Electrical Machines On switching a DC motor to DC supply mains, it is found to rotate in the direction opposite to that for which it is designed. The DC motor is have an equal number of electrons and protons. Series shunt. Differentical compound. Cummulative compound. have an equal number of electrons and protons. Series shunt. Differentical compound. Cummulative compound. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding dc machines : 1. possible resistance of shunt-field winding is 1 Ω 2. possible resistance of series-field winding is 1 Ω 3. electrographite brushes are used for 230 V, 10 A machines 4. Copper-graphite brushes are used for 230 V, 10 A machines 5. Possible armature-circuit resistance is 1 Ω From these, the correct statements are 1, 4 1, 3, 5 2, 4 ,5 2, 3 , 5 1, 4 1, 3, 5 2, 4 ,5 2, 3 , 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The polarity of a DC generator can be reversed by any of above. increasing field current. reversing the field current. reversing field electric current as well as direction of rotation. any of above. increasing field current. reversing the field current. reversing field electric current as well as direction of rotation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A lap wound DC machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volts. The machine generates a voltage of 200 V. 100 V. 800 V. 400 V. 200 V. 100 V. 800 V. 400 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The fall in speed of the DC generator due to increase in load can be corrected by increasing the excitation. cooling the armature. increasing the input to the prime mover. reducing the load voltage. increasing the excitation. cooling the armature. increasing the input to the prime mover. reducing the load voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To achieve spark less commutation brushes of DC generator are rocked ahead so as to bring them in magnetic neutral axis. just behind the magnetic neutral axis. just ahead of magnetic neutral axis. None of these in magnetic neutral axis. just behind the magnetic neutral axis. just ahead of magnetic neutral axis. None of these ANSWER DOWNLOAD EXAMIANS APP
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