Invacare TDXSP2 - 3 Electromagnetic Compatibility (EMC) Information; Electromagnetic Interference (EMI) from Radio Frequency Sources; Powered Wheelchair Electromagnetic Interference; (Emi)

ElectromagneticCompatibility(EMC)Information
3ElectromagneticCompatibility(EMC)
Information
3.1ElectromagneticInterference(EMI)From
RadioFrequencySources
Poweredwheelchairsandmotorizedscooters(inthistext,
bothwillbereferredtoasmobilitydevices)maybe
susceptibletoelectromagneticinterference(EMI),which
isinterferingelectromagneticenergy(EM)emittedfrom
sourcessuchasradiostations,TVstations,amateurradio
(HAM)transmitters,twowayradios,andcellularphones.
Theinterference(fromradiowavesources)cancausethe
mobilitydevicestoreleaseitsbrakes,movebyitself,or
moveinunintendeddirections.Itcanalsopermanently
damagethemobilitydevicescontrolsystem.Theintensity
oftheinterferingEMenergycanbemeasuredinvoltsper
meter(V/m).EachpoweredmobilitydevicecanresistEMI
uptoacertainintensity.Thisiscalledits"immunitylevel."
Thehighertheimmunitylevel,thegreatertheprotection.
Atthistime,currenttechnologyiscapableofachievingat
leasta20V/mimmunitylevel,whichwouldprovideuseful
protectionfromthemorecommonsourcesofradiatedEMI.
Thereareanumberofsourcesofrelativelyintense
electromagneticeldsintheeverydayenvironment.Some
ofthesesourcesareobviousandeasytoavoid.Othersare
notapparentandexposureisunavoidable.However,we
believethatbyfollowingthewarningslistedbelow,your
risktoEMIwillbeminimized.
ThesourcesofradiatedEMIcanbebroadlyclassiedinto
threetypes:
1.Hand-heldPortabletransceivers(transmitters/receivers
withtheantennamounteddirectlyonthetransmitting
unit.Examplesinclude:citizensband(CB)radios,
“walkietalkie”,security,reandpolicetransceivers,
cellulartelephones,andotherpersonalcommunication
devices).
Somecellulartelephonesandsimilardevices
transmitsignalswhiletheyareON,evenwhen
notbeingused.
2.Medium-rangemobiletransceivers,suchasthoseused
inpolicecars,retrucks,ambulancesandtaxis.These
usuallyhavetheantennamountedontheoutsideof
thevehicle.
3.Long-rangetransmittersandtransceivers,suchas
commercialbroadcasttransmitters(radioandTV
broadcastantennatowers)andamateur(HAM)radios.
Othertypesofhandhelddevices,suchascordless
phones,laptopcomputers,AM/FMradios,TVsets,
CDplayers,cassetteplayers,andsmallappliances,
suchaselectricshaversandhairdryers,sofaraswe
know,arenotlikelytocauseEMIproblemstoyour
poweredmobilitydevice.
3.2PoweredWheelchairElectromagnetic
Interference(EMI)
BecauseEMenergyrapidlybecomesmoreintenseasone
movesclosertothetransmittingantenna(source),theEM
eldsfromhandheldradiowavesources(transceivers)are
ofspecialconcern.Itispossibletounintentionallybring
highlevelsofEMenergyveryclosetothemobilitydevices
controlsystemwhileusingthesedevices.Thiscanaffectthe
60101831-A
27