Industrial Electronics- 1 marks- ECE-Polytechnic.pdf

7/22/2019 Industrial Electronics- 1 marks- ECE-Polytechnic.pdf

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Sukesh.R/ECE/Lecturer Industrial Electronics ECE/IV sem

UNIT-I

1.WhatisSCR?

SiliconControlled Rectifier isa three termin

als (Anode, C

athode

and G

ate), threejunction

and

fourlayersemiconductorswitchingdevice.

2. WhatisIGBT?

Insulated Gate Bipolar Transistor is a three terminal(Collector, Emitter, gate )power

semiconductordevice. Its a combination of BJT and MOSFET.Itisusedasanelectronicswitch

withhighefficiencyandfastswitching.

3. WhatisTriggeringofanSCR?

TriggeringisnothingbutturnedONprocessofanSCR.

TheSCRcanbetriggered(tunedON)anyoneofthefollowingmethods.

IncreasingforwardvoltagebeyondbreakdownvoltageVBO.

Applyingapositivevoltagetogatewithrespecttocathode(Gatecontrolmethod)

4. WhatisOptoCoupler?

Anoptocouplerusedtoisolatethelowpowercontrolcircuitryfromahighpowerload.

Itconsistsofalightsource,alightsensitivedeviceandaswitchingdevice.

OR

Transferring of an electrical energy between two circuits, without any physical contacts.

5.DefineHoldingCurrent.

It is the minimum anode current, below which SCR turned OFF.

6.DefineLatchingcurrentofanSCR.

Latchingcurrentistheminimumvalueofanodecurrentrequiredtokeep (continuous)theSCRinthe

ON stateafterthegatesignalisremoved.

7.Definedv/dtratingThe dv/dt rating of an SCR indicates themaximum rateof riseof anodevoltage that will not

triggertheSCRwithoutanygatesignal.

8.Definedi/dtrating.

Thedi/dtratingofanSCRindicatesthemaximumallowablerateofchangeofcurrentwhichtheSCR

canwithstandduringitsonstate.

9.HowisSCRturnedOFF?

Bygivingreversevoltagetothegate-cathodeterminal,theSCRwillturnOFF. By reducing anode current below holding current.

10.DefineforwardbreakovervoltageofSCR.

Theminimumforwardvoltagewithgateopen,atwhichSCRstartsconductingheavily(turnon)iscalledtheBreakovervoltage.

11.WhatisreverseblockingregioninSCR?

In the reversebiased condition, the reverse voltage is gradually increased, at aparticular voltage

avalanchebreakdownoccur.Theregionbeforebreakdowniscalledreverseblockingregion.

12.Whatisforwardconductionregion?

ByapplyingagatesignaltoSCR,itwillgoestoheavyconductionintheforwardbiasedcondition.This

regioniscalledasforwardconductionregion.

GRG POLYTECHNIC COLLEGE, COIMBATORE *~ALL THE BEST~* Page 1


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13.Mentionthetypesoftriggering.

ACgatetriggering

DCgatetriggering

Pulsedg

atetriggering

14. MentionanythreeapplicationsofSCR

Emergencylight

Automaticbatterychargercircuit

Largepowersupplies

Industrial Applications

15.MentionanythreeapplicationsofMOSFET

ElectronicDCrelay

Switchedmodepowersupply

Inductionheating


16.MentionanythreeapplicationsofIGBT

DCandACmotordrives.

Tractionmotorcontrol

UPSsystem


17.MentionanythreeapplicationsofGTO

Staticbreakers

Highpowerinverters

Deepseapumpdrives


18.M

entionanytworequi

rementsofagatet

rigge

ringci

rcuit

TheSCRshouldbeforwardbiased

Gateshouldbemadepositivewithrespecttocathode

19.Whataretheadvantagesofpulsetraintriggering?

Lowheatisproducedatthegate-cathodejunction.

Thesizeofgateisolationtransformerissmall.

Lowdissipationinreversebiasedstate.

20.WritethreeadvantagesofGTO.

GTOhasfasterswitchingspeed

Ithaslowersizeandweight&Ithashigherefficiency

No need of commutation circuit to turn off.

21.WhatisGTO?Drawitssymbol.

A Gate Turn off Thyristor is a special type of thyristor, a highpower semiconductor device. It

containsthreeterminals,namelyAnode(A),Cathode(K)andGate(G). It can be turned OFF by applying

Negative gate signal to gate.



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22.WhatisMOSFET?

Metal Oxide Semiconductor Field Effect Transistor is a very fast switching transistor. It has three

terminalscalleddrain(D),source(S)andGate(G).

23.ExpandLASCR,SBS, SUS.LASCR - LightActivatedSCR

SBS - SiliconbilateralSwitch

SUS - Silicon Unilateral Switch

24.WhatisPulsetransformer?

Pulse transformers are often used to couple a trigger pulse generator to a SCR, in order to obtain electrica

isolation between the two circuits.

25. Write the types of pulse triggering.

Single pulse triggering Pulse train triggering

26. Define triggering circuit or firing circuit

A circuit which used to Turn ON the SCRis called triggering circuit or firing circuit.

27. What is thyristor?

Thyristor is a power Semiconductor device. It derived from the properties of a THYRatron tube and a

TransISTOR. THYRISTOR = THYRatron + TransISTOR

28. List some devices on Thyristor family.

SCR Silicon controlled rectifier

IGBT Insulated gate bipolar transistor

GTO Gate turn off thyristor

MOSFET - MetalOxideSemiconductorFieldEffectTransistor

LASCR - Light Activated SCR

SBS - Silicon bilateral SwitchSUS- Silicon Unilateral Switch

29. Draw the symbols of SCR, IGBT, MOSFET and GTO

UNIT-II

1.WhatisConverter?

AcircuitusedforconvertingACintoDCiscalledconverterorrectifier.

2.WhatisControlledconverter?

A circuit used for converting AC into DC by using SCRs ispopularly known as a controlled

converter.

3.DefinePhasecontrolofanSCR.

AnSCRcanbeturned-ON atanyanglewithrespecttotheappliedvoltage,anditisknownasphase

control.



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4. WhatisCommutation?

Commutation is defined as the process of turning OFF a SCR. (or) Theprocess of transferring

conductionfromoneSCRtoanotherSCRistermedascommutation.

5.WhatisChopper

?AchopperisastaticdevicethatconvertstheinputDCvoltageintofixedorvariableDCoutput

voltage.

6.GivetwoapplicationsofDCchopper.

Electricautomobiles(batteryoperatedvehicle)

Trolleycars

Industrial applications

7.MentionthetwotypesofCommutation.

NaturalCommutation

ForcedCommutation

8.WhatisNaturalCommutation?(Linecommutation)

TheSCRwillbeturnedOFFduetothenaturalbehaviorofsourcevoltagei.e,thecurrentgoesthrough

naturalzero.ThesetypesofcommutationareknownasNaturalcommutationorLinecommutation.

9.WhatisForcedCommutation?

If the inputvoltageof SCR isDC, then its forwardcurrent is forced to zerobyusingacommutation

circuittoturnOFFtheSCR.ThistypeofcommutationiscalledasForcedCommutation.

OR

If the SCR is turned OFF by an External circuit then it is called as forced commutation.

10. WhatisanACchopper

Voltage changing circuits employing semiconductordevices as a static switch, areknown as AC

choppers.

11.WhatisFreewheelingdiode?

The flywheel or free wheel diode helps to turn OFF the SCR and improves load current

waveformandprovidehigherDCoutputvoltage.

12.WhatisDCchopper?

DCchopperconvertsdirectlyfromDCtoDCrelativelywithanewtechnology.

13.Mentionthetypesofphasecontrolledconverters.

a.Singlephaseconverters

b.Threephaseconverters

Eachoftheabovetypesisagainsubdividedinto

Semiconverter

Fullconverter

Dualconverter

14. Mentiontheadvantagesofthephasecontrolledconverters

Simplecircuit

Highefficiency

Lessexpensive.

15. Mentionthetypesofforcedcommutation

ClassAcommutation

ClassBcommutation



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ClassCcommutation

ClassDcommutation

ClassEcommutation

Class

Fcommut

ation

16.MentionthemethodstovarytheaverageoutputvoltageinDCchopper.

Variablefrequencycontrol

Constantfrequencycontrol

17. Define commutation circuit.

A circuit which uses to turn OFF the SCR is called Commutation circuit.

18. What is duty cycle.

Duty cycle () is an operating period of chopper. Its a ratio between Ton to (Ton + Toff).

Duty cycle() = Ton / (Ton + Toff)

19. Give the disadvantage of Johns chopper

SCRs with higher PIV rating is required.

20. How the SCR is turned OFF?

1) its anode current falls below the holding current

2) Applying reverse voltage to SCR

UNIT-III

1.Whatisaninverter?

DCtoACConvertersisknownasinverters.

2.Mentiontherequirementsofaninverter

Outputwaveformshouldbesinusoidal

Outputvoltage

shouldbecontroll

able

Itshouldbeabletooperatewithaninductiveload

Ithastooperatedevenwithoutload

3.Givetheapplicationsofinverter

VariablespeedACmotordrives

Emergencylightcircuits

Stand-bypowersuppliesforrelays


Stand-bypowersuppliesforcomputers

4.WhatisUPS?

Uninterruptablepowersupplycombinesapowersupplywithabatterytoprovideacircuitcan

provideoutputpowerwhiletheincomingpowerisdown.

It is a Stand by sources for critical loads where normal AC supplies are not available.

5.MentionthetypesofUPS.

OFF-lineUPS

ON-lineUPS



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6.GiveanytwodifferencebetweenonlineandofflineUPS

S.No. OFF-lineUPS ON-lineUPS

1. The inverter comes intoplay only when

theACmain

sf

ail

s

The inverter is always powered

irrespectiveoftheACm

ain

s

2. It introduces some delay during change

over frommain to inverter, and inverter

tomain

Nodelayduringchangeoverperiod.

7.MentiontheadvantagesONlineUPS

Always provide regulated output to load.

It protects the load from Surges, noise frequency vibrations

Inverter output frequency can be maintained at the desiredvalue.

8.Mentionthemethodstoobtainsinewaveoutputfromaninverter.

Resonatingtheload

Us

ingproperfilters

Usingpulsewidthmodulation

Usingsinewavesynthesis

Usingpoly-phaseinverters

9.Mentionthemethodstocontroltheoutputvoltagefromaninverter.

ControlofDCinputvoltageofinverter

ControlofACoutputvoltageofinverter

Controlofvoltagewithintheinverter

10.MentiontheadvantagesofMcMurrayinverter.

IndependenthalfcyclecontrolallowsPWMoperation.

Higherefficiencyatlightloadsisthusachieved.

Aportion of commutating energy is stored in an inductor and returned to thecommutating

capacitor.

Lowcommutationlossesatlowerloads.

11.WhatisSMPS?

Switched Mode Power Supplies provide regulated output voltage with more efficiency. They do no

requirethelargertransformersandfilteringdevices.

12.MentiontheadvantagesofDCtransmissionsystem.

Used for long distance electricity transmission

PoweroneachDCpoleisindependentlycontrollable.

Intermediateswitchingstationsarenotrequired.

Nocorona loss ADCsystemoffershighdegreeofreliabilityatreducedcost.

Noskineffect.

13.MentiontheadvantagesofSMPSoverlinearpowersupplies.

Forthesamepowerrating,SMPSissmallersizelighterinweightandpossesseshigherefficiency.

SMPSislesssensitivetoinputvariations.

14.MentionfiveapplicationsofSMPS.

Televisionsandmonitors.

PrintersandFAX machines.



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VCRsandportableCDplayers.

Computers.

Laptopandcamcorderpowerpacks.

15. What is HVDC(High Voltage Direct Current) transmissionHVDC is used for long distance electricity transmission. When comparing with AC transmission method

Additionally it uses converters for HVDC systems. It can transmit upto 2000V.

16. Mention the types of HVDC

1) Uni-polar HVDC it uses single conductor only.

2) Bi-polar HVDC it uses two conductors.

17. What is the need of control circuit in SMPS

Control circuit is consisting of feedback loop, Oscillator, comparator and duty cycle control. Control circuit

ensures the regulated output of SMPSby using above mentioned parts.

18. Expand SMPS, HVDC, UPS

SMPS - SwitchedModePowerSupplies

HVDC - High Voltage Direct Current

UPS - Uninterruptablepowersupply

19. What is meant by duty cycle control in SMPS?

Pulse Width Modulation technic is used for Duty cycle control. It vary pulse by pulseto provide

an accurate output voltage.

20. What is parallel inverter?

During the working of inverter , the commutating capacitor (C) comes in to parallel with the

loadis called Parallel inverter.

UNIT-IV

1.WhatisPLC?ProgrammableLogicController (PLC)isasolid state system, with a programmable memory for

storing instructions and implements specific functions such as logic, timing, sequencing and

arithmetic to control machines and processes.

2.Whatisarelay?

Relay isanelectrically operated deviceand it isused for controllinghighvoltage andcurrent

devices with a low voltage and current control signal. It may have NO and NC contacts or both the

combinations.

3.Whatisinputmodule?

Theinputdeviceslikepushbuttons,limitswitches,analogsensorsarewiredtoinputmodulewhichis

usedtogiveinputstotheprocessor.

4.MentiontheinputswitchingdeviceusedinPLC.

Limitswitches,

Pushbuttonsandanalogsensors.

5.MentiontheoutputdevicesusedinPLC.

Contactors,solenoidvalves,indicatorlightsandpositioningvalves.

6.WhatarethepartsofPLC?

Itconsistsoffiveparts.Namely, 1) Processorunit

2) Powersupply



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3) Memory

4) Input/outputsection

5) Programming Device

7.StateanytwoadvantagesofPLC. Flexibilityandlowercost

Implementingchangesandcorrectingerrors

Reliabilityandmaintainability

Easyofchangebyreprogramming

8.Whatisladderprogramming?

Relay ladderlogic isagraphical programming language for PLCs. The ladderdiagramlanguage i

basicallyasymbolicsetofinstructionsusedtocreatethecontrollerprogram.

8.StateanddrawANDlogicfunction.

InANDlogic twoormoreswitchesareconnectedinaserialmanner.Theswitchassemblyis

usedtocontroltheload.

9.Mentionthetypesofrelays.

i)Electromechanicalrelay

ii)Solidstaterelay

iii)Timingrelay

iv)Latchedrelay

10. GivethefeaturesofPLC.

i)Theinputandoutputstatusareindividuallyindicated

ii)Separatedisplaycommentsareavailable

iii)Itprovidesisolationbetweeninputandoutput.

11. GiveanytwodifferencebetweenPLCandhardwiredcircuit.

S.no. PLCcircuit Ha

rdwi

redci

rcuit

1. It is a programmable one. So

modificationiseasy.

Relays have to be hardwired to perform a

specificfunction.Somodificationisdifficult.

2. Powerconsumptionisreduced Power consumptionishigh

3. Very reliable operation Non- reliable

4. Speed of operation is High Speed of operation is Low

12. MentionthetypesofI/Omodule.

i)AnalogI/O ii)Digital(Discrete) I/O

13. What is timing relay (Timer)?

Timing relays are conventional relays , which used to provide time delayfor opening or closing the contacts.

14. What are the types timing relay OR Timer

1) ON delaytiming relay ( DOE- Delay On Energize)

2) OFF delaytiming relay (DODE- Delay On De-Energize)

15. What is ON delay?

When the supply is given to coil, the contacts changes its positions (NO/NC) after some delay. It also called

Delay on Energize(DOE).

16. What is OFF delay?

When supply is given to relay coil, the contacts areimmediately changes its position (NO/NC) and after some

delay it backs to its normal position.



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17. What is meant by latching or latching relay?

Latching is a process of hold the relayon ONcondition after power has been removed.

18. Give some examples of Analog input devices and digital input devices.

Example for Analog i/p devices Sensors, Temperature probesExample for Digital i/p devices Push buttons, Limit switches

19. Give some examples of Analog output devices and digital output devices.

Analog o/p devices Positioning Valves

Digital o/p devices Contactors, relays , solenoid valves

20. What is meant by Analog i/o and digital i/o modules?

Digital I/O sections are either ONor OFF / Energize orDe-Energize

Analog I/O sections it have infinite number of possible values

21. What is the use of processor in PLC?

Processor is a brain of a PLC. It reads and executesthe operations according to the instructions.

22. What is the need of memory device in PLC?

Memory device is used to stores the instructionsgiven in the programs. It uses ROM, RAM and EEPROM.

23. Write the types of Memory.

24. Draw the Symbols for Input and Output Device.

UNIT-V

1.Whatissteppermotor?

Steppermotorisamotorwhichrotatestepbystepinbothclockwiseandanticlockwisedirection.

2.DefineCNC.

ComputerNumericalControlperformsallthebasicfunctionbyprogram.Theprogramsarestoredinthe

memory. In CNC process involves a small digital computer.

3.Mentiontheapplicationofnumericalcontrol.

Drillingmachine

lathesandgrinders

System Memory (ROM)Application Memory

User instruction Memory (RAM) Variable Data Memory (EEPROM)

MEMORY



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Flamecutters

Millingmachines

4.WritetheadvantagesofNumericalcontrolsystems.

Highlyflexibleandeconomic

al.

Highaccuracyatallrangesofspeedsandfeeds.

Productiontimeislow.

Noneedofhighlyskilledoperator.

5.DefineNumerical Control (N/C).

Controlling a machine toolby apreparedprogram, which consists of series of numbers, isknown a

numericalcontrol. OR

A system which operations are controlled by insertion of numerical data.

6.Whatispartprogramming?

Theprogramiswrittenbyusingthecollecteddatasisknownaspartprogrammingwhichisdone

bythepartprogrammer.Thedatastakenfromthedrawingdimensions.

7.Writethestepsforpartprogramming?

Collectionofalldatarequiredtoproduceapart

Calculationofatoolpathalongwhichthemachineoperationswillbeperformed.

Arrangementofthealreadygivenandcalculateddatainastandardformat.

8.WhatisRobot?

Arobotisareprogrammable,multifunctionalmanipulatorwhicharecomputercontrolleddevices,i

performtasksusuallydonebyhumans.

9.MentionthedrivingdevicesusedinNumericalcontrolsystem.

LeadscrewforX-axisdrive,Y-axisdrive&Z-axisdrive.TheControlLogicUnit(CLU)operates

thedrivingdevicesofthemachineleadscrews.

10.M

entiontheadvantagesofRobots. Productivity &Speed

Quality

Production

Managementcontrol

11. MentionthepartsofPostprocessor.

Postprocessorconsistsof,

Inputelement

Motionelement

Auxiliaryelement

Outputelement

Controlelement

12. DefinePostprocessor.

Post processor is additional computer program. It generates output in a control tape or punched tape by

using standard peripheral devices.

Postprocessor translates theprocessed information from the computer into the coded instructions

necessaryforoperatingtheN/Csystem.



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13. MentionthetwodifferencesbetweenNCandCNC.

S.No. Numericalcontrol Computernumericalcontrol

1. Programstoredinpunchedtape Programstoredincomputermemory

2. Repeateduseofpapertapewilldestroyit Sinceprogramisstoredinmemorynosuchproblearises

3. Making changes in program is very difficult Making changes in program is vey easy.

14. Whatisinterpolator?

It supplies current velocity commandsbetween two datapoints taken from the drawing. For

complicated parts, the required additional data points will be calculated automatically by an

interpolator.

Interpolator permits the generation of circular, slope, and parabolic paths with high degree of

accuracy.

15. Whatarethevariouspostprocessorelements?

Input element Motion element Auxiliary element Output element Control element

16. Listthetypesoftapereader.

Mechanicaltype

Photoelectrictype

17. StatetheadvantagesofCNCsystem. Increasedflexibility

Reductioninhardwarecircuits

CNCiscompatiblewithDNC

18. What are the parts of Numerical Control(N/C) machine?

1) N/C program part (punched tape)

2) Machine Control Unit (MCU)

3) Machine

19. What are the parts of MCU (Machine control Unit)

1) Data processing Unit (DPU)

2) Control Logic Unit (CLU)

20. What is Data Processing Unit (DPU)?

Data processing unit receives the coded information from a tape, and it decodes it to the CLU.

21. What are the parts of DPU?

1) Data input device

2) Tape reader circuit

3) Decode circuits

4) Interpolator



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22. What are datas contains in DPU?

1)Position of each axis

2)Directions of motion

3)Auxiliary function4)Dimensions ( length, speed, width etc.,)

23. What is CLU ? and What are the units of CLU (control logic unit)?

CLU operates the driving devicesbased on the program punched in tape.

Units of CLU:

1) Position Control Loop

2) Velocity or Speed control loop

3) Auxiliary circuits

24. Mention some programming systems for Numerical control system (N/C)

1. APT Automatic programmed tools

2. ADAPT Adaption of APT

3. EXAPT Extended subset of APT

4. AUTOSPOT- Automatic system and positioning tools

5. AUTOMAP

6. AUTOPROMPT

7. CAMP II

8. SPLIT

25. What is meant by sprocket channel?

Series of equal width pulses, which produced from the punched tape. Sprocket holes are smaller than the data

holes.

26. Mention the types of data processing techniques on Part programming.

Manual Programming

Computer programming

27. What is manuscript?

Manuscript is a planning chart or list of instructions to describe the operations of machine.

Manuscript is typed with flexo writer on Punched tape or paper.28.Write the advantages of using computer for part programming?

1) Perform the mathematical calculations quickly and accurately

2) high reliability

3)Elimination of Human Errors

4) easy to program.

29.what are the parts of Motion element in Postprocessor?

1) Geometry package

2) dynamic package

30. What are the types of numerical control?

1) Computer numerical control(CNC)

2) Direct Numerical control (DNC)

3) Adaptive control (AC)

31. What is time based generator? What are the functions of Pulse generator?

Time based Generator (TMG) contains the main clock of 2.5MHz pulse generator for the system .

Functions of Pulse generator:

Direct feeding of control loops

Generating reference signals

Producing interrupt pulses



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32. How the computer is connected with the controller of CNC?

Controller is connected with computer by following lines:

Interrupt Input Lines

Digital Input LinesDigital output Lines

33. What are the three laws of Robotics?

1) A robot must not harm humans

2) A robot must obey a human being

3) A robot must protect itself from harm

12 MARKS

UNIT 1

1. Explain SCR2. Explain IGBT3. Explain MOSFET4. Explain GTO5. Explain Gate triggering methods6. Explain Pulse transformer triggering7. Explain opto isolator triggering8. Explain RC half wave triggering and RC full wave triggering methods9. Explain synchronized UJT triggering

UNIT 2

1. Explain single phase half controlled bridge converter with Resistive(R) load and RL load.2. Explain single phase full controlled bridge converter with Resistive(R) load and RL load.3.

Explain the importance of fly wheel diode

OR

Explain single phase bridge converter with RL load using Flywheel diode (Half controlled & Full controlled)

4. Explain Commutation and its types (6 Marks)5. Explain basic DC chopper operation6. Explain jones chopper (Typical chopper)7. Explain single phase AC chopper8. Explain Chopper using MOSFET

UNIT 3

1. Explain Single phase full bridge inverter with Resistive (R) load and RL load.2. Explain the methods to obtain sinewave from an inverter (6 MARKS).3. Explain the methods to output voltage control of an Inverter4. Explain McMurray inverters5. Explain parallel inverter using IGBT6. Explain HVDC transmission with its Types7. Explain SMPS8. Explain UPS with its types



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UNIT 4

1. Explain Relay with its types2. Explain PLC with neat block diagram3.

Explain basic Input and Output modules with neat diagrams

4. Draw ladder logic for LOGIC functions and explain it.5. Draw ladder logic for star delta starter and explain it.6. Draw ladder logic for conveyor control process and explain it.7. Draw ladder logic for Lift control process and explain it.

UNIT 5

1. Explain Numerical Control (N/C) System with neat block diagram.2. Explain Data processing Unit and Data reading Technique.

Or

Explain Data reading or Photo electric tape reader

3. Explain Part programming4. Explain Post processor with neat block diagram5. Explain CNC with Neat block diagram6. Explain basics of Robotics


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Industrial Electronics- 1 marks- ECE-Polytechnic.pdf