Electrical Machines If a DC Series motor is connected across an AC supply it will burn. run at lower speed. not run. run at normal speed. burn. run at lower speed. not run. run at normal speed. 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 2, 4 ,5 1, 3, 5 2, 3 , 5 1, 4 2, 4 ,5 1, 3, 5 2, 3 , 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Minimum allowable resistivity of power transformer insulating oil is generally taken as 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The material used for commutator brushes is mostly carbon. cast iron. mica. copper. carbon. cast iron. mica. copper. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If in a sub – station there is one 132 / 33 kV transformer whose secondary is connected with primary of one 33 / 11 kV transformer, the total transformation ratio of the sub – station will be, 3. 12. 4. 7. 3. 12. 4. 7. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which of the following motors DC excitation is not required? 3-phase synchronous generator reluctance motor hysteresis motor 3-phase synchronous motor 3-phase synchronous generator reluctance motor hysteresis motor 3-phase synchronous motor ANSWER DOWNLOAD EXAMIANS APP
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