Anna University Chennai 2005 B.E Electrical and Electronics Engineering SOLID STATE DRIVES EE-432 - Question Paper

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2005

7th Semester

Electrial and Electronics Engineering

EE 432 - SOLID STATE DRIVES
Time : 3 hours Maximum : 100 marks
ans ALL ques.


PART - A [MARKS 10 x two = 20]

1. Classify teh drive motors based on their speed torque characteristics.

2. List the factors that govern the option of rating of a motor to be used as a drive element.

3. What is meant by critical speed in phase controlled dc drives?

4. What causes poor input power factor in phase controlled dc drives?

5. What is the need for constant v/f ratio in variable voltage induction motor drives?

6. Sketch the mechanical characteristics of a 3 phase induction motor with v/f control.

7. provide the expression for torque of a static rotor resistance controlled 3 phase induction motor.

8. Where are closed loop control schemes of induction motors preferred?

9. Name the various modes of operation of a synchronous motor drive.

10. What is meant by brushless excitation?


PART - B (5 x 16 = 80)

11. (i) Build up the speed torque curves of a DC series motor with shunted armature connection. [MARKS 5]

(ii) Distinguish ranging from constant torque and constant H.P. operations of a DC motor. [MARKS 3]

(iii) discuss how you would determine the power rating of an electric motor when it is subjected to
continuous duty and variable load. [MARKS 8]


12. (a) (i) define a speed control scheme for a spearately excited dc motor using a single phase half
controlled thyristor bridge converter. [MARKS 8]

(ii) A separately excited dc motor is supplied from a 230 Volts 50 Hz source through a single
phase half wave controlled rectifiers. Its field is fed through a single phase semiconverter with
zero degree firing angle delay. The motor armature resistance is 0.7 ohms and motor constant

Earning:   Approval pending.