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Question Paper Code : I-1382

B.E.lB.Tech. DEGREE EXAMINATION, NOVEMBER/DE CEMBER 20L2.

Third Semester

Mechatronics Engineering

EE 3205 - ELECTRICAL MACHINES AND DRIVES

(Begulation 2008)'

Time : Three hours Maximum : 100 marks

AnsWer ALL questions.

1. State Kirchoffls voltage Law.

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2. What is power factor?

3. What is the basie principle of operation of universal motor?

, 4. Defrne Step,angle in stepper motor.

5. List the speed control methods for DC motor. :

,, h. Draw the equivalent circuit for an induction motor.

7. Draw the block diagram of an electric drive.

\/ 8. List the advantages of an electric drive.

9. Defi,ne the term slip power

10. List the advantage and disadvantage of v/f control in induction motor.

. PART B - (5 x 16 = 80 marks)

11. (a) Explain the operation of chopper fed separately excited. d.c drive withnecessary waveforms. (1G)

Or

(b) Explain the operation with waveforms for voltage across arrhature V" andcurrent through armature i" for an fully controlled rectifier fed dc drive.

.S. frl ,Derive the e:cpressio$s f,or-torque artd speed of DC shunt and series motorand draw the characteristics. i

Write short note on :

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(, What is the need for starters? (4)

(ii) Draw and explain the different types of starters for dc motor. (12)

Or

(b) Dg.lcribe !$.,various starting ryetfroas of ttrree phase induction motor

(b)

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(b)

15.- (a)

(i) Desigp the thermal model of a motor for heating arrd cooling withneeessar?equations. , (10)

(O State and explain the disadvantages of using a motor of wrongrating. i (6)

Or':Describe the different classes of motor duty for various load timings withneeessary examples. (16)

Explain the stator voltage control of three phase induction motor usingAC voltage regulators: .(16)

(b) Discuss the operation of static Scherbius drive for recovery of slip power.(16)

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