Rajasthan Technical University 2009-8th Sem B.E : Electrical Engineering (B.Tech- ) Advance Electical Machine - Question Paper
Rajasthan tech. University kota
Electrical Engineering (B.Tech. - semester 8)
Advance Electrical Machine
8207
Pfepcr IV(w)
IV B.E. (VIII SEMESTER) (MAIN/BACK) EXAMINATION, 2M9
(New Four Year Semester Scheme)
[Branch : Electrical Engineering]
Paper IV(iv)
Time Allowed : Three Hours Maximum Marks80
I /) No supplementary answer-book will be given to anv candidate. Hence the candidates should write the answer precisely in the Main answer-book only.
(2) All the parts of one question should be answered at one place in the answer-book. One complete question should not be answered at different places in the
answer-book.
Turn ovtr
Attempt any five questions.
Alt questions carry equal marks.
1. (a) Explain the concept of equal area criterion. Explain the applications of equal area criterion to study transient stability for the following cases: (i) A sustained line fault
(ii) A line fault cleared after the lapse of ccrtain time by the simultaneous opening of ci niit breakers at both ends of the line. 8 (b) Define various reactances and time constants of.; . synchronous machine. 8
2. (a) What do you mean by short circuit ratio of a
synchronous generator? Show that it is equal to the reciprocal of per unit value of direct axis synchronous reactance. 8
(b) Explain the phenomenon of sudden 3-phase short-circuit at the armature terminals of the alternator. Draw a typical waveshape of current and mark the different regions. Write an expression for the current. 8
i
3. (a) Explain the working principle of stepper motor.
How does a stepper motor ' differ ffom a conventional motor?- Explain the working of 2 phase, 4/2 pole permanent magnet stepper motor in detail. 8
(b) Explain the principle of working of homopolar induction alternator with neat diagram. 8
4. (a) Explain the concept of vector controlled motors
in detail. 8
(b) Explain the concept of brushless motor in detail with the help of proper diagrams. 8
5. (a) Explain the principle of operation of a linear
induction motor. Draw its characteristics. State its important applications. 8
(b) Describe the construction, working and uses of a reluctance motor. 8
6. (a)' Explain the three phase transformer connections
and its phasor groups. 8
(b) Explain how three phase in a transformer is' converted to 6 phase. 8
7. (a) Explain the phenomenon of over voltage in trans
formers in detail. 8
(b) Explain the transient behaviour of a transformer in detail. 8
8. Write short notes on any two of the following:
(a) Hysteresis Motor
(b) Excitation phenomenon in transformers
(c) Effects of unbalanced currents in 3-phase transformers. 8x2=16
S207
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| Earning: Approval pending. |
