Electromagnetic interference (EMI) from radio wave sources
It is very important that you read this information regarding the possible effects of electromagnetic inter- ference on your Everest & Jennings® Everest with Captain Seat power wheelchair.
Powered wheelchairs may be susceptible to electromagnetic interference (EMI), which is interfering electromagnetic (EM) energy emitted from sources such as radio stations, TV stations, amateur radio (HAM) transmitters, two-way radios, and cellular telephones. The interference (from radio wave sources) can cause the powered wheelchair to release its brakes, move by itself, or move in unintended directions. It can also permanently damage the powered wheelchair's control system. The intensity of the interfering EM energy can be measured in volts per meter (V/m). Each powered wheelchair can resist EMI up to a certain intensity. This is called its “immunity level”. The higher the immunity level, the greater the pro- tection. 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 wheelchair model has an immunity level of 20 V/m.
Be aware that using different components, adding accessories, or modifying the powered wheelchair may change the immunity level.
There are a number of sources of relatively intense electromagnetic fields in the everyday environment. Some of these sources are obvious and easy to avoid. Others are not apparent and exposure is unavoid- able. However, we believe that by following the warnings that follow, your risk to EMI exposure will be minimized.
The sources of radiated EMI can be broadly classified into three types:
1)Hand-held portable transceivers (transmitters-receivers) with the antenna mounted directly on the transmitting unit. Examples include: citizens band (CB) radios, “walkie talkies”, security, fire, and police transceivers, cellular telephones, and other personal communication devices.
Note: Some cellular telephones and similar devices transmit signals while they are on, even when not being used;
2)Medium-range mobile transceivers, such as those used in police cars, fire trucks, ambulances, and taxis. These usually have 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.
Note: Other types of hand-held devices, such as cordless telephones, laptop computers, AM/FM radios, TV sets, CD players, and cassette players, and small appliances, such as electric shavers and hair dryers, so far as we know, are not likely to cause EMI problems with your powered wheelchair.
Powered Wheelchair Electromagnetic Interference (EMI)
Because EM energy rapidly becomes more intense as one moves closer to the transmitting antenna (source), the EM fields from hand-held radio wave sources (transceivers) are of special concern. It is pos- sible to unintentionally bring high levels of EM energy very close to the powered wheelchair's control system while using these devices. This can affect powered wheelchair movement and braking. Therefore, the warnings that follow are recommended to prevent possible interference with the control system of the powered wheelchair.
