Electrical Machines Saving of copper in auto transformer is increased as compared to two winding transformer, when transformation ratio K approaches to zero. unity. infinity. two. zero. unity. infinity. two. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Transformer cooling and insulating oil must be of low resistivity. low viscosity. low BDV. high viscosity. low resistivity. low viscosity. low BDV. high viscosity. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Compensating windings are used in DC generators None of these mainly to reduce the eddy currents by providing local short circuit. to provide path for the circulation of cooling air. to neutralize the cross magnetizing effect of the armature reaction. None of these mainly to reduce the eddy currents by providing local short circuit. to provide path for the circulation of cooling air. to neutralize the cross magnetizing effect of the armature reaction. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous machine, if φ is the flux per pole and f is the frequency of the emf induced E then E ∝ f/φ E ∝ 1/(φf) E ∝ φf E ∝ φ/f E ∝ f/φ E ∝ 1/(φf) E ∝ φf E ∝ φ/f ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous motor when the rotor speed exceeds the synchronous speed during hunting negative sequence currents are generated. the damper bars develop induction motor torque. the damper bars develop induction generator torque. the damper bars develop synchronous motor torque. negative sequence currents are generated. the damper bars develop induction motor torque. the damper bars develop induction generator torque. the damper bars develop synchronous motor torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 V DC machine has an armature resistance 1 Ω. If the full load current is 20 A, the difference of induced voltage between generator and motor is 20 V. 60 V. 40 V. 0 V. 20 V. 60 V. 40 V. 0 V. ANSWER DOWNLOAD EXAMIANS APP
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