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Information on electromagnetic interference - EMI
Studies of electromagnetic interference (EMI) have shown that it adversely affects the
operation and control of electrically powered mobile devices.
EMI can come from a variety of sources, such as cell phones, two-way radios, radio
stations, TV stations, amateur radio (HAM) transmitters, wireless computer links, micro-
wave signals, paging transmitters and transmitters used by emergency vehicles. EMI
waves can cause unintended movement of the wheelchair or damage to the controller.
Every electrically powered mobile device has a certain immunity to electromagnetic
interference. The higher the immunity level, the greater the protection. The intensity
of interference can be measured in volts per meter (V/m). Current technology allows
for an immunity level of 20 V/m, which provides protection against the most common
sources of electromagnetic interference. The wheelchair, without any modifications,
has an immunity level of 20 V/m. As you get closer to the source, electromagnetic inter-
ference becomes more intense. Special attention should be paid to electromagnetic
interference from hand-held radio devices. It is possible to unintentionally bring high
levels of EMI close to the wheelchair control system, which can affect movement and
braking. To prevent possible interference with the wheelchair control system, follow
the warnings below.
WARNING!
Do not use hand-held radio transmitters such a CB-radio or cell phone near
a powered-up wheelchair.
Warning!
Drive the electric wheelchair in a straight line up or down the slope, never
reverse. Irregular forward and backward movements with changes in slope
can increase the risk of the wheelchair rollover.
WARNING!
Pay attention and stay away from nearby transmitters, such as radio or
TV stations.
