# Pune University Question Papers Industrial Drives and Control

B.E. (E & TC) INDUSTRIAL DRIVES & CONTROL (2008 Pattern) (Elective – I) (Sem. – I)

Time :3 Hours]                                                                           [Max. Marks :100

Instructions to the candidates:-

1)            Answer three questions from section I and three questions from section II.

2)            Answers to the two sections should be written in separate books.

3)            Neat diagrams must be drawn wherever necessary.

4)            Figures to the right indicate full marks.

5)            All questions carry equal marks.

7)            Use of logarithmic tables, slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed.

8)            Assume suitable data, if necessary.

SECTION – I

QI) a) What are phase controlled converters? Explain with circuit diagram 8 waveforms working of 3^, full controlled converter with level food. Comment on p. f. 

b) A 3 phase converter operating from a 3 415v, 50Hz supply is feeding a inductive load. The current is continuous 8 ripple free equal to 100A. Find the thyrister ratings.    

OR

Q2) a) What are dual converters? Explain with circuit diagram 8 waveform working of 1^ dual converter with suitable load. Deduce equation for circulating current.  

b)           What is DC to DC converter? Explain Buck converter with circuit diagram 8 waveform.                                                                                                                              

Q3) a) What are inverters? Explain with circuit diagram 8 waveform working 3^ (transistorized) voltage source inverter in 180° conduction mode, (star load). 

b) What are different types of Harmonic reduction techniques? Explain any one type.     

OR

Q4) a) What are resonant converters? Explain with circuit diagrams 8 waveforms, working of zero voltage switching.                                                                          

b) What is cycloconverter? Explain with principle of operation, working of 1^ to 1^ cycloconverter. Draw suitable waveforms.                                            

Q5) a) What are DC Motor performance parameters? Explain in brief. 

b)        What is Soft start? Explain.                                                                      

c)         What is series motor? Explain with circuit diagram 8 waveform working of lc() series motor using highly inductive load. Comment on Torque speed c^S ■*           

OR

Q6) a) What is the need of reversible drives? Explain with diagram 8 waveforms, working of 4 quadrant chopper drive with suitable load. Comment on p.f. 

b) What is dynamic braking technique? Explain.                                         

SECTION – II

Q 7) a) What is the need of AC drives? Explain with block diagram, speed control

techniques of 1^, Induction motor by using

b) What are different types of protection circuits? Explain.                       

OR

Q8) a) What is slip power recovery in I.M.? Explain with circuit diagram working of static krammer system. Comment on Tq, speed •                                               

b) What is acceleration 8 decelleration? Explain.                                         

Q9) a) What are stepper motors? State the advantages of hybrid stepper motor over variable reluctance 8 permenent magnet stepper motor. List the drive requirement of stepper motor.                                                                                               

b) What is Load commutated inverter? Explain.                                                  

OR

QI0) a) What are synchronous Motor? Explain with diagram, working 8 speed control technique of synchronous motor. Comment on Tq, speed characteristics. 

b) What is CSI? Explain.                                                                                                                                       

QII) a) What are traction drives? Explain with block diagram. Comment on its Tq 8 speed characteristics.                                                                                                    

b)        What is power quality? Explain different types of powerline disturbances. State its preventive 8 nullifying techniques.                                                               

OR

Q12) Write short notes on any Three:                                                           

 a) Brushless DC motor. b) Z-source inverter c) Energy audit d) Dual mode Dual converter. e) Solid state relays (AC or DC) f) Fuzzy logic based Im speed control.