Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 2, 3 ,5 1, 2, 3 2, 3, 4 2, 3, 4, 5 2, 3 ,5 1, 2, 3 2, 3, 4 2, 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop synchronous motor torque. induction motor torque. induction generator torque. DC motor torque. synchronous motor torque. induction motor torque. induction generator torque. DC motor torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Oil is provided in an oil filled transformer for cooling. both cooling and insulation. lubrication. insulating. cooling. both cooling and insulation. lubrication. insulating. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3-phase induction motor, if the supply voltage and frequency are reduced by the same ratio, then slip at which maximum torque occurs is more and maximum torque remains constant more and maximum torque decreases less and maximum torque decreases less and maximum torque increases more and maximum torque remains constant more and maximum torque decreases less and maximum torque decreases less and maximum torque increases ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When applied rated voltage per phase is reduce to one half, the starting torque of three phase squirrel cage induction motor becomes 1/4 of the intial value twice the initial value 1/2 of the initial value 4 time the initial value 1/4 of the intial value twice the initial value 1/2 of the initial value 4 time the initial value ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The efficiency of a transformer is mainly dependent on core losses. copper losses. dielectric losses. stray losses. core losses. copper losses. dielectric losses. stray losses. ANSWER DOWNLOAD EXAMIANS APP
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