Electromagnetic Interference (Emi) - Heartway Medical Products S20 User Manual

ELECTROMAGNETIC INTERFERENCE (EMI)

The rapid development of electronics, especially in the area of communications, has saturated our
environment with electromagnetic (EM) radio waves that are emitted by television, radio and communication
signals. These EM wave are invisible and their strength increases as one approach the source. All electrical
conductors act as antennas to the EM signals and, to varying degrees, all power scooters and scooters are
susceptible to electromagnetic interference (EMI). The interference could result in abnormal, unintentional
movement and/or erratic control of the vehicle. The United States Food and drug Administration (FDA)
suggests that the following statement be incorporated to the user's manual for all power scooter like the S20.
Power scooters may as susceptible to electromagnetic interference (EMI), which is interfering electromagnetic
energy emitted from sources such as radio stations, TV stations, amateur radio (HAN) transmitter, two-way
radios, cellular phones and alarm systems of shops. The interference (from radio wave sources) can cause the
power scooter to release its brakes, move by itself or move in unintended directions. It can also permanently
damage the powered scooter's control system. The intensity of the EM energy can be measured in volts per
meter (V/m).Each powered scooter can resist EMI up to a certain intensity. This is called "immunity level". The
higher the immunity level the greater the protection. At this time, current technology is capable of providing
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
scooter movement that could result in serious injury:
Do not turn on hand-held personal communication devices such as citizens band (CB) radios and cellular
1.
phones while the powered scooter is turned on.
Be aware of nearby transmitters such as radio or TV stations and try to avoid coming close to them.
2.
If unintended movement or brake release occurs, turn the powered scooter off as soon as it is safe.
3.
Be aware that adding accessories or components, or modifying the powered scooter, may make it more
4.
susceptible to interference from radio wave sources (Note: It is difficult to evaluate the effect on the
overall immunity of the powered scooter).
Report all incidents of unintended movement or brake release to the powered scooter manufacturer, and
5.
note whether there is a radio wave source nearby.
TURN OFF YOUR POWERED SCOOTER AS SOON AS POSSIBLE WHEN EXPERIENCING THE FOLLOWING:
 Unintentional scooter movements
 Unintended or uncontrollable direction.
 Unexpected brake release
The FDA has written to the manufacturers of power scooters asking them to test new products to be sure they
provide a reasonable degree of immunity against EMI. The FDA requires that a powered scooter should have
an immunity level at least 20 V/m, which provides a reasonable degree of protection against more common
sources of EMI. The higher the immunity level the greater the protection. Your powered scooter has an
immunity level of 20 V/m which should protect against common sources of EMI. Warning: The scooter itself
can disturb the performance of the electromagnetic fields such as emitted by alarm systems of shops.
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