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1、JuniormaintenanceelectricianQ&A（维修电工初级问答）1.whyisthelowvoltagewindingofthetransformerinitandthehighvoltagewindingoutside?Answer:thearrangementofhighandlowvoltagewindingsoftransformersisdeterminedbymanyfactors.Butformosttransformers,thelowvoltagewindingisarrangedi
2、nsidethehighvoltagewinding.Thisismainlyconcernedwithinsulation.Theoretically,nomatterhowhighvoltagewindingorlowvoltagewindingisarranged,itcanchangepressure.Butbecausethecoreofthetransformerisgrounded,thelowvoltagewindingisclosetothecore,soitiseasytodofromtheinsu
3、lationangle.Ifthehighvoltagewindingclosetothecore,thehighvoltagewindingvoltage,tomeettheinsulationrequirements,itrequiresalotofinsulationmaterialsandalargerinsulationdistance.Inthisway,notonlythevolumeofthewindingisincreased,butalsotheinsulationmaterialiswasted.
4、Dailyelectriccommunity,http://www.electric365.cnInaddition,becausethevoltageadjustmentofthetransformerisrealizedbychangingthetapofthehigh-voltagewinding,namelychangingthenumberofturns,thehigh-voltagewindingisarrangedoutsidethelow-voltagewindingandtheleadiseasy.2
5、.,three-phaseasynchronousmotorishowtoturnup?Answer:whenthethree-phasealternatingcurrentthroughthethree-phasestatorwinding,willproducearotatingmagneticconstantrotationbeforethestationaryrotorconductorinarotatingmagneticfieldinthestatorcavity,theequivalentoftherot
6、orrelativetotheconductorcuttingmagneticfieldlines,resultingintheinductioncurrentintherotorconductor(electromagneticinductionprinciple).Theseinduction-induceddeadconductorsmoveinthefield(theeffectofelectriccurrent-electromagneticforce).Sincetheinnerconductorofthe
7、rotorisalwayssymmetricallyarranged,theelectromagneticforceproducedbytheconductorisjustopposite,thusformingtheelectromagnetictorqueandcausingtherotortorotate.Becausethecurrentintherotorconductorisinducedbythemagneticfieldofthestatorrotation,itisalsocalledaninduct
8、ionmotor.Alsobecausetherotorspeedisalwayslowerthantherotatingspeedofthestatormagneticfield,soitisalsocalledasynchronousmotor.3.whycan'ttransformerchangeDCvoltage?Answ
