14
www.pridemobility.com
Jet12/RevC/Feb03
EMI/RFI WARNINGS
Laboratory tests performed by the Food and Drug Administration (FDA) have shown that radio waves can
cause unintended motion of electric mobility vehicles. Radio waves are a form of electromagnetic energy
(EM). When this energy unintentionally affects the operation of an electronic device, it is called
Electromagnetic Interference
(EMI)
or
Radio Frequency Interference
(RFI)
.
WARNING! Radio waves may interfere with the control of power chairs.
FREQUENTLY ASKED QUESTIONS (FAQS)
The following FAQs summarize what you should know about EMI/RFI. Use this information to minimize
the risk that EMI/RFI may affect your power chair.
Where do radio waves come from?
Radio waves are emitted from the antennas of cellular phones, mobile two-way radios, walkie-talkies,
radio stations, TV stations, amateur radio (HAM) transmitters, wireless computer links, microwave sources,
and paging transmitters. Radio waves are a form of electromagnetic energy (EM). EM is more intense
closer to transmitting antennas, which are sources of emission. The greater the transmission strength, the
greater the concern to electric mobility vehicle users.
If my power chair is affected by EMI/RFI, what kind of motion should I expect?
This is hard to predict. The effect may depend on a number of factors including:
n
Strength of the radio waves
n
Construction of the electric mobility vehicle
n
Position of the power chair (whether it is on level ground or on a slope)
n
Whether or not the electric mobility vehicle is in motion
Electric mobility vehicle motion caused by EMI/RFI can be erratic. The vehicle may move by itself or
come to a sudden stop. Furthermore, it is possible for EMI/RFI to unexpectedly release the brakes on an
electric mobility vehicle. Some intense sources of EMI/RFI can even damage the control system of an
electric mobility vehicle.
Is there any way to know for sure whether radio waves are responsible for the unintended motion
of my power chair?
Unfortunately, interference from radio wave sources may be difficult to recognize, because the signals
from these sources are invisible and may be intermittent. However, the FDA recommends that you report
all incidents of unintended motion or brake release to the electric mobility vehicle manufacturer and, if
possible, note whether there was a radio wave source nearby at the time of the incident.
Has anyone been hurt from erratic, unintended motion of electric mobility vehicles?
The FDA has reports of injuries that may have resulted from the uncontrolled motion of electric mobility
vehicles. However, it is unclear how many of these incidents were actually caused by radio wave interference.
I I I . E M I / R F I