Introduction to the working principles and uses of several vibration sensors
Therearevarioustypesofvibrationsensors.Accordingtodifferentworkingprinciples,theycanbedividedintoeddycurrentvibrationsensors,inductivevibrationsensors,capacitivevibrationsensors,piezoelectricvibrationsensors,andresistancestrainvibrationsensors.Thefollowingaretheworkingprinciplesandusesofthesetypesofvibrationsensors. Workingprinciplesandusesofseveralvibrationsensors 1.Eddycurrentvibrationsensor Eddycurrenttypevibrationsensorisavibrationtypesensorwhoseworkingprincipleiseddycurrenteffect.Itbelongstonon-contacttypesensor.Theeddycurrentvibrationsensormeasuresthevibrationparametersofanobjectbychangingthedistancebetweentheendofthesensorandthemeasuredobject.Eddycurrentvibrationsensorsaremainlyusedformeasuringvibrationdisplacement. 2.Inductivevibrationsensor Inductivevibrationsensorisavibrationsensordesignedaccordingtotheprincipleofelectromagneticinduction.Theinductivevibrationsensorisprovidedwithamagnetandaguidemagnet.Whenanobjectissubjectedtovibrationmeasurement,itcanconvertmechanicalvibrationparametersintoelectricalparametersignals.Inductivevibrationsensorscanbeusedtomeasurevibrationspeed,accelerationandotherparameters. Workingprinciplesandusesofseveralvibrationsensors 3.Capacitivevibrationsensor Capacitivevibrationsensorsobtainvariablecapacitancebychangingthegaporthecommonarea,andthenmeasuringthecapacitancetoobtainthemechanicalvibrationparameters.Capacitivevibrationsensorscanbedividedintotwotypes:variablegaptypeandvariablecommonareatype.Theformercanbeusedtomeasurelinearvibrationdisplacement,andthelattercanbeusedtomeasureangulardisplacementoftorsionalvibration. 4.Piezoelectricvibrationsensor Thepiezoelectricvibrationsensorusesthepiezoelectriceffectofthecrystaltocompletethevibrationmeasurement.Whenthevibrationofthemeasuredobjectputspressureonthepiezoelectricvibrationsensor,thecrystalelementwillgenerateacorrespondingcharge,andthenumberofchargescanbeconvertedintovibration.parameter.Piezoelectricvibrationsensorscanalsobedividedintopiezoelectricaccelerationsensors,piezoelectricforcesensors,andimpedanceheads. 5,resistancestraintypevibrationsensor Theresistancestrainvibrationsensorisavibrationsensorthatexpressesthemechanicalvibrationofthemeasuredobjectbythechangeofresistance.Therearemanywaystoimplementresistancestraintypevibrationsensors,andvarioussensingelementscanbeapplied,themostcommonofwhichisresistancestrain.
How to select a vibration sensor?
1.Sensorclassification; 2.Commontypesofaccelerometers; 3.Selectionindex; 4.Selectionprinciple. Sensorclassification Twocategoriesaremainlyintroducedhere,oneisactiveandpassive,andtheotherisisolatedandnon-isolated. Activesensorsrefertosensorsthatconvertnon-electricalenergyintoelectricalenergyoutput,whichonlyconvertstheenergyitself,anddoesnotconverttheenergysignal.Itisalsoknownasanenergy-convertingsensorortransducer.Therefore,thistypeofsensorrequiresexternalenergysourceexcitation,suchasexcitationvoltage,toworkproperly.Duetotheneedforenergyconversion,electroniccomponentsarepackagedinsidethesensor,whichwillbringnoiseduringthemeasurementprocess.SuchsensorsareICPtype(alsoknownasIEPEtype)accelerationsensor,zerofrequencyaccelerationsensorandsoon. Passivesensorsaresensorsthatcanworknormallywithouttheneedforanexternalpowersource,andcanobtainunlimitedenergyfromtheoutside.Thistypeofsensorhasnoorminimalimpactonthemeasurementsystem,suchasstraingauges(flowers),piezoelectricsensors,andsoon. Isolationsensorreferstotheisolationbetweenthesensorandthestructureundertest,andcurrentcannotflowbetweenthetwo.Isolationsensorsareelectricallyseparatedfromthestructureundertest.Forexample,straingauges(flowers)areusuallyisolatedfromthestructureundertest.Thecommonpracticeforsensorstoachieveisolationistoinstallanisolationdeviceatthebottomofthesensorsothatcurrentcannotflow.AsshowninFigure1,thereddeviceistheisolationdevice.
