Electrical Machines What is the necessity of copper brushes in a dc motors? To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. None of these. To convert alternating supply current to direct current. To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. None of these. To convert alternating supply current to direct current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC generator in case the brushes are moved so as to bring them in magnetic neutral axis, then, there will be none of above. cross-magnetization as well as demagnetization. cross-magnetisation. demagnetisation. none of above. cross-magnetization as well as demagnetization. cross-magnetisation. demagnetisation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 8 pole, 50 Hz single phase induction motor is running at 690 rpm. Its slip with respect to forward field is -1.92 -0.08 0.08 1.92 -1.92 -0.08 0.08 1.92 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which of the following speed control of DC motor the speed obtained is below than the rated speed? Any of above. Armature voltage control. Field resistance control. Armature circuit resistance control. Any of above. Armature voltage control. Field resistance control. Armature circuit resistance control. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In speed control of DC Series motor, speed lower than the rated speed can be obtained by Connecting an additional resistance in stator circuit. Connecting an additional resistance in the field circuit. Any of the above. Connecting an additional resistance in the armature circuit. Connecting an additional resistance in stator circuit. Connecting an additional resistance in the field circuit. Any of the above. Connecting an additional resistance in the armature circuit. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A large series motor is never started without some mechanical on it because otherwise it will Draw too much current. Open fuse or circuit breaker. Produce sparking at brushes. Develop excessive speed and damage itself. Draw too much current. Open fuse or circuit breaker. Produce sparking at brushes. Develop excessive speed and damage itself. ANSWER DOWNLOAD EXAMIANS APP
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