Electrical Machine MCQs

16. Question

Consider a system consisting of a synchronous generator working at a lagging power factor, a synchronous motor working at an overexcited condition and a directly grid-connected induction generator. Consider capacitive VAr to be a source and inductive VAr to be a sink of reactive power. Which one of the following statements is TRUE?




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17. Question

In a constant V/f induction motor drive, the slip at the maximum torque 




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18. Question

a 3-phase,2-pole,50Hz, the synchronous generator has a rating of 250MVA,0.8 pf lagging. The kinetic energy of the machine at synchronous speed is 1000MJ. The machine is running steadily at synchronous speed and delivering 60MW power at a power angle of 10 electrical degrees. If the load is suddenly removed, assuming the acceleration is constant for 10 cycles, the value of the power angle after 5 cycles is 




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19. Question

A 3-phase,50Hz generator supplies power of 3MW at 17.32kV to a balanced 3-phase inductive load through an overhead line. the per phase line resistance and reactance are 0.25Ω and 3.925Ω respectively. If the voltage at the generator terminal is 17.87 kV, the power factor of the load is




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20. Question

A 3- phase, 50Hz generator supplies power of 3 MW at 176.32 kV to a balanced 3-phase inductive load through an overhead lin. The per phase line resistance and reactance are 0.25Ω and 3.925Ω respectively. If the voltage at the generator terminal is 17.87 kV, the power factor of the load is 




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