Download GTU BE/B.Tech 2017 Winter 7th Sem New 2171707 Industrial Drives And Control Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER-VII (NEW) EXAMINATION — WINTER 2017

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Subject Code: 2171707 Date:02/11/2017
Subject Name: Industrial Drives and Control
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) Listout different selection criteria for the electrical drive. 03
(b) Obtain the state space model of the DC machine. 04
(c) Explain methods to measure the different DC machine constants. 07

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Q.2 (a) Explain shunt motor with its torque-speed characteristics. 03
(b) A series operated DC machine has 1.5 HP, 220V, 1600 rpm, armature 04
resistance of 3Ω, field resistance of 1Ω, frictional coefficient of 0.002
Nm/(rad/sec) and mutual inductance of 0.0675H. Find (i) air gap torque
(ii) armature current (iii) armature voltage.

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(c) The separately excited DC machine has rating of 1200 KW, 500V, 2200 07
A, 400 rpm with brush drop of 3V, field power 35KW and armature
resistance of 0.003Ω. It has variable armature voltage and fixed field
current. Derive (i) Frictional torque with frictional coefficient 10
Nm/(rad/sec) (ii) Back EMF constant (iii) Input power (iv) Efficiency.

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OR

(c) Draw and explain equivalent circuit of DC machine. Derive the equation 07
of electromagnetic torque.

Q.3 (a) Draw the waveforms of 1st quadrant chopper operation for DC motor 03
drive.

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(b) Explain closed-loop speed control-using DC drives. 04
(c) Explain the half-wave controlled rectifier based drives of DC motor with 07
necessary waveforms and derive output voltage equation.

OR

Q.3 (a) Explain principle of operation of the chopper. 03

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(b) Draw the waveforms of 3rd quadrant chopper operation for DC motor 04
drive.
(c) Explain with waveforms fully controlled rectifier based DC motor drive. 07

Q.4 (a) Explain multi-pulse modulation technique for the induction motor. 03
(b) Give properties of PWM waveforms. Explain PWM inverters. 04

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(c) Explain PWM and HCC hysteresis chopper based closed operation of DC 07
motor drive.

OR

Q.4 (a) Explain constant volts/Hz control for induction motor. 03
(b) Explain different input way to the chopper. 04

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(c) Explain the operation of half-bridge modified McMurray inverter. 07

Q.5 (a) Draw and explain torque versus stepping rate characteristic of stepper 03
motors.
(b) Explain construction and working of VR stepper motors. 04
(c) Explain brushless DC motor. 07

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Q.5 (a) Listout important features of the stepper motors. 03
(b) Explain DC servo control. 04
(c) Explain drive circuits for the stepper motors. 07

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