Electrical Machines A DC Shunt Motor having shunt field resistance of 250 Ω and armature resistance of 0.5 Ω is connected to 250 V supply and load current of 21 A. What is the back emf generated ? 240 V. 150 V. 210 V 230 V. 240 V. 150 V. 210 V 230 V. 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 minimum and Rf minimum 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 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The air gap between stator and the rotor of the 3 - φ induction motor is kept air gap does not matter. as small as possible. as wide as possible. depends on the material of stator and the rotor. air gap does not matter. as small as possible. as wide as possible. depends on the material of stator and the rotor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 ,V 15 , kW 100 rpm shunt motor with armature resistance of 0.25 , W has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is 18.18% increase 36.36% increase 36.36% increase 36.36% decrease 18.18% increase 36.36% increase 36.36% increase 36.36% decrease ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the necessity of copper brushes in a dc motors? None of these. To increase the flux cutting by the rotor. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. None of these. To increase the flux cutting by the rotor. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following rotor requires damper winding? Cylindrical rotor. Both type rotor. None of these Salient pole rotor. Cylindrical rotor. Both type rotor. None of these Salient pole rotor. ANSWER DOWNLOAD EXAMIANS APP
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