Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 6th Sem New 2160913 Control Of Electrical Drives Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (New) EXAMINATION ? WINTER 2019
Subject Code: 2160913 Date: 12/12/2019
Subject Name: Control of Electrical Drives
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.
MARKS
Q.1 (a) What is an Electric Drive? Give the classification of Electric
Drive.
03
(b) Draw the basic block diagram of Electric Drive and Explain the
function of any three blocks.
04
(c) Explain nature and classification of load torques. 07
Q.2 (a) Explain the method to determine the moment of Inertia (J). 03
(b) Explain drive parameters for the load with rotational motion. 04
(c) Discuss the four quadrant operation of electrical drive for hoist
load.
07
OR
(c) Explain how static rotor resistance control is achieved during
starting of induction motor.
07
Q.3 (a) A 200V DC series motor has armature and field resistance of 0.2
? and 0.1? respectively. It takes a current of 20 A from supply
while running at 1300 rpm. If an external resistance of 2 ? is
added in series with the motor, calculate the new speed. Assume
load torque remains constant.
03
(b) Draw and explain the dynamic model of DC motor. 04
(c) Discuss the Single phase fully controlled converter for
continuous conduction mode with diagram and waveforms. Also
derive the equation for speed in terms of firing angle.
07
OR
Q.3 (a) A 200 V, 875 rpm, 150 A separately excited DC motor has an
armature resistance of 0.06 ?. It is fed from a single phase fully
controlled rectifier with an AC source of 220 V, 50 Hz. Calculate
the firing angle for rated motor torque and 750 rpm. Assume
continuous conduction mode.
03
(b) Compare DC Drive with AC Drive. 04
(c) Discuss chopper controlled Separately excited DC motor drive
operation for motoring mode.
07
Q.4 (a) Compare CSI fed induction motor drive with VSI fed induction
motor drive.
03
(b) Discuss the effect of harmonics on induction motor. 04
(c) Explain closed loop slip control scheme for induction motor. 07
OR
Q.4 (a) Explain operation of doubly fed induction machine in sub
synchronous mode.
03
(b) What are the advantages of V/f control over other scalar control
techniques?
04
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (New) EXAMINATION ? WINTER 2019
Subject Code: 2160913 Date: 12/12/2019
Subject Name: Control of Electrical Drives
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.
MARKS
Q.1 (a) What is an Electric Drive? Give the classification of Electric
Drive.
03
(b) Draw the basic block diagram of Electric Drive and Explain the
function of any three blocks.
04
(c) Explain nature and classification of load torques. 07
Q.2 (a) Explain the method to determine the moment of Inertia (J). 03
(b) Explain drive parameters for the load with rotational motion. 04
(c) Discuss the four quadrant operation of electrical drive for hoist
load.
07
OR
(c) Explain how static rotor resistance control is achieved during
starting of induction motor.
07
Q.3 (a) A 200V DC series motor has armature and field resistance of 0.2
? and 0.1? respectively. It takes a current of 20 A from supply
while running at 1300 rpm. If an external resistance of 2 ? is
added in series with the motor, calculate the new speed. Assume
load torque remains constant.
03
(b) Draw and explain the dynamic model of DC motor. 04
(c) Discuss the Single phase fully controlled converter for
continuous conduction mode with diagram and waveforms. Also
derive the equation for speed in terms of firing angle.
07
OR
Q.3 (a) A 200 V, 875 rpm, 150 A separately excited DC motor has an
armature resistance of 0.06 ?. It is fed from a single phase fully
controlled rectifier with an AC source of 220 V, 50 Hz. Calculate
the firing angle for rated motor torque and 750 rpm. Assume
continuous conduction mode.
03
(b) Compare DC Drive with AC Drive. 04
(c) Discuss chopper controlled Separately excited DC motor drive
operation for motoring mode.
07
Q.4 (a) Compare CSI fed induction motor drive with VSI fed induction
motor drive.
03
(b) Discuss the effect of harmonics on induction motor. 04
(c) Explain closed loop slip control scheme for induction motor. 07
OR
Q.4 (a) Explain operation of doubly fed induction machine in sub
synchronous mode.
03
(b) What are the advantages of V/f control over other scalar control
techniques?
04
2
(c) Explain constant air gap flux control scheme for induction motor
drives.
07
Q.5 (a) Write advantages of BLDC motor over conventional DC motor. 03
(b) Compare Direct torque control method and field oriented control
method.
04
(c) Explain the d-q model of induction motor. 07
OR
Q.5 (a) State application of synchronous motor drive. 03
(b) State the advantages and disadvantages of electric traction
drives.
04
(c) Explain basic structure of solar and battery operated drives. 07
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This post was last modified on 20 February 2020