Karma KP-25.2, Owner'S Manual

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6
3. EMI/RFI
This section provides the user with basic information about the problems with
EMI, known sources of EMI and protective measures either to reduce the
possibility of exposure or to minimize the degree of exposure. This section also
shows some conditions in which unexpected or erratic wheelchair movements
may occur.
CAUTION:
It is very important that you read this information regarding the possible effects
of electromagnetic interference on your electric KARMA wheelchair.
Electromagnetic Interference From Radio Wave Sources
Powered vehicles may be susceptible to electromagnetic interference (EMI),
which is interfering electromagnetic energy (EM) emitted from sources such as
radio stations (Radio Frequency Interference), TV stations, amateur radio (HAM)
transmitters, two-way radios, and cellular phones. The interference (from radio
wave sources) can cause the powered vehicle to release its brakes, move by
itself, or move in unintended directions. It can also permanently damage the
powered vehicle's control system. The intensity of the interfering EM energy
can be measured in volts per meter (V/m). Each powered vehicle can resist EMI
up to a certain intensity. This amount of resistance 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
powered vehicle model, with no further modification, has an immunity level of 20
V/m without any accessories.
There are a number of sources of relatively intense electromagnetic fields in our
everyday environment. Some of these sources are obvious and easy to avoid.
Others are not apparent and exposure could be unavoidable. However, we
believe that by following the warnings listed below, your risk to EMI can be
greatly minimized.
The sources of radiated EMI can be broadly classified into three types:
1. Hand-held portable transceivers (transmitter-receivers) with the antenna
mounted directly on the transmitting unit, such as citizens band (CB)
radios, walkie-talkies, security and fire or police transceivers, cellular
telephones and other personal communication devices;
NOTE:
Some cellular telephones or similar devices transmit signals while they are ON,
even though they are not in use.
2. Medium-range mobile transceivers used in police cars, fire trucks,
ambulances and taxis usually having the antenna mounted on the outside
of the vehicle; and