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1、IEEETRANSACTIONSONINDUSTRYAPPLICATIONS,VOL.IA-9,NO.5,SEPTEMBER/OCTOBER1973563DutyCycleCharacteristicsforDCServoMotorsS.NOODLEMAN,SENIORMEMBER,IEEE,ANDBALUR.PATEL,MEMBER,IEEEAbstract-Thispaperdescribesmethodsofcalculatingthepeaktem-LWS[ES*VI-I0C'WATTperatureriseofthe
2、armaturewindingofadcservomotorwhenop-eratedonaspecificdutycycleandfortorquevaluesgreaterthanrated.ItalsodefinestherelationshipofthemaximumallowabletimeON(tR)foradesiredoutputtorquesuchthatthepeaktemperaturerisewillnotTETexceedthetemperatureratingoftheinsulationthuse
3、nsuringadequate--ALrtIL.TE.Dinsulationlife.Anewapproachofspecifyingthesedutycyclecharac-teristicsissuggestedwhichcanbeusedtofindthemaximumtimeON(tR)foragiventorqueaswellasthepeaktemperatureriseforanylengthoftimeON(t1).TheuseofthesecharacteristicscanbeextendedLOSSES'
4、,-27.5W:ATr--fromrepetitivecyclestodutycycleswhereoutputtorquerequirementswithinacyclearevarying.Thisanalyticalapproachissupportedbyex-perimentaldata.INTRODUCTIONTIMENMIN'FORdcservodrivemotorsusedinapplicationssuchasma-Fig.1.Armaturewindingtemperaturerisecurvesatrat
5、edcontinuouschinetoolswherehighintermittenttorquerequirementstorqueandat25-percentdutyfortypicaldcservomotorwithitsvaryindefiniterepetitivecycles,theultimatetemperaturerisethermaltimeconstantequalto57min.ofthearmaturewindingisanimportantfactordeterminingthemachineli
6、feforagivenclassofinsulation.Fromtheuser'satfixedspeedandloadconditions.Mostoftheapplicationsstandpoint,suchinformationasthearmaturetemperatureriserequirevariationsinloadandspeedandinsomesortofrepeti-whichresultsforagivenintermittenttorqueandthetimethattivecycle.The
7、armaturewinding,ofadcservomotorwithathistorquecanbemaintained,isveryvitalinselectingtherightpermanentmagnetfieldstructure,isthemajorsourceofheatkindofservodrive.Thesetemperaturerises,basedondutygenerationandthusunderthevaryingloadconditionsitstem-cycleparameters,are
8、madeontheassumptionthattheproductperaturerisemayexceeditsrating,affectingthelifeofthema-oflossesanditstimeperiodsummedupoverthetotaltimech