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 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 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 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 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following is/are the advantages of carbon brush over the copper brush? All of these In case of any sparking they will be less damaged than copper brushes They are self lubricating in nature They are not hard as copper brush All of these In case of any sparking they will be less damaged than copper brushes They are self lubricating in nature They are not hard as copper brush ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the highest possible speed of turbo alternators? 3000 rpm 1500 rpm 4000 rpm 1000 rpm 3000 rpm 1500 rpm 4000 rpm 1000 rpm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 500 V, 55 kVA single phase alternator has an effective resistance of 0.5 Ω. An excitation current of 10 A produces 200 A armature current on short circuit and an emf of 450 V on per circuit. The synchronous reactance will be 25.564 Ω. 2.781 Ω. 2.74 Ω. 2.241 Ω. 25.564 Ω. 2.781 Ω. 2.74 Ω. 2.241 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In one 132 / 33 kV transformer the LV resistance is 0.02 per unit. The resistance referred to HV side is 0.08 pu. 0.16 pu. 0.02 pu. 0.01 pu. 0.08 pu. 0.16 pu. 0.02 pu. 0.01 pu. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which type of motors are preferred in lifts? DC series motors. DC compound motors. None of these DC shunt motors. DC series motors. DC compound motors. None of these DC shunt motors. ANSWER DOWNLOAD EXAMIANS APP
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