1.a) Discuss the constructional details of synchronous machine.[7]
b) Mention the differences between salient pole and non salient pole synchronous machine. [8]
2. Derive the emf equation of alternator, explain the coil span factor, distribution factor and derive the expressions? [15]
3.a) What are the causes of harmonics in the voltage waveform of an alternator?
b) Enumerate various methods used for minimizing harmonics in turbo-alternator.
c) Explain the effect of “armature reaction” in alternators for lagging power factor load, with mmf diagram. [15]
4. A 3-phase, star-connected alternator is rated at 1600 kva, 13500v. The armature effective resistance and synchronous reactance are 1.5Ω and 30Ω respectively per phase. Calculate the percentage regulation for a load of 1280kw at power factors of 0.8 leading 0.8 lagging. [15]
5. Two three-phase alternators operate in parallel. The rating of one machine is 50MW and that of the other is 100MW. Both alternators are fitted with governors having a droop of 4%. How will the machines share a common load of 100MW?
[15]
6. Explain V – curves and ∧ - curves of 3-phase synchronous motor. [15]
7. Explain the double field revolving theory of single phase induction motor. [15]
8. Explain the operation of universal motor. [15]
b) Mention the differences between salient pole and non salient pole synchronous machine. [8]
2. Derive the emf equation of alternator, explain the coil span factor, distribution factor and derive the expressions? [15]
3.a) What are the causes of harmonics in the voltage waveform of an alternator?
b) Enumerate various methods used for minimizing harmonics in turbo-alternator.
c) Explain the effect of “armature reaction” in alternators for lagging power factor load, with mmf diagram. [15]
4. A 3-phase, star-connected alternator is rated at 1600 kva, 13500v. The armature effective resistance and synchronous reactance are 1.5Ω and 30Ω respectively per phase. Calculate the percentage regulation for a load of 1280kw at power factors of 0.8 leading 0.8 lagging. [15]
5. Two three-phase alternators operate in parallel. The rating of one machine is 50MW and that of the other is 100MW. Both alternators are fitted with governors having a droop of 4%. How will the machines share a common load of 100MW?
[15]
6. Explain V – curves and ∧ - curves of 3-phase synchronous motor. [15]
7. Explain the double field revolving theory of single phase induction motor. [15]
8. Explain the operation of universal motor. [15]
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