running Torque. Speed regulation. Starting torque. Effiency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following voltage regulator is preferred for providing large values of load current? None of these Zener diode shunt regulator. Transistor shunt regulator. Transistor series regulator. None of these Zener diode shunt regulator. Transistor shunt regulator. Transistor series regulator. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In speed control of DC Series motor, speed lower than the rated speed can be obtained by Any of the above. Connecting an additional resistance in the field circuit. Connecting an additional resistance in stator circuit. Connecting an additional resistance in the armature circuit. Any of the above. Connecting an additional resistance in the field circuit. Connecting an additional resistance in stator circuit. Connecting an additional resistance in the armature circuit. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the mechanical power is developed by a DC motor maximum None of above. Back emf is equal. back emf is equal to applied voltage. Back emf is equal to half of applied voltage. None of above. Back emf is equal. back emf is equal to applied voltage. Back emf is equal to half of applied voltage. ANSWER DOWNLOAD EXAMIANS APP
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