North Maharashtra University 2010 B.E Instrumentation Technology Jalgaon, T.E,Instrumentation - exam paper

Seat No.___________

POWER ELECTRONICS(New)


Time:3 Hours Max.Marks:100
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Istructions: 1)Attempt any 2 sub-questions from every unit.

2)Illustrate your ans with neat diagrams and nesessary
waveforms.

3)Assume suitable data if necessary.
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UNIT-I


1. a)Describe differrent modes of operation of thyristor with help of static U-I
characteristics [Marks10]

b)Describe briefly subsequent members of thyristor family

i) LASCR ii) SUS

iii)SCS iv)PUT [Marks10]


c)Describe different anode voltage ratings applicable to SCR.Indicate this
voltage ratings on relevant voltage waveform. [Marks10]



UNIT-II


2. a)Explain principle of phase control using SCR with necessary waveforms. [Marks10]



b)Explain class C class D commutation along with waveforms. [Marks10]


c)Classify inverters. discuss any 1 kind of it. Comment on characteristic of
good inverter. [Marks10]




UNIT-III


3. a)Discuss main kinds of choppers.Which of these is more commonly used and
why? Enumerate applications of dc choppers. [Marks10]


b)What is multiphase chopper? With suitable waveforms discuss in phase and
phase shifted operation of multiphase choppers. [Marks10]


c)Design speed control circuit for single phase induction motor using waveform. [Marks10]



UNIT-IV


4.a)Explain single phase voltage controller with RL load. [Marks10]


b)Explain principle of single phase to single phase step up. Cycloconverter with
voltage and current waveforms. [Marks10]


c)Write note on resistance welding. [Marks10]



UNIT-V


5.a)What is static circuit breaker? discuss AC and DC circuit breakers. [Marks10]


b)Design light dimmer circuit using Triac. State applications of dimmer circuits. [Marks10]


c)Write short note on: [Marks10]


i)Over voltage protection circuit

ii)Zero voltage switch

Earning:   Approval pending.