Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the field winding connection must be reversed the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding must be replaced the field winding connection must be reversed the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding must be replaced ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Transformer cooling and insulating oil must be of low resistivity. high viscosity. low BDV. low viscosity. low resistivity. high viscosity. low BDV. low viscosity. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt motor has external resistance Ra and Rf in the armature and field circuits respectively. Armature current at starting can be reduced by keeping Ra maximum and Rf maximum Ra maximum and Rf minimum Rf maximum and Ra minimum Ra minimum and Rf minimum Ra maximum and Rf maximum Ra maximum and Rf minimum Rf maximum and Ra minimum Ra minimum and Rf minimum ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The main disadvantage(s) of the ward-Leonard system is/are high initial cost. poor overall efficiency. all of above. high maintenance cost. high initial cost. poor overall efficiency. all of above. high maintenance cost. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following transformer insulating oil generally used in India? Naphtha based insulating oil. Olefin based insulating oil. Aromatics based insulating oil. Paraffin based insulating oil. Naphtha based insulating oil. Olefin based insulating oil. Aromatics based insulating oil. Paraffin based insulating oil. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 400 V, 50 Hz, 30 Hp, three phase IM is drawing 50 A current at 0.8 p.f lagging. The stator and rotor copper losses are 1.5 KW and 900 W respectively. The friction and windage losses are 1050 W and core losses are 1200 W. The air gap power of the motor will be 25 kW. 24.11 kW. 23.06 kW. 26.21 kW. 25 kW. 24.11 kW. 23.06 kW. 26.21 kW. ANSWER DOWNLOAD EXAMIANS APP
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