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 Dynamic braking can be used for compound motors. All of these series motors. shunt motors. compound motors. All of these series motors. shunt motors. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt generator, when driven without any excitation, showed an open circuit voltage of 12 V. When the field winding was excited, the voltage dropped to zero. It happened because there was no residual magnetism in the field circuit there was a break in the armature circuit field winding was wrongly connected field resistance was higher than critical resistance there was no residual magnetism in the field circuit there was a break in the armature circuit field winding was wrongly connected field resistance was higher than critical resistance ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the source voltage of a DC motor is increased, which of the following will decrease? Full load current. Starting torque, operating speed, full load current. Operating speed. Starting torque. Full load current. Starting torque, operating speed, full load current. Operating speed. Starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An induction motor has a rotor resistance of 0.002 Ω / phase. If the resistance is increased to 0.004 Ω / phase then the maximum torque will increase by 200% reduced to half remain unaltered increase by 100% increase by 200% reduced to half remain unaltered increase by 100% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If residual magnetism of a shunt generator is destroyed accidentally it may be restored by connecting its shunt field in reverse. to a DC source. to earth. to an AC source. in reverse. to a DC source. to earth. to an AC source. ANSWER DOWNLOAD EXAMIANS APP
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