23
X. ELECTROMAGNETIC INTERFERENCE (EMI/RFI)
EMI/RFI WARNINGS
Radio waves are a form of electromagnetic energy, and can cause unintended motion of electric
mobility vehicles. When electromagnetic energy adversely affects the operation of an electrical device,
that adverse effect is called “Electromagnetic Interference” or EMI, or “Radio Frequency Interference”
or RFI.
WHERE DO RADIO WAVES COME FROM?
Radio waves are emitted from the antennas of cellular phone, mobile two-way radios (such as walkie-
talkies), radio stations, TV stations, amateur radio transmitters, wireless computer links, microwave
sources, and paging transmitters. Electromagnetic energy is more intense when closer to transmitting
antennas. The greater the transmission strength is, the greater the concern to electric mobility vehicle
users.
CAN I EXPECT MY SCOOTER TO MOVE IF EMI AFFECTS IT?
It is very difficult to predict, the effects of EMI on a scooter depend on a number of factors:
• The strength of the radio waves.
• The construction of your particular scooter.
• The location (whether it is on level ground or on an incline) and direction of the scooter.
• Whether or not your scooter is in motion.
So if the unexpected incidents described below occur with your scooter, you should consider whether or
not there is a radio wave source nearby.
• Your scooter may come to a sudden stop in an uncontrolled manner.
• Your scooter may suddenly move in an uncontrolled manner.
• The brakes on your scooter may be released suddenly in an on controlled manner.
• The electronic components of control systems may be damaged for no reason at all.
Unfortunately, EMI/RFI may be difficult to recognize, because the signals from radio sources are invisible
and may be intermittent.
ARE ALL ELECTRIC MOBILITY VEHICLES SUSCEPTIBLE TO EMI?
Each make and model of electronic mobility vehicle differs in its ability to resist EMI. Each mobility
vehicle has a particular level of resistance to EMI. This resistance is measured in volts per meter (v/m).
A higher resistance level offers greater protection against EMI. In other words, an electric mobility
vehicle with a high resistance level is less likely to be affected by a strong radio source than is an electric
mobility vehicle with a low resistance level.
