Download GTU BE/B.Tech 2018 Winter 3rd Sem Old 131901 Electrical Machines And Electronics Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER-III (OLD) EXAMINATION - WINTER 2018

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Subject Code:131901 Date:12/12/2018
Subject Name:Electrical Machines And Electronics
Time:10:30 AM TO 01:00 PM Total Marks: 70

Instructions:
1. Attempt all questions.

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2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Draw and explain the construction of a DC Machine. [07]
(b) Explain Internal and External characteristics of DC Shunt Generator [07]

Q.2 (a) Is DC Motor self-started? Why? Draw and Explain Three point starter. [07]

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(b) Sketch and explain the speed-current, speed-torque and torque-current characteristics of a d.c. shunt motor. [07]

OR

(b) Classify and Explain DC Generator with circuit diagram with terminal voltage and generated power equation. [07]

Q.3 (a) Explain production of rotating magnetic field in three phase induction motor. [07]
(b) Is Single phase induction motor self-starting? Why? Explain double field revolving theory for the same motor. [07]

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OR

Q.3 (a) Explain parallel operation of alternators. [07]
(b) Explain the construction features and working principle of single phase transformer [07]

Q.4 (a) Explain different speed control methods for DC Shunt motor. [07]
(b) What is power factor? Discuss the disadvantages of low power factor and explain the methods to improve power factor. [07]

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OR

Q.4 (a) Explain merits and demerits of overhead system and underground system for electric supply. Also compare A.C. and D.C. transmission system [07]
(b) What do you mean by Tariff? Explain different types of Tariff. [07]

Q.5 (a) Explain the full wave rectifier in detail with the help of circuit diagram and waveforms [07]
(b) Draw & Explain Internal architecture of 8085 microprocessor [07]

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OR

Q.5 (a) What is the purpose of substations in electrical power system? Explain briefly the function of following equipment in a substation: [07]
1) Bus-bar
2) Circuit Breaker
3) Isolator

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4) Lightning Arrester
5) Insulator
(b) What is Logic-Gate? Draw the Truth table & symbol for AND, OR, NOT, NOR Gate. Also State & Explain De-Morgan’s Theorem [07]