A tri-axis electromagnetic field meter (overhead power line field measurement)

The authors describe a portable instrument which measures AC electromagnetic fields using thee detection coils and analog computation circuits. The instrument has an accuracy of 0.5% for frequencies up to 3 kHz. Three measurement methods have been incorporated in the meter: wideband RMS (root mean square), wideband average, and 60-Hz average. The meter achieved faster and more accurate results than conventional single-coil instruments, since its design eliminates the time-consuming detector orientation requirements of those instruments. The results of a measurement program at an elementary school located at the edge of a high-voltage transmission line right of way are discussed.<>