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Narayanaguru Siddhartha College of Engineering

The document is a model exam for the subject "Special Electrical Machines" covering various types of electric machines including synchronous reluctance machines (SYRM), stepper motors, switched reluctance motors (SRM), permanent magnet brushless DC motors (PMBLDC), and permanent magnet synchronous motors (PMSM). The exam has two parts: Part A contains 10 short answer questions worth 2 marks each and Part B contains 5 long answer questions worth 16 marks each. The long answer questions provide options to answer conceptual questions or derivations related to the construction, working principle, torque equations, and control of the electric machines.

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55 views1 page

Narayanaguru Siddhartha College of Engineering

The document is a model exam for the subject "Special Electrical Machines" covering various types of electric machines including synchronous reluctance machines (SYRM), stepper motors, switched reluctance motors (SRM), permanent magnet brushless DC motors (PMBLDC), and permanent magnet synchronous motors (PMSM). The exam has two parts: Part A contains 10 short answer questions worth 2 marks each and Part B contains 5 long answer questions worth 16 marks each. The long answer questions provide options to answer conceptual questions or derivations related to the construction, working principle, torque equations, and control of the electric machines.

Uploaded by

krsheyam deephan
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOC, PDF, TXT or read online on Scribd
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Narayanaguru Siddhartha College of Engineering

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING


MODEL EXAM
Subject Code/Name: EE6703/Special Electrical Machines
Sem/Year: 07/04 Date: 10-10-2017
Marks: 100 Time: 1PM 4PM
Answer all Questions
PART-A (10x2=20Marks)
1. What is meant by reluctance torque in SYRM?
2. Write down the applications of SYRM?
3. Define lead angle?
4. What is the need of suppressor circuits in Stepper motor?
5. What is the need of rotor position sensor in SRM?
6. Write four applications of SRM?
7. What are the merits of BLDC drives?
8. Write the difference between electronic and mechanical commutator?
9. Classify the different types of PMSM?
10. Differentiate sine wave and square wave motor?

PART-B (16X5=80 Marks)

11 a) Explain the construction, working and types of SYRM? (16)


[OR]
b) Draw the phasor diagram and derive the torque equation of SYRM? (16)
12 a) i) Explain multi stack construction of stepper motor? (8)
ii) Explain modes of excitation of stepper motor with diagrams? (8)
[OR]
b) i) A stepper motor has resolution of 180 steps/rev. Find the pulse rate required in order to obtain a rotor
speed of 2400rpm? (8)
ii) Explain in detail the static and dynamic characteristics of a stepper motor? (8)
13 a) i) Explain with neat diagram; the microprocessor based control of Switched reluctance motor. (10)
ii) Derive the expression for static torque in SRM. (6)
[OR]
b) i) Explain with neat diagram any two converter topologies for SRM? (8)
ii) Explain the torque speed characteristics of SRM in detail. (8)
14 a) Explain the construction and principle of operation of PMBLDC motor. (16)
[OR]
b) i) Explain in detail the power controllers for PMBLDC? (8)
ii) A BLPM motor has noload speed of 6000rpmwhen connected to a 120v dc supply.The armature
resistance is 2.Determine the speed when supply voltage is 60V and torque is 0.5N-m. (8)
15 a) Derive the torque equation of PMSM with phasor diagram? (16)
[OR]
b) i) Derive the EMF equation of PMSM? (8)
ii) Explain the torque speed characteristics of PMSM? (8)

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