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WARNING
Powered Wheelchair Electromagnetic Interference (EMI)
Because EM energy rapidly becomes more intense as one moves closer to the transmitting antenna
(source), the EM fields from hand-held radio wave sources (transceivers) are of special concern. It is
possible to unintentionally bring high levels of EM energy very close to the powered wheelchair's
control system while using these devices. This can affect powered wheelchair movement and brak-
ing. Therefore, the warnings listed below are recommended to prevent possible interference with the
control system of the powered wheelchair.
Electromagnetic interference (EMI) from sources such as radio and TV stations, amateur radio (HAM)
transmitters, two-way radios, and cellular phones can affect powered wheelchairs and motorized
scooters. Following the warnings listed below should reduce the chance of unintended brake release
or powered wheelchair movement which could result in serious injury.
1) Do not operate hand-held transceivers (transmitters receivers), such as citizens band (CB) radios,
or turn ON personal communication devices, such as cellular phones, while the powered wheel-
chair is turned ON;
2) Be aware of nearby transmitters, such as radio or TV stations, and try to avoid coming close to
them;
3) If unintended movement or brake release occurs, turn the powered wheelchair OFF as soon as
it is safe;
4) Be aware that adding accessories or components, or modifying the powered wheelchair, may
make it more susceptible to EMI (Note: There is no easy way to evaluate their effect on the
overall immunity of the powered wheelchair); and
5) Report all incidents of unintended movement or brake release to the powered wheelchair
manufacturer, and note whether there is a source of EMI nearby.
Important Information
1) 20 volts per meter (V/m) is a generally achievable and useful immunity level against EMI (as of
May 1994) (the higher the level, the greater the protection);
2) The MCC MKIV controller for this application has an unknown immunity level.
Modification of any kind to the electronics of this wheelchair as manufactured by Invacare may
adversely affect the RFI immunity levels.
GENERAL GUIDELINES PROCEDURE 1
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