Download GTU B.Tech 2020 Winter 7th Sem 2171707 Industrial Drives And Control Question Paper

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Subject Code:2171707

GUJARAT TECHNOLOGICAL UNIVERSITY

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BE- SEMESTER-VII (NEW) EXAMINATION - WINTER 2020

Subject Name:Industrial Drives and Control

Time:10:30 AM TO 12:30 PM

Instructions:

1. Attempt any FOUR questions out of EIGHT questions.

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

Q.1

1. (a) Why do we require drive circuit to run the motor? MARKS 03
2. (b) Explain the effect of DC motor back emf on performance of drive circuit. MARKS 04

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3. (c) With appropriate block diagram, explain cascade control in DC motor closed loop control. MARKS 07

Q.2

1. (a) Discuss the selection criteria for electric motor drive MARKS 03
2. (b) Explain the electro-mechanical modeling of DC motor drive. MARKS 04
3. (c) Explain four quadrant operation of DC motor drive using chopper circuit. MARKS 07

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Q.3

1. (a) Where do we require chopper based drive? MARKS 03
2. (b) Draw and explain closed loop control of chopper drive. MARKS 04
3. (c) Give output voltage waveform of full wave controlled rectifier, driving DC shunt motor, for 30 degree firing angle. MARKS 07

Q.4

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1. (a) Draw any appropriate circuit to convert line voltage into chopper input voltage of 100 VDC. MARKS 03
2. (b) Explain the principle of operation of chopper in brief. MARKS 04
3. (c) Give output voltage waveform of full wave controlled rectifier, driving DC shunt motor, for 60 degree firing angle. MARKS 07

Q.5

1. (a) Draw basic voltage inverter circuit with resistive load MARKS 04

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2. (b) Draw practical sources for voltage source inverter and current source inverter. MARKS 07
3. (c) Explain with necessary circuit diagram, the working of modified half bridge Macmurray voltage source inverter MARKS 03

Q.6

1. (a) Explain why power factor is high in induction motor ? MARKS 04
2. (b) With block diagram explain induction motor speed control with variable speed PWM. MARKS 07

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3. (c) What is the limitation of cyclo converter based induction motor drive ? Suggest and explain any other scalar control method for induction motor. MARKS 03

Q.7

1. (a) Draw torque v/s angular displacement characteristic curve for 3 phase VR step motor MARKS 04
2. (b) What is micro stepping in step motor? Why is it required? MARKS 07
3. (c) With necessary circuit diagram and waveforms, explain recovery at high voltage drive for step motor. MARKS 04

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Date:19/01/2021

Total Marks: 56

Q.8

1. (a) Draw torque v/s angular displacement characteristic curve for 4 phase PM step motor MARKS 03
2. (b) List out essential components of DC servo control MARKS 04

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3. (c) With necessary circuit and waveforms, explain zener + resistance type and capacitor suppression drive for step motor. MARKS 07