Electromagnetic Interference (Emi) - Hoveround mpv5 Owner's Manual And Warranty

Chapter 8

Electromagnetic Interference (EMI)

Our environment is saturated with radio electromagnetic (EM) waves that
originate from transmitters of television, radio and communication signals.
The waves are invisible and their strength at any location is unknown but in
general, the strength of a given EM wave increases as you move toward
the transmitting source. All electrical conductors act as antennas to the
EM signals. To varying degrees, all power wheelchairs and scooters are
susceptible to electromagnetic interference. Abnormal operation in the
form of unintentional movement and/or erratic control of the vehicle
could result if the interference is such as to override the control system of
the vehicle. The U.S. F.D.A. has suggested that the following statement be
incorporated to the owner's manual for all power wheelchairs.
Electromagnetic Interference (EMI) From Radio Wave Sources.
Power wheelchairs and motorized scooters (in this text, both will be
referred to as power wheelchairs) may be susceptible to electromagnetic
interference (EMI) which is interfering EM 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 power wheelchair to release its brakes, move by itself or move
in unintended directions. It can also permanently damage the power
wheelchair's control system. The intensity of the interfering EM energy can
be measured in volts per meter (V/m). Each power wheelchair can resist
EMI up to a certain intensity. This is called its "immunity level".
The higher the immunity level, the greater the protection. At this time, current
technology is capable of achieving at least a 20 V/m immunity level,
which would provide useful protection from the more common sources of
radiated EMI. This MPV5 power wheelchair model, as shipped, without any
further modification has a tested immunity level of at least 20 V/m. There are
a number of sources of relatively intense electromagnetic fields in
the everyday environment. Some of the sources are obvious and easy to
avoid. Others are not so obvious and exposure is unavoidable. However,
we believe that by following the warnings listed below, your risk to EMI will
be minimized.
48 Chapter 8 D82008753R 10/15