DR.
BABASAHEB AMBEDKAR TECHNOLOGICAL UNIVERSITY, LONERE
Supplementary Winter Examination – 2024
Course: B.TECH Branch : Electrical Engineering/Electrical Engg(Electronics & Power)/
Electrical & Electronics Engg/ Electrical & power Engineering
Subject Code & Name: BTEEC703 Electrical Drives Semester : VII
Max Marks: 60 Date:10/02/2025 Duration: 3 Hr.
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Instructions to the Students:
1. Each question carries 12 marks.
2. Question No. 1 will be compulsory and include objective-type questions.
3. Candidates are required to attempt any four questions from Question No. 2 to Question No. 6.
4. The level of question/expected answer as per OBE or the Course Outcome (CO) on which the
question is based is mentioned in ( ) in front of the question.
5. Use of non-programmable scientific calculators is allowed.
6. Assume suitable data wherever necessary and mention it clearly.
(CO) Mark
Q. 1 Objective type questions. (Compulsory Question) 12
1 Which of the following is NOT a typical part of an electrical CO1
drive?
a) Power b) Electric c) Control d) Heat exchanger
modulator motor unit
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2 Which of the following is a multiquadrant operation? CO1
a) Forward b) Forward c) Reverse d) All of the
motoring braking motoring above
3 Load equalization in drives is achieved by: CO2
a) Increasing b) Using c) Improving d) Increasing
motor power flywheels insulation supply voltage
4 In steady-state operation, the drive operates under conditions CO2
of:
a) Constant b) Varying c) Maximum d) Zero feedback
speed and acceleration load
torque variations
5 Current limit control in drives ensures that: CO2
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a) The drive b) Motor c) Speed d) Feedback is
operates at current does remains minimized
maximum not exceed constant
efficiency safe limits
6 Static Kramer drives are typically used for: CO3
a) Low b) c) Single- d) Enhancing
power Controlling phase motors motor braking
applications the speed of
slip ring
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induction
motors
7 Which type of DC motor drive is most suitable for dynamic CO3
braking?
a) Single- b) Dual c) DC-DC d) Half-wave
phase full converter converter drive
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converter drive drive
drive
8 Multiquadrant operation in induction motor drives requires: CO4
a) Stator b) Voltage c) Rotor d) Constant torque
voltage source resistance
control inverters variation
9 Load commutated inverters are typically used for: CO4
a) Starting b) Speed c) Reducing d) Braking
synchronous control of load applications
motors synchronous fluctuations
motors
10 Static variable frequency control for synchronous motors is CO4
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primarily used for:
a) High- b) Dynamic c) Energy- d) Constant
speed braking efficient frequency
operations operations applications
11 In textile mills, drives must primarily focus on: CO5
a) High b) Precise c) Reducing d) Operating at
torque at low speed control power losses fixed speeds
speeds and torque
control
12 Which type of motor is typically used for kiln drives in CO5
cement mills?
a) b) Slip ring c) Permanent d) Single-phase
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Synchronous induction magnet AC motor
motor motor motor
Q. 2 Solve the following. 12
A) Draw block diagram of electrical drives and explain its different CO1 6
parts.
B) Explain four quadrant operation of motor driving hoist load. CO1 6
Q.3 Solve the following. 12
A) Write a brief note on classes of duty for on electric motor CO2 6
in on electric drive
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B) Describe with neat block diagram of Closed Loop Speed Control CO2 6
of Multi Motor Drives:
Q. 4 Solve Any Two of the following. 12
A) A 200 V, 875 rpm, 150 A separately excited de motor has an CO3 6
armature resistance of 0.06 Ω. It is fed from a single phase fully-
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controlled rectifier with an ac source voltage of 220 V, 50 Hz
Assuming continuous conduction, calculate
(1) firing angle for rated motor torque and 750 rpm
B) Explain breaking technique of DC motor in detail : CO3 6
1) Plugging 2) Regenerative breaking
C) Explain the working and characteristics of a single-phase full CO3 6
converter drive for controlling the speed of a DC motor.
Q.5 Solve Any Two of the following. 12
A) Explain operation of VSI fed induction motor drive. CO4 6
B) Discuss the Static Scherbius Drive for slip power recovery in CO4 6
induction motors. Explain its working with a block diagram.
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C) Explain the concept of voltage and frequency control for induction CO4 6
motor drives
Q. 6 Solve Any Two of the following. 12
A) Explain in brief drives required for various stages in textile mills CO5 6
B) Draw the block diagram of variable frequency control of multiple CO5 6
synchronous motor drive and explain in brief.
C) Explain the principle of static variable frequency control for CO5 6
synchronous motors. How does it affect speed and torque control?
*** End ***
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