# GTU B.E 5th Semester Electromechanical Energy Conversion 2012 Question Paper

Looking for GTU Old Question Papers ? Look at the following question paper which presents 5th Semester B.E  Electromechanical Energy Conversion Winter 2012 Question Paper.

Seat No.: ________ Enrolment No._________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE – SEMESTER V • EXAMINATION – WINTER - 2012
Subject code: 152001 Date: 11-01-2013
Subject Name: Electromechanical Energy Conversion
Time: 02:30 pm to 05:00 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 various types of magnetic materials. 07
(b) Explain flux of an electric field through a surface. 07
Q.2 (a) Explain various effects of air gap in ferromagnetic circuits. 07
(b) Derive the expression for magnetic field due to current in straight wire 07
OR
(b) State and explain Ampere’s and Biot-Savart’s law. 07
Q.3 (a) Explain energy stored in capacitor and energy density in electric field with suitable expressions
07
(b) Derive the equation for the force density of attraction of the magnetic field on the armature 07
OR
Q.3 (a) Write a short note on electromagnet. 07
(b) A steel ring has a mean diameter of 20 cm and a cross section of 25 cm^2 and a radial air gap of 0.8 mm is cut across it. When excited by a current of
1 A through a coil of 1000 turns wound on the ring, it produces an air gap flux of 1 mWb. Neglecting leakage and firing, calculate relative permeability of steel and total reluctance of the magnetic circuit.
07
Q.4 (a) Explain working of an induction motor with suitable diagrams. 07
(b) Explain construction & working of an elementary generator. 07
OR
Q.4 (a) What do you mean by rotating magnetic field? Explain the rotating magnetic field in three phase A.C. motor with necessary diagrams.
07
(b) Explain magnetization characteristics of DC machine. 07
Q.5 (a) Explain: Self excited D.C. generator and separately excited D.C. generator. 07
(b) Explain reluctance motor. 07
OR
Q.5 (a) Why single phase induction motor is not self started? Explain the methods used to start the single phase induction motor in brief. 07
(b) Discuss the synchronous machine (from construction and working point of view). 07