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1、可编程控制答案Problemset2Whatarethecommontypesofelectricalcontrolsystem?Solution:thegeneralelectricsystemdiagramincludesthreekinds:electricalschematicdiagram,electricalarrangementdiagramandinstallationwiringdiagram.Describetheprincipleofdrawingelectricalschematics・Solution:payattentiontothefollowin
2、gprinciples:(1)theelectricalschematicdiagramofeachelectricelementsinthegraphicsymbolsandtextsymbolsaccordingtothecorrespondingnationalstandarddrawingandlabel,thesamefunctionofelectricalcomponentsshoulddrawtogether,butthesameelectricalcomponentsnotnecessarilydrawtogether・Alltheelectricalcompo
3、nentsonthelayoutdrawnseparatelyaccordingtothefunction,suchasmaincircuit,controlcircuit,lightingcircuit,signalcircuitandprotectioncircuit,etc・,inaccordancewiththe"fromlefttoright,fromtoptobottom"theorderofarrangement,andasfaraspossibleinorderofmovement・(2)electricalschematicdiagramoftheelectr
4、icalcomponents,powercord,touchthetopareunified,asstipulatedinthestandardofgraphicsymbolandtextsymbolsofnationalstaridard.Thethree-phaseacpowersetisdrawnupabovethesurfaceofthepicture,insequencefromtoptobottom,LI,L2,L3,neutral(N),andprotectedground(PE)belowL.Thecontactstatesofeachelementaredra
5、wninthestateoftheelectromagneticcoilsornoexternalforces・Whenthegraphicsymbolofthecontactisplacedvertically,itisdrawnontheprincipleof"leftopenright7',thatis,thedirectionofthecontactheadisalwaysleft,oftenclosedandtheheadisclosedtotheright・Thehorizontalpositionisdrawnundertheprincipleof"upperan
6、dclosed",whichisthetendencytoopentheheadinthedirectionofthehead,andkeeptheheadingdownward.(1)inthecircuit,the"hollowcircle"isusedfortheconnectionpointsthatneedtobetestedandcanberemoved.Theconnectionpointsofaconductiveconnectionarerepresentedbythe"solidcircle";Withoutconductingwireintersectio
7、ns,thelinesshouldbeavoidedinthecircuitdrawing.(2)electricalschematicdrawingrequirementsdistinct,reasonablearrangementoftheelectricalcomponentsandcontact,toensurethatbothwiththeleastamountofelement,theleastamountofwire,theleastcontact,andtoensuretha