Magnetic-field flux density and spectral characteristics of motor-driven personal appliances.
Flux density and spectral measurements were carried out on magnetic fields generated by several types of motor-driven personal appliances used near the body. Among the units tested were several for which the average flux densities, as determined at the surfaces of the appliance, exceeded 0.4 mT. Time-rates-of-change (dB/dt) for several units exceeded 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 generated by certain motor-driven personal appliances may represent a significant contribution to time-weighted average exposure and may represent an important source of local induced currents in the body. Furthermore, high-frequency transients that represent only a minor contribution to time-weighted average exposure may generate significant instantaneous induced currents.
Wilson
B W
BW
Pacific Northwest Laboratory, Richland, Washington 99352.
Hansen
N H
NH
Davis
K C
KC
D002138:Calibration; D017097:Electric Impedance; D004560:Electricity; D004574:Electromagnetic Fields; D004781:Environmental Exposure; D005123:Eye / Q000528:radiation effects; D006257:Head / Q000528:radiation effects; D006794:Household Articles; D006801:Humans; D008280:Magnetics / Q000145:classification*; D013499:Surface Properties; D013997:Time Factors