November 1, 2011

EE1202 ELECTRICAL MACHINES-I question papers Anna university question papers Download


B.E/B.Tech DEGREE EXAMINATION, NOVEMBER/DECEMBER 2006
Fourth Semester
Electrical and Electronics Engineering
EE 1202 --ELECTRICAL MACHINES-I
(Regulation 2004)
Time: Three hours                                                    Maximum marks: 100
Answer ALL questions
PART A (10 x 2 =20 marks)

1.Write the applications of singly excited and doubly excited magnetic systems.
2.Explain the following terms with respect to rotating electrical machines.

(a) Pole-pitch

(b) Chording angle

3.What are the conditions to be fulfilled for a DC shunt generator to build up emf?
4.What are the two functions of a commutator in DC machines?
5.What is the need for starter in a DC motor?
6.Why is a DC series motor used to start heavy loads?
7.Why transformer rating is expressed in terms of KVA?
8.What are the various types of three-phase transformer connections?
9.Give the expression for the load current when the transformer operates at its maximum efficiency.
10.Define 'all-day efficiency' of a transformer.

PART B (5 x 16 = 80)


11 (i)Draw and explain the general block diagram of an electromechanical energy-conversion device. (8)
(ii)Explain with the help of neat diagram about the nature of the magnetic field produced when a three phase supply is connected across a three phase winding. (8)
(or)
(b) (i)Show that the net eletromagnetic torque developed is zero if the rotating electrical machine has different number of poles on its stator and rotor. (8)

(ii)Derive an expression for torque developed in a 2-pole round rotor machine and state the assumptions made.(8)

12.  (a)(i).Derive an expression for the emf generated in the armature winding of a DC machine. (8)
(ii).A long-shunt compound generator delievers a load current of 50 A at 500 V and has armature,series field and shunt field resistances of 0.05 Ω,0.03 Ω and 250 Ω respectively.Calculate the generated voltage and the armature current.Allow IV per brush for contact drop.
(or)
(b)(i).Explain the effect of armature reaction in a DC generator.How are its demagnetising and cross-magnetising ampere turns calculated?(8)

(ii)Two seperately-excited DC generators are connected in parallel and supply a load of 200 A.the machines have armature circuit resistances of 0.05Ω and 0.1Ω and induced emfs of 42 V and 440 v respectively.Determine the terminal voltage,current and power output of each machine.The effect of armature reaction is to be neglected.(8)

13 (a)(i) Describe the working of athree-point starter for a DC shunt motor,with the help of neat diagram. (8)

(ii)Explain the field-flux control and armature contol methods of speed control of a DC shunt motor.(8)
(ii)Explain the field-flux control and armature control methods of speed control of a DC shunt motor.(8)
(or)
(b) (i)Explain the speed-torque characteristics of DC shunt and DC series motors. (8)

(ii)A 230 V,DC shunt motor,takes an armature current at 3.33A at rated voltage and at a no-load speed of 1000 r.p.m.The resistances of the armature circuit and field circuit are 0.3Ω and 160Ω respectively.The line current at full load and rated voltage is 40A.Calculate,at full load,the speed and the developed torque in case the armature reaction weakens the no-load flux by 4% (8)

14. (i)Draw and explain the no-load phasor diagram of a single phase transformer. (8)
(ii).Derive expression for the current shared by two transformersoperating in parallel,with unequal no-load voltages.(8)
(or)
(b) (i)Obtain the equivalent circuit of a 200/400 V,50 Hz,single phase transformer from the following test data:

O.C.Test:200V,0.7 A,70 w-on L.V side

S.C Test:15 V,10 A,85 w-on H.V side (8)

(ii)Expalin the principle of operation of an auto-transformer (8)

15. (a) (i)Explain the various losses which takes place in a DC machine (8)
(ii)A 500 V,DC shunt motor takes a total current of 5 A when running unloaded.The resistance of armature circuit is 0.25Ω and the field resistance is 125Ω.Calculate the efficiency and output when the motor is unloaded and draws a current of 100A. (8)
(or)
(b) (i)Explain the Hopkinson,s test for determining efficiency of two similar DC shunt machines (8)

(ii)Explain how the efficiency of a single phase transformer is estimated from the open circuit and short circuit test (8)

FEEL USEFUL PLEASE GIVE +1

0 comments :

Post a Comment

Get Syllabus in your Mail

Labels

Accenture Admission Notice - 2010 Admission Notification Anna University Anna University Chennai Anna University Question Papers Anna University Trichy Apparel Technology and Management Aptitude Questions Arts and Science Colleges Biomedical Engineering C and CPP Ebooks Calicut University CBSE Question papers Civil Engineering Civil Service Exams Colleges in India Colleges Result Computer Science Engineering Core Jobs CS R2008 CSE CSIR NET EBooks Download ECE EEE EIE Electives Electrical and Electronics Engineering Electronics and communication Electronics and Instrumentation Engineering Engineering Engineering Colleges in Maharashtra Engineering Colleges in TamilNadu Engineering Admissions Engineering Colleges Engineering Colleges in Karnataka Engineering Jobs Engineering Syllabus Entrance Exam Dates Entrance Exam Results Entrance Examination Exam Time Table Experiencer First Year Syllabus Freshers Full Time Jobs Government jobs in india Hardware and Networking Jobs Hotel Management and Catering Technology IGNOU Information Technology INTEVIEW QUESTIONS IT Jobs JNTU Question Papers Jobs in Bangalore Jobs in Chennai Jobs in Coimbatore Jobs in Delhi Jobs in Hyderabad Jobs in India Jobs in Kerala Jobs in Noida Jobs in Tamilnadu Jobs in TATA Karnataka Educations Lab Manuals Mechanical Engineering Medical Colleges Placement Papers Plus 2 Preparation for exams Private Jobs in India Question Papers Question Papers Download Results Announcement Semester 1 Semester 2 Semester 3 Semester 4 Semester 5 Semester 6 Semester 7 Semester 8 Syllabus Syllabus Download Tamil Movie TCS Placement Papers Teaching Jobs TECH MAHINDRA Textile Technology Top colleges University Results UPSC VICEVESVARAYA TECHNOLOGICAL UNIVERSITY waec Walk-in Interview Web Designers

Followers

Archive

Anna university Engineering Syllabus

Earn Money From Online

Government jobs in india

Admission Notification

Total Pageviews

 

Privacy Policy
http://topengineeringcollegesintamilnadu.blogspot.com use third-party advertising companies to serve ads when you visit our website. These companies may use information (not including your name, address, email address, or telephone number) about your visits to this and other websites in order to provide advertisements about goods and services of interest to you. If you would like more information about this practice and to know your choices about not having this information used by these companies, click here.