4.6.16,TeslaCarBFieldcomplex_v2.docx 1/7
ComparativeMagneticFieldlevelsTeslaModelS&HondaCRVByLawrenceGust
Feb28,2013OnFebruary20theTeslaModelSwasdriveninanormalmannerarounddowntownSeattleinacombinationofacceleration,decelerationandwaitingatrafficlights.Preliminarymeasurementsshowedthefieldswerehighestatfloorlevelanddecreasedoffwithdistancefromthefloor.Magneticfieldlevelversustimewasthencollectedduringdrivingtimebyplacingthemeteronthefloorpanandonthelapbothatthefrontpassengersideandthedriver’sside.Passengerside,frontfloorfieldsareabout20%lessthanthedriver’sside.Thelapfieldisabouttwiceasthedriver’sside.Forcomparisonpurposesdatawascollectedina2007HondaCRVfromthedriver’ssideflooranddriver’slaponlyinnormalstopandgodrivinginVentura,CA.onFebruary28,2013.Thecharacterofthefieldsishighlyvariableateverylocationinbothcarswithfrequentpulsingtohighermagneticfieldlevels.Higherfrequencycomponentswerepresentinbothcars.IntheTeslamagneticfieldcomponentslessthan2000Hzdominated.ThiswasnotthecaseintheHonda.Surprisingly,thefieldcomponentsatfrequenciesabove2000werevirtuallyabsent.Thedriver’slapaveragefieldlevelishigherintheHondacomparedtotheTeslabyafactoroftwotimes.AndthefieldspikesintheHondaarehigherthantheTeslabyafactorofthreetimes.TheTesladriver’sfloortotalaveragefieldishigherandcomparedtotheHondabyafactorofthreetimes.However,thefieldspikesintheHondafromfrequencies<2000Hzwere45%higherthantheTesla.Theactualfrequenciesfoundandtheirrelativepredominancearedifferentbetweenthetwocars.Peopledifferintheirsensitivitytofrequenciessocouldbedifferentreactiontoonecarovertheotherbasedonthis.Steelbeltedradialtirearereportedtoproducevaryingmagneticfieldsthefrequencyofwhichdependonwheelrotationrate.Nomagneticfieldsseemtobevisibleinthetracesfromeithercarthatwouldcorrespondtothistypeofslowervariation.Soyoucanseethatthereisnoclearcutwinneronecarovertheothersofarasmagneticfieldexposureisconcerned,buttheremaybedifferencesinindividualcomfortbasedonfrequencysensitivities.Additionally,onecannotforgetthatmostnewercarshaveBluetoothradiofrequency(RF)radiationthatconnectswirelessdevicestothecaraudiosystem.Thiswasnotmeasured,buttheRFradiationisquitepowerful.
