MAGNETIC-FIELD FLUX-DENSITY AND SPECTRAL CHARACTERISTICS OF MOTOR-DRIVEN PERSONAL APPLIANCES

Flux density and spectral measurements were carried out on magnetic fi elds generated by several types of motor-driven personal appliances us ed near the body. Among the units tested were several for which the av erage flux densities, as determined at the surfaces of the appliance, exceeded 0.4 mT. Time-rates-of-change (dB/dt) for several units exceed ed 1000 T/s, and several units exhibited high-frequency components in the low-MHz range. Use of such appliances, although normally of short duration, can represent exposure to magnetic fields of relatively high flux density, which may also have high-frequency components. Compared to other household and commercial sources of magnetic fields, those g enerated by certain motor-driven personal appliances may represent a s ignificant contribution to time-weighted average exposure and may repr esent an important source of local induced currents in the body. Furth ermore, high-frequency transients that represent only a minor contribu tion to time-weighted average exposure may generate significant instan taneous induced currents. (C) 1994 Wiley-Liss, Inc.