Electrical Machines If in a sub – station there is one 132 / 33 kV transformer whose secondary is connected with primary of one 33 / 11 kV transformer, the total transformation ratio of the sub – station will be, 12. 3. 7. 4. 12. 3. 7. 4. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The direction of generated emf in the armature coil of a DC machine is 1. the same as that of the current in a generator 2. the same as that of the current in a motor 3. opposite to that of the current in a generator 4. opposite to that of the current in a motor From these, the correct answer is 1, 4 1, 3 2, 3 2, 4 1, 4 1, 3 2, 3 2, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The field system of an alternator is usually excited 110 / 220 V AC. 250 / 250 V DC. 3 - Φ, 50 Hz and 400 V. 230 V AC. 110 / 220 V AC. 250 / 250 V DC. 3 - Φ, 50 Hz and 400 V. 230 V AC. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An induction motor has a rotor resistance of 0.002 Ω / phase. If the resistance is increased to 0.004 Ω / phase then the maximum torque will reduced to half remain unaltered increase by 200% increase by 100% reduced to half remain unaltered increase by 200% increase by 100% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In travelling cranes for hoisting and lowering which type of motor is preferred? AC slip ring motor. DC series motor. Synchronous motor. Single phase induction motor. AC slip ring motor. DC series motor. Synchronous motor. Single phase induction motor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction in DC generators will result in increase in slip. open circuit. reduction in generated emf. short circuit. increase in slip. open circuit. reduction in generated emf. short circuit. ANSWER DOWNLOAD EXAMIANS APP
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