Karma KP12 Series, Руководство пользователя

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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 level of
intensity. This amount of resistance is called its immunity level. The higher the immunity
level is, the greater the protection will be. 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
3. Long-range transmitters and transceivers, such as commercial broadcast transmitters (radio
and TV broadcast antenna towers) and amateur (HAM) radios.