Wednesday, October 29, 2014

Question Paper of EE52 Electrical Machines - II Fifth Semester Anna University Trichy, B.E EEE November December 2011

ANNA UNIVERSITY OF TECHNOLOGY, TRICHY

B.E./B.TECH. DEGREE EXAMINATION, November/December 2011

FIFTH SEMESTER - EEE

ELECTRICAL MACHINES II

Time : Three hours Maximum : 100 Marks

Answer ALL Questions

PART A - (10 X 2 = 20 Marks)

1. Define distribution factor.

2. What is damper winding? Why is it used?

3. Why does the synchronous motor develop torque only at synchronous speed?

4. What is a phase advancer?

5. Why three phase induction motor called singly excited motor?

6. Define slip.

7. How can speed of three phase induction motor be controlled?

8. What is induction generator?

9. Define step angle.

10. How will you change the direction of rotation of a split phase induction motor?

PART B - (5 x 16 = 80 MARKS)

11. a. Explain in detail MMF method of predetermining the voltage regulation of the alternator. (8)

b. A 4 -pole 3 phase, 50 Hz star connected alternator has 60 slots, with four conductors per slot. Coils are short pitched by three slots. If the phase spread is 60°, find the line induced voltage for a flux per pole of 0.943 Wb distributed sinusoidally in space. All the turns per phase are in series. (8)

12. a. Derive the expression for synchronizing current, power and torque. (10)

b, Calculate the maximum load on a 5 MVA, three phase alternator having a synchronous reactance of 5 ohm can deliver when connected to 6.6 kV bus bar if its excitation is such that the emf on open circuit is 6 kV. Find the armature current and power factor at this load. (6)

13. a. Derive an expression for power developed in a synchronous motor. (8)

b, A 3300 V, 1.5 MW, 3-phase Y connected synchronous motor has X d = 4 ohm per phase and Xq = 3 ohm per phase. Neglecting all losses, calculate the excitation EMF. When motor supplies rated load at unity PF. Calculate the maximum mechanical power would develop for this field excitation. (8)

Duraimani

B.E Civil Engineer Graduated from Government College of Engineering Tirunelveli in the year 2016. She has developed this website for the welfare of students community not only for students under Anna University Chennai, but for all universities located in India. That's why her website is named as www.IndianUniversityQuestionPapers.com . If you don't find any study materials that you are looking for, you may intimate her through contact page of this website to know her so that it will be useful for providing them as early as possible. You can also share your own study materials and it can be published in this website after verification and reviewing. Thank you!