Exam Details

Subject Electrical Machines - Ii
Paper
Exam / Course B.Tech. VIEP- Electrical Engineering III (BTCSVI/BTECVI/BTELVI)
Department School of Engineering & Technology (SOET)
Organization indira gandhi national open university
Position
Exam Date December, 2016
City, State new delhi,


Question Paper

No. of Printed Pages: 3 IBIEE..Ol1I
B. Tech. -VIEP -ELECTRICAL ENGINEERING (BTELVI)
Term-End Examination
December, 2016
BIEE-011 ELECTRICAL MACHINES-II
Time hours Maximum Marks: 70
Note: Attempt any seven questions. Each question carries equal marks. Assume data, if any, wherever required. Use of scientific calculator is allowed.

1. Explain the terms coil-span factor and distribution factor in connection with alternator armature windings and deduce the e.m.f. equation of an alternator incorporating the effects of these factors. 10

2. Explain the phenomena of armature reaction when an alternator is delivering a load current at purely lagging p.f., unity p.f., purely leading p.f. 10

3. Explain the terms direct-axis synchronous reactance and quadrature-axis synchronous reactance of a salient pole alternator. Upon what factors do these values depend? 10

4. A 400 6-pole, 3-phase, 50 Hz, star connected synchronous motor has a resistance and synchronous impedance of 0.5 Q. and 4 Q. per phase respectively. It takes a current of 15 A at unity power factor when operating with a certain field current. The load torque is increased till the line current reaches 60 the field current remaining "Unchanged. Calculate the gross torque developed and the new power factor. 10

5. Explain the effect of varying excitation on armature current and power factor in a synchronous motor. Draw V-curves and state their significance. 10

6. What is the purpose of using deep-bar cage rotors Explain the construction and working of a deep-bar cage motor. 10

7. A double-cage induction motor has the following equivalent circuit parameters, all of which are phase values referred to the primary

Primary: R1 =1.0 Q X1 =2.8 Q
Outer Cage R2o' =3.0 Q. X2o'=1.0 Q.
Inner Cage R2i =0.5 Q. 5.0 Q

The primary is delta connected and supplied from 440 V. Calculate the starting torque, when running at a slip of 4%. The magnetizing branch can be assumed connected across the primary terminals. 10

8. Draw the circuit diagram: of a capacitor-start capacitor-run single-phase induction motor and explain its working. Where is such type of motor commonly used 10

9. Draw and explain a typical torque -speed characteristic of a reluctance motor. Compare a reluctance motor with an equivalent induction motor. 10

10. Write short notes on any two of the following: 2x5=10

Stepper Motors

Speed Control of 3-phase Induction Motors

Parallel Operation of two Alternators


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  • Centre for Corporate Education, Training & Consultancy (CCETC)
  • Centre for Corporate Education, Training & Consultancy (CCETC)
  • National Centre for Disability Studies (NCDS)
  • School of Agriculture (SOA)
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Subjects

  • Active Filter Design
  • Advanced Control System
  • Advanced Power Electronics
  • Applied Electromagnetics
  • Basics Of Electrical Engineering
  • Computer Process Control
  • Control System
  • Digital Electronics
  • Electric Energy Utilization
  • Electrical And Electronics Engineering Materials
  • Electrical Instrumentation
  • Electrical Machine - I
  • Electrical Machines - Ii
  • Electrical Machines And Electronics
  • Electrical Measurements And Measuring Instruments
  • Electro Mechanical Energy Conversion - I
  • Electro-Mechanical Energy Conversion - Ii
  • Electro-Mechanical Energy Conversion-Iii
  • Electromagnetic Theory
  • Energy Auditing And Analysis
  • High Voltage Engineering
  • Industrial Drives
  • Micro Controllers
  • Microprocessor And Applications
  • Network Theory
  • Power Quality Issues And Remedial Measures
  • Power System
  • Power System - I
  • Stochastic Control Systems
  • Switchgear And Protection