Download GTU BE/B.Tech 2019 Winter 7th Sem New 2171707 Industrial Drives And Control Question Paper

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Seat No.: Enrolment No.

GUJARAT TECHNOLOGICAL UNIVERSITY

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BE - SEMESTER- VII (New) EXAMINATION - WINTER 2019
Subject Code: 2171707 Date: 23/11/2019
Subject Name: Industrial Drives and Control
Time: 10:30 AM TO 01:00 PM Total Marks: 70

Instructions:

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1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Why PWM inverter used to control speed of Induction motor? Explain in brief. 03
(b) Explain various drive circuits for the stepper motors, in brief. 04

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(c) Discuss the basic working theory of DC servo motor. Find its governing equation and transfer function also. Derive state space modeling of DC motor drive with block diagram. 07

Q.2 (a) Why is the duty cycle usually changed by varying the on time rather than the chopping frequency? Explain in brief. 03
(b) Discuss brushless DC motor and its speed control strategy. 04
(c) Draw the waveforms of 1st Quadrant chopper operation for DC motor drive & Explain with relevant calculation. 07
OR

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(c) Draw the waveforms of 3rd Quadrant chopper-operation for DC motor drive & Explain with relevant calculation. 07

Q.3 (a) Explain torque versus stepping rate characteristics for Stepper motor. 03
(b) Discuss the Merits and Demerits of Volts/ Hz control strategy for AC drive . 04
(c) Explain Chopper principle used-in electrical drive with circuit, waveform and equation. 07
OR

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Q.3 (a) List out important features of the stepper motors. 03
(b) Discuss the static frequency changers for AC motor drive, in brief. 04
(c) Compare the performance features of six step and PWM control of Voltage-source inverter in terms of Harmonics, control complexity and ease of implementation. 07

Q.4 (a) State essential parts of Electrical drives. 03
(b) What are factors that limit the high frequency operation of DC chopper switching operation? 04

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(c) Explain the operation of a Variable Reluctance stepper motor. 07
OR
Q.4 (a) What are the main factors which decide the choice of electrical drive for a given application? 03
(b) Discuss the various measuring scheme for motor constants with diagram/calculation for DC motor, in brief. 04
(c) Design a Digital controller for a hysteresis current control for DC chopper drive. 07

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Q.5 (a) What are the functions of Power modulator? 03
(b) Explain multi-pulse modulation technique for the induction motor, in brief. 04
(c) What do you mean by DC servo motor closed loop speed control ? Explain it with diagram. 07
OR
Q.5 (a) Explain operation of Permanent Magnet stepper motor, in brief. 03

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(b) Discuss in brief, Phase Locked Loop (PLL) control of the DC motor drive with block diagram. 04
(c) Explain the operation of half-bridge modified McMurray inverter. 07

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