ர 02000EE202052003 Pages: 2

Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

Fourth semester B.Tech examinations (S), September 2020

Course Code: EE202
Course Name: SYNCHRONOUS AND INDUCTION MACHINES (EE)

Max. Marks: 100 Duration: 3 Hours
PARTA
Answer all questions, each carries 5 marks. Marks
Graph sheets may be supplied
1 Derive the expressions for ‘Distribution factor' and prove that distribution factor (5)

approaches a constant value as number of slots/pole increases.

2 Explain the EMF method of determining voltage regulation of an alternator. (5)

3 Explain the effects of change in excitation when two alternators are connected (5)
in parallel.

4 A 2 pole, 3-phase Induction motor runs at 2910 rpm on ೩ 50117 supply. Find (i) (5)
synchronous speed and (ii) frequency of rotor emf.

5 Describe the constructional feature of double cage induction motor to obtain (5)
large starting torque.

6 Explain how the shunt parameters of the equivalent circuit of a 3-phase (5)

Induction motor can be obtained from no-load test.

7 Explain the principle of operation of an Induction generator. (5)
8 Explain the working of shaded pole motor. (5)
PART छ

Answer any two full questions, each carries 10 marks.
9 a) Derive the expression for pitch factor. Also find the value of short pitching (6)

angle to eliminate fifth harmonics completely.
b) Derive the emf equation of an alternator. (Expressions for pitch and distribution (4)

factors need not be derived)

10 A 3-phase, 4-pole, star connected alternator has a smooth cylindrical type rotor. (10)
The effective resistance and synchronous reactance per phase are 0.15Q and
2.5Q respectively. Calculate the voltage regulation when delivering 250 A at
6.6 kV at different power factors of (i) 0.6 pf lagging. (ii) upf (110.8 pf
leading.

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