Pride Mobility Jazzy 1113 - Manual (Page 14)

14 www.pridemobility.com US Jazzy 1113/Rev I/Feb03
I I I . E M I / R F I
EMI/RFI—FREQUENTLY ASKED QUESTIONS (FAQS)
The following FAQs summarize what you should know about EMI/RFI. Use this information to minimize the risk
that EMI/RFI will affect your power chair.
WARNING! Radio waves may interfere with the control of power chairs.
Where do radio waves come from?
Radio waves are emitted from the antennas of cellular phones, mobile two-way radios (such as walkie-talkies),
radio stations, TV stations, amateur radio (HAM) transmitters, wireless computer links, microwave sources, and
paging transmitters. Radio waves are a form of electromagnetic energy. Because EM is more intense closer to the
transmitting antenna (source of emission), the EM fields from two-way radios are of special concern to power
chair users.
Are all power chairs susceptible to EMI?
Each make and model of chair differs in its ability to resist electromagnetic interference. That is, each has a
particular level of “immunity” to interference, measured in volts per meter (V/m). A higher immunity level offers
greater protection. In other words, a power chair with a high immunity level is less likely to be affected by a strong
radio source than one with a low immunity level.
What is the FDA doing about the problem?
The FDA has written to the power chair manufacturers and requested that they test their new products to be sure that
they provide a reasonable degree of immunity against EMI. The letter states that power chairs should have an immunity
of at least 20 V/m. This provides a reasonable degree of protection against the common sources of EMI/RFI.
The FDA has also requested that these manufacturers clearly label their products with the immunity level, or state
that the immunity level is not known. The labeling and informational material supplied with the power chair must
explain what the immunity level means, and the labeling or informational material must warn users about the possibility
of EMI/RFI and how to avoid it. In addition, the FDA has recommended that manufacturers establish an educational
program to inform power chair users and their caregivers about the problems associated with EMI/RFI, and the
actions they can take to minimize the risk.
If my power chair is affected by EMI/RFI, what kind of motion should I expect?
This is hard to predict. It depends on a number of factors:
n Strength of the radio waves
n Construction of the power chair
n Position of the power chair (whether it is on level ground or on an incline)
n Whether or not the power chair is in motion
An affected power chair’s movement can be erratic. It may move by itself or come to a sudden stop. Furthermore,
it is possible for EMI/RFI to unexpectedly release the brakes on a power chair. Some intense sources of EMI/RFI
can even damage the control system of your Jazzy.