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This vehicle has an immunity level of 20 V/m which should protect it from
Electromagnetic interferences (EMI) from Radio Wave Sources. The rapid development
of electronics, especially in the area of communications, has saturated our environment
with electromagnetic (radio) waves that are emitted by television, radio and
communication signals. These EM waves are invisible,
and their strength increases as one
approaches the source. All electrical conductors act as antennas to the EM signals and, to
varying degrees, all power wheelchairs
and scooters are susceptible to electromagnetic
interference
(EMI). This interference
could result in abnormal, unintentional movement
and/or erratic control of the vehicle. The United States requires the proceeding statement
be incorporated into the user manuals for all electric powerchairs and scooters.
Powered wheelchairs and electric scooters (in this text, both will be referred to
as
powered wheelchairs) may be susceptible to electromagnetic interference (EMI),
which is
interfering electromagnetic energy emitted from sources such as radio stations, TV
stations, amateur radio (HAM) transmitters, two-way radios and cellular phones. The
interference (from radio wave sources) can cause the powered wheelchair to release its
brakes, move by itself or move in unintended directions. It can also permanently damage
the powered wheelchair's control system. The intensity of the EM energy can be
measured in volts per meter (V/m). Each powered wheelchair can resist EMI up to a
certain intensity. This is called the "immunity level." The higher the immunity level, the
greater the protection. At this time, current technology can provide at least 20 V/m of
immunity level which would provide useful protection against common sources of
radiated EMI.
Following the warnings listed below should reduce the chance of unintended
brake
release or powered wheelchair movement that could result in severe injury:
1) Do not turn on hand-held personal communication devices such as citizens
band
(CB) radios and cellular phones while the powered wheelchair is turned on.
2)
Be aware of nearby transmitters such as radio or TV stations and try to avoid
coming close to them.
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