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 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 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 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Larger values of air flux density is taken while designing IM for none. larger output. larger bore diameter. both. none. larger output. larger bore diameter. both. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following DC Motor uses 4-point starter? DC series motor. DC shunt motor with armature resistance. DC shunt motor with field weaking control. DC compound motor. DC series motor. DC shunt motor with armature resistance. DC shunt motor with field weaking control. DC compound motor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the load current and the flux of a DC motor are held constant and voltage applied across its armature is increased by 5%, the speed of the motor will depend on other factors. remain unchanged. increase by 5 %. reduce by 5 %. depend on other factors. remain unchanged. increase by 5 %. reduce by 5 %. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the no-voltage release in a DC motor starter fails to operate on failure of supply, on resumption of supply the motor will not start automatically. develop very low starting torque. start automatically without trouble. get damaged. not start automatically. develop very low starting torque. start automatically without trouble. get damaged. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction in a DC machine is in direct opposition to the main poles. is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. makes an angle of 90° with the main pole axis. is in direct opposition to the main poles. is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. makes an angle of 90° with the main pole axis. ANSWER DOWNLOAD EXAMIANS APP
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