Electrical Machines Minimum allowable resistivity of power transformer insulating oil is generally taken as 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 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 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 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 In a dc generator operating on load with its brushes on the geometrical neutral axis (GNA), the magnetic neutral axis (MNA) is shifted in the direction of rotation. Now, if the brushes are given a lead of 90° (electrical), then the MNA will shift forward by 90° shift forward by more than 90° coincide with the GNA shift forward by less than 90° shift forward by 90° shift forward by more than 90° coincide with the GNA shift forward by less than 90° ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Copper brushes in DC machine are used where low voltage and high currents are involved. None of these where high voltage and low current. in both of above cases. where low voltage and high currents are involved. None of these where high voltage and low current. in both of above cases. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Series generators are used in which of the following applications? All of these Air crafts. Used as boosters in dc distribution or transmission. Arc welding. All of these Air crafts. Used as boosters in dc distribution or transmission. Arc welding. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Resistance commutation is used generally in case of fractional kW DC machines. DC machines bellow 5 kW. None of these DC machines above 10 kW. fractional kW DC machines. DC machines bellow 5 kW. None of these DC machines above 10 kW. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which is the arrangement of windings in a core type single phase transformer? Lv on one core limb and hv on the other Sandwiched lv and hv discs on each core limb Half lv inside and half hv outside on each core limb Half hv inside and half lv outside on each core limb Lv on one core limb and hv on the other Sandwiched lv and hv discs on each core limb Half lv inside and half hv outside on each core limb Half hv inside and half lv outside on each core limb ANSWER DOWNLOAD EXAMIANS APP
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