7
V. EMI
(
ELECTROMAGNETIC INTERFERENCE
)
!
WARNING
Read all warnings to reduce the risk of unintended power
wheelchair movement:
1. Beware of the danger from hand-held transceivers. NEVER
turn on or use a hand-held transceiver while power to your
wheelchair is on. Use extra care if you believe that such a
device may be in use near your power wheelchair.
2. Be aware of nearby radio or TV stations, and avoid coming
close to them.
3. If unintended movement occurs, turn your power wheelchair
off as soon as it is safe.
WHAT IS EMI?
!
WARNING
1. EMI means: electromagnetic (EM) interference (I). EMI
comes from radio wave sources such as radio transmitters
and transceivers. (A ”transceiver” is a device that both sends
and receives radio wave signals).
2. There are a number of sources of intense EMI in your daily
environment. Some of these are obvious and easy to avoid
while others are not, and you may not be able to avoid them.
3. Powered wheelchairs may be susceptible to electromagnetic
interference (EMI) emitted from sources such as radio
stations, TV stations, amateur radio (HAM) transmitters, two
way radios, and cellular phones.
4. EMI can also be produced by conducted sources or
electrostatic discharge (ESD).
WHAT EFFECT CAN EMI HAVE?
!
WARNING
1.
EMI
can cause your power wheelchair, without warning, to:
• Move by itself
• Move in unintended directions
If any of these occurs, it could result in severe injury
to you or others.
2.
EMI
can damage the control system of your power
wheelchair. This could create a safety hazard, and lead to
costly repairs.
SOURCES OF EMI
!
WARNING
The sources of
EMI
fall into three broad types:
1. HAND-HELD TRANSCEIVERS
The antenna is usually mounted directly on the unit.
These include:
• Citizens band (CB) radios
• ”Walkie-talkies”
• Security, fi re and police radios
• Cellular phones
• Laptop computers with phone or fax
• Other personal communication devices
2. MEDIUM-RANGE MOBILE TRANSCEIVERS
NOTE
- These devices can transmit signals while they are on,
even if they are not in use.
These include two-way radios used in police cars, fi re trucks,
ambulances and taxi cabs. The antenna is usually mounted
on the outside of the vehicle.
3. LONG-RANGE TRANSCEIVERS
These include commercial radio and TV broadcast antenna
towers and amateur (HAM) radios.
NOTE
- The following are not likely to cause EMI problems:
lap top computers (without phone or fax), cordless phones,
cell phones, TV sets or AM/FM radios, CD or tape players.
DISTANCE FROM THE SOURCE
!
WARNING
EM energy rapidly becomes more intense as you get closer to the
source. For this reason, EMI from hand-held devices is of special
concern. (See
C. SOURCES OF EMI
above). A person using
one of these devices can bring high levels of EM energy very
close to your power wheelchair without you knowing it.
Summary of Contents for ALLTRACK M3 Series
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