直流电机培训资料

maxonDCmotor AdvantagesofcorelessDCmotorsThemaxonDCmotorPrograms RE A max RE maxConstructionandworkingprincipleCommutationsystemsBearingsystems Dr UrsKafader maxonmotorag Sachseln Schweiz maxonDCmotor Variants A max MotorwithAlNiComagnetpreciousmetalbrushessinteredsleevebearing RE MotorwithNdFeBmagnetgraphitebrushesballbearing CorelessmaxonDCmotor A max el connections flange housing magn return commutator plate shaft winding preciousmetalbrushes permanentmagnet commutator sinteredsleevebearing CorelessmaxonDCmotor RE30 el connections self supportedwinding commutator brushes permanentmagnet inthecenter housing magn return ConventionalDCmotor el connections housing magn return winding commutator brushsystem ironcore permanentmagnet attheperiphery Corelesswindingsystems maxon FaulhaberPortescap Quelle Portescap MautheKodak corless DC slotless EC Advantagecoreless nocogging nosoftmagneticteethtointeractwiththepermanentmagnetsmoothrunningevenatsmallspeedslessvibrationandnoiseanyrotorpositioncanbecontrolledinasimplewaynononlinearcontrolbehaviour Advantagecoreless noironlosses noiron noironlossesconstantmagnetizationhighefficiency uptoabove90 lownoloadcurrent typical 50mAdoesnotapplytoECmotorsnosaturationeffectsintheironcoreEvenatthehighestcurrentstheproducedtorqueremainsproportionaltothemotorcurrent strongermagnets strongermotors Advantagecoreless smallinductance lessbrushfirecommutation openandcloseacontactonaninductiveloadhigherliveexpectancylesselectromagneticemissionseasiertosupressinterferences capacitybetweenconnectionsferritecoreatmotorcablebutfastreactionofthecurrentproblemsincombinationwithpulsedsupply chokeneeded Advantagecoreless compactdesign moreefficientdesignofthemagneticcircuit eveniftheairgapislarger morecompactmagnetinthecenterhigherratioofpowertovolumesmallrotormassinertiahollowcylinderagainstfullcylinderhighdynamicstypicalaccelerationtimes 5 50ms S F RE A RE max maxonDCmotor Program year200019951990198519801970 A max rolledhousing magnet plasticflange design NdFeB AlNiCo Ferrite designandproduction magnet maxonDCmotor Programs permanentmagnetFerriteAlNiCoNdFeBmotorprogramFmotorA max S ARE RE maxmotorexample2130GBA max19GBRE13GBDn DM mNm min 1 115011501250assign power3W2 5W3Wmotorsize diameter30mm19mm13mmlength33mm29mm34 5mmcont torque3 3mNm4 4mNm3mNm 23 3cm3 4 6cm3 8 2cm3 Stator themagneticcircuit housing magneticreturnpathmadeofsteel iron guidesmagneticfield airgap thelargertheairgap theweakerthemagneticfield permanentmagnet producesmagneticfieldwithnorthandsouthpolesonoppositesides Developmentofpermanentmagnets NdFeB SmCo AlNiCo SmFeN steel Ferrit year max energyproduct kJ m3 max energyproducttheoreticallimit960kJ m3technicallyachievableca 720kJ m3 Permanentmagnets B T 1 21 00 80 60 40 2 H kA m 900800700600500400300200100 magnetCurieoperationmotordesigntemperatureNd2Fe14B310 C110 170 Call ECSm2Co17825 C350 CSmCo5720 C250 CAlNiCo 850 C550 Conlycorelessferrite450 C250 350 Cconventional Constructionofrotors commutatorplate commutator windingconnections winding shaft commut plate winding commutatorwire epoxy shaftwithknurling bondage Winding enameledwire lacquer plasticwithsolvantatenhancedtemperature 130 150 C plasticmeltsandconnectsneighbouringwires pressingformsthebodyinnarrowtolerances outgassingofsolvant plastichardens bakingofthewinding copperwire lacquer insulation coppercore goodelectricalconductorinsulation noshortcircuits knittedmaxonwindingknittedwindingforbigmotorswithNdFeBmagnetREmotors ECmotorsthickwalledwindings standardmaxonwinding maxonwinding standardandknitted Currentflowinmaxonwinding Forceandtorqueproduction rhombiccurrentareas magneticfieldinairgap force magneticreturn force Torqueandcurrent torqueconstant forces forceoncurrentleadingconductorinamagneticfield torque sumofallforcesatthedistancetotherotatingaxis influencingparameters geometryfielddensitywindingnumbercurrentI design application currentdirectiontowardsflange force force currentdirectiontowardsbrush magneticfield Speedandvoltage speedconstant windingrotatesinairgapwithinhomogeniousmagneticfieldinducedvoltageUind backEMF dependingongeometrymagneticfielddensitywindingnumberspeednspeedconstantkninverselyproportionaltokMinverselyproportionaltogeneratorconstant V 1000rpm design application Brushcoveradjustingatno load adjustingthebrushsystemrotatinguntiloptimumcommutation commutationpictureformaximummotorlifeno loadcurrent measureoffrictionthehighertheload friction thehigherthe no load currentfrictioninbearingandcommutationfaults e g touchingwinding misalignedbearingsno loadspeed measureofmagnetandwindingbadmagnet impropermagnetization higherno loadspeedtoostrongamagnet lowerno loadspeeddependsonvoltageandmagneticfieldintheairgaphigherappliedvoltage higherspeed Commutationpicture 1 ripple2 modulationbecauseofasymmetricalwinding3 currentsignalofarevolution Commutationprocess 14 15 25 26 36 37 47 41 51 52 62 63 73 74 14 Torqueripple commutatorcommut torquesegmentspointsripple5105 6614 7142 5 9181 5 11221 13260 75 5 14 DCcommutationsystems preciousmetalbronzebrushbodywithplatedsilver withpalladium contactareasilvercoppercommutatorsmallcontactandbrushresistance 50mW CLLforextendedservicelife graphitegraphitebrushwith50 coppercopperreducescontactandbrushresistancegraphiteactsaslubricantspring DCcommutation rotors glasfibrebondage coppercommutator scotchbondage CLLdisc silvercommutator 2shaftends preciousmetal graphite DCcommutation contactresistance terminalresistance Rwind IAcurrent Rmot IAcurrent terminalresistance RmotRwind Rmot I preciousmetal graphite 50mW theproblemsolutioncapacitancebetweenneighbouringcommutatorsegmentsenergyisdeviatedintocapacitance noarcsproduced Preciousmetalcommutation CLL aftershortcircuit arcproductioncommutatorwearsoff Preciousmetalcommutation CLL time short circuit aftershort circuit withoutCLL energyisgivenawayveryrapidly highvoltages sparks withCLL energyisgivenawayslowlydampedoscillationlowvoltages 10V 200V voltagebetweenthecommutator segments LifetestingofCLL 2 5005 0007 50010 000h Motor2017 941I 50mAn 13 000rpmU 24V 108642 CLL testterminated 5101520 x1000h 108642 CLL Motor2140 935I 250mAn 1 500rpmU 10V DCcommutation prosandcons graphitewellsuitedforhighcurrentsandcurrentpeakswellsuitedforstart stopandreversedoperationbiggermotorshigherfriction higherno loadcurrentsnotwellsuitedforsmallcurrentsmoreaudiblenoiseandelectromagneticemissionmoreexpensive preciousmetalwellsuitedforsmallestcurrentsandvoltageswellsuitedforcontinuousoperationsmallermotorsverylowfrictionandnoiselowelectromagneticemissionfavourablepricenotwellsuitedforhighcurrentsandcurrentpeaksnotwellsuitedforstart stopoperation maxonDCmotor servicelife lifeinfluencingfactorstheelectricload highercurrents higherelectricwear arcing speed higherspeed highermechanicalweartypeofoperation reversedoperation reducedservicelifetemperaturehumiditywithgraphitebrushesCLL withpreciousmetalbrushes enhancesservicelifeloadonshaft bearings servicelifenogeneralstatementpossibleaverageconditions 1 000 3 000hoursunderextremeconditions lessthan100hoursunderfavourableconditions morethan20 000hours usegraphitebrushesandballbearingsforextremeoperatingconditions ballbearing smallfriction rollingballsenhancedbyaxialpreloadordisbalancewithlubricantsuitableforheavyloadsforcesactonballsforlargermotorshighernoiselevelthansleevebearingsmoreexpensive loadontoshaft sinteredsleevebearing materiallubricantbetweengrains upto30 ofvolumelubricantreservoirdependsonbearingsizeviscosityandporesizemustbetunedfunctionathighspeeds hydrodynamicallubricationatlowspeed directcontactofshaftandbearingmechanicallowerloadsthanballbearingforsmallermotorslowernoiselevelthanballbearinglowercosts shaft sinteredsleevebearing lubricant hydrodynamicallubrication smallradialload asymmetricalpressurehigherspeedslubricantcircuitnohydrodynamiclubricationat highradialloadsdirectcontactofshaftandbearingtiltedbearings wobblingshaft friction speed viscousfriction 250rpm mixedfriction bearing maximumaxialloads dynamicaxialloadmaximumpermissibleforcealongshaftaxisduringoperation dynamic press fitforce static maximumpermissib