Electromagnetic compatibility (EMC) of powered wheelchairs and scooters

Based on recent reports of powered wheelchairs exhibiting unintended movement, laboratory tests were performed at the Center for Devices and Radiological Health (CDRH) to examine the susceptibility of these devices to interference from radio and microwave transmissions. The testing confirmed that these devices are susceptible to electromagnetic interference (EMI). CDRH has developed an EMC testing protocol for powered wheelchairs and scooter over the frequency range of 26 MHz to 1 GHz [ANSI/RESNA WC/14 1990 Draft Standard for Testing of Power and Control Systems for Electric Wheelchairs]. The protocol was presented to the RESNA standards committee for possible inclusion into the voluntary RESNA Electric Wheelchair Standard, Part 14 [CDRH/FDA Proposed EMC Addition to the draft ANSI/RESNA WC/14, amended November 1993]. Here, the authors describe some of the EMI concerns for medical devices as well as test methods and results. The need to improve EMI immunity is an important issue for medical devices