>> P.429
Ⅲ29ConsiderationofOperationPatternsIncaseoflinearmotordriveTheeffectivethrustforcemayexceedtheratedthrustdependingontheoperationrateofLinearMotorTable,leadingtomotoroverheatingandseizurethatmaycausebreakageandhumaninjury.Beforeoperations,ensurethattheeffectivethrustforceisbelowtheratedthrust.DescribedbelowisanexampleofconsiderationofoperationpatternwithLT170HS.TemporarilysettheoperationpatternasindicatedbelowconsideringthecarryingmassandaccelerationfromthedynamicloadmasschartinpageⅡ-306.SettingitemsModelLT170HS(naturalaircooling)MassofmovingtableWT4.0kgSeepageⅡ-319TablespecificationMaximumthrustattravelingspeedVFMAbout550NSeepageⅡ-306RunningresistanceFRSee[IncaseofLT…H]inthesectionofcalculationofmarginalaccelerationtime.SpeedcoefficientfVCarryingmassWL30kgTravelingdistanceL1.2mTravelingspeed(setspeed)V1.5m/sta0.3sTimetc0.5st2.5sCordpull-resistanceFc1.0NExpectedvalueFactorofsafetyk1.3Ambienttemperature30℃TimeTimettatctaFaFPFLLSpeedThrustforceVSTEP1Calculationofthrustforcerequiredforacceleration①ForcefromrunningresistanceFLFL=fV×FR+Fc=2.25×40+1=91N②ForcefromaccelerationFaVFa=(WL+WT)・ta1.5=(30+4.0)×=170N0.3③ThrustforcerequiredforaccelerationFPFP=Fa+FL=170+91=261NAtthispoint,checkthattheFP×k(factorofsafety)isbelowthethrustcharacteristicscurveinpageⅡ-306.Ifthisvalueisexceeded,reviewthemaximumspeedforoperatingpatternandacceleration/decelerationtime.Youcanseeintheexamplepatternthatitisbelowthethrustcharacteristicscurve.MaximumthrustFMat1.5m/s=About550NFP×k=261×1.3=339.3N<FMSTEP2Considerationofeffectivethrustforce・EffectivethrustforceFrmscanbeobtainedasfollows.Frms==≒103NAtthispoint,checkthatFrmsisbelowtheratedthrust.Iftheratedthrustisexceeded,reviewthemaximumspeedforoperatingpatternandacceleration/decelerationtime.(ForLT…H,thrustcharacteristicsvarydependingonambienttemperature.Seetheratedthrustcharacteristicsdiagram.)Fortheexamplepattern,theratedthrustisabout117Nattheambienttemperatureof30℃,sothevalueis103N<117N(ratedthrust)anditcanbejudgedthatcontinuousoperationispossible.FP2×ta+(FP-2×FL)2×ta+FL2×tct2612×0.3+(261-2×91)2×0.3+912×0.52.5
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