EE010706L06 Special Electrical Machines B.Tech Model Question Paper : mgu.ac.in

Name of the College : Mahatma Gandhi University
Department : Electrical and Electronics Engineering
Subject Code/Name : EE 010-706L06/Special Electrical Machines
Sem : VII
Website : mgu.ac.in
Document Type : Model Question Paper

Download Model/Sample Question Paper :
I : https://www.pdfquestion.in/uploads/mgu.ac.in/5096-1-MQEE706L06-1.pdf
II : https://www.pdfquestion.in/uploads/mgu.ac.in/5096-2-MQEE706Lo6-2.pdf

MGU Special Electrical Machines Question Paper

Btech Degree Examination, November 2013 :
Seventh Semester
Branch- Electrical and Electronics Engineering

Related : MGU MEEPP105-3/MMEPE105-2 Robotics & Automation M.Tech Model Question Paper : www.pdfquestion.in/5054.html

EE 010-706L06 : Special Electrical Machines
Model Question

Paper -I

(Regular- New Scheme)
Time : Three Hours
Maximum- 100 Marks

Part A :
Answer all questions briefly :
Each question carries 3 marks :
1. Define step angle and what is meant by half step mode of operation of stepper motors.
2. Explain with block diagram the control scheme of switched reluctance stepper motor.
3. Explain the concept of torque production in synchronous reluctance motor

4. What is the requirement of position sensors in permanent magnet brushless DC motors (PMBLDC)? Mention any two types of position sensors used in permanent magnet BLDC.
5. Draw the phasor diagram of a permanent magnet synchronous motor

Part B :
Each question carries 5 marks :
6. With neat diagram explain the constructional features of variable reluctance stepper motors.
7. Define the hard chopping and soft chopping methods of control used in switched reluctance motors.

8. Explain the principle of operation of synchronous reluctance motor.
9. Explain in detail the constructional features of permanent magnet brushless DC motors (PMBLDC). Draw the schematic diagram of PMBLDC motor with control mechanism.

10. Explain how a sinusoidal rotating magnetic field is produced in the stator of a permanent magnet synchronous motor

Part C :
Answer any one full question from each module :
Each full question carries 12 marks :
MODULE I :
11. A 3 phase variable reluctance stepper motor is used of a particular application in which the step angle has to be varied in the following manner in anti clockwise direction. 30o-15o-30o-15o and so on from the reference axis. With neat figures explain its operation.
Or

12. (a) Explain with neat figure the dynamic characteristics of stepper motors
(b) What is meant by micro stepping mode of operation of stepper motors? What are its advantages?

MODULE II :
13. Explain in detail any three characteristics curves of switched reluctance motor.
Or
14. (a) What is the requirement of chopping/hysterisis control of switched reluctance motor? What is meant by single pulse mode control of switched reluctance motor

(b) Draw the block diagram of switched reluctance motor drive system. With neat figures of inductance profile explain the operation of switched reluctance motor

MODULE III :
15. With neat figure explain the speed control of synchronous reluctance motor.
Or
16. Derive the expression for torque for a synchronous reluctance motor and explain its torque speed characteristics.

MODULE IV :
17. Explain in detail the torque speed characteristics of permanent magnet brushless DC motors with torque expression.
Or
18. With the timing diagrams discuss the operation and characteristics of permanent magnet brushless DC motors. Draw the truth table for six step commutation including hall sensor status, phase current and power output.

MODULE V :
19. Derive an equation for power developed in permanent magnet synchronous motor and analyze the effect of direct and quadrature axis reactance on developed power.
Or
20. Describe with neat sketches the construction details and operation of a permanent magnet synchronous motor with speed control.

Paper – II

Btech Degree Examination, November 2013 :
Seventh Semester :
Branch- Electrical and Electronics Engineering
EE 010-706L06 : Special Electrical Machines
Model Question Paper -I : (Regular- New Scheme)
Time : Three Hours
Maximum : 100 Marks
Part A :
Answer all questions briefly
Each question carries 3 marks
1. Define stepper motor and its step angle
2. Distinguish between switched reluctance motor and variable reluctance stepper motor

3. List down any three comparisons between switched reluctance and synchronous reluctance motor

4. Compare brushless DC motor with conventional DC motor
5. Explain the principle of operation of permanent magnet synchronous motor with its basic constructional features

Part B :
Each question carries 5 marks
6. What is meant by two phase excitation of stepper motors? Mention its advantages.
7. Explain with neat figure the inductance profile of switched reluctance motor. Explain each region in its profile.

8. Explain the principle of operation of synchronous reluctance motor.
9. Define commutation in DC motors. Explain in detail the electronic commutation used in BLDC motors
10. Derive the emf equation of a permanent magnet synchronous motor.