GTU BE 4th Semester 142401 Electro Mechanical Energy Conversion.- 1 Summer 2018 Question Paper

1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE – SEMESTER ?IV (OLD) – EXAMINATION ? SUMMER 2018
Subject Code: 142401 Date: 19/05/2018
Subject Name: Electro Mechanical Energy Conversion.- 1
Time: 10:30 AM to 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Explain the working principle of DC generator and derive the equation for
generated emf.
07
(b) Explain different parts of dc generator with neat sketches. 07

Q.2 (a) Why starter is necessary in DC Motor? Explain the working of three point starter
with neat diagram.
07
(b) Explain the internal and external characteristics of DC Shunt Generator. 07
OR
(b) Enlist various methods of speed control for DC shunt motor. Explain any two in
detail.
07

Q.3 (a) Explain the construction and working principle of three phase induction motor. 07
(b) Derive the equation of the starting torque and the condition for maximum torque
under running condition for 3-? induction motor.
07
OR
Q.3 (a) Explain the theory of production of rotating magnetic field in IM with 3-?
supply.
07
(b) Discuss various methods of measurement of slip for IM. 07

Q.4 (a) Derive EMF equation of a transformer. Prove the core loss is practically same
under all load condition.
07
(b) Explain the equivalent circuit of single-phase transformer. 07

Q.4 (a) Explain the short circuit test of 1-? transformer. State the reason for transformer
rating in KVA.
07
(b) List the conditions for the parallel operation of 1-? transformers. 07

Q.5 (a) Explain the parallel operation of 3-? Alternator. 07
(b) Explain the repulsion principle with the help of neat sketches. 07
OR
Q.5 (a) Explain the construction and working of Schrage motor with neat diagram. 07
(b) Explain the zero power factor methods for finding the voltage regulation of 3-?
alternator.
07
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