Magnetic field immunity testing-relevant requirement or unnecessary burden

The purpose of the European EMC Directive is to force equipment designers/manufacturers to produce robust equipment able to perform adequately in the presence of interference from electrical/magnetic phenomena. The first wave of EMC specifications written to enable compliance to be assessed ignored the very common and equally troublesome topics of magnetic susceptibility. The latest basic harmonised specifications EN 61000-4-8, EN 61000-4-9 and EN 61000-4-10 are designed to give manufacturers specifications against which they can now rate their products. These specifications emulate real world phenomena: AC mains power induced fields, power frequency magnetic field (EN 61000-4-8); lightning strike, pulse magnetic field (EN 61000-4-9); and power circuit switching transients, damped oscillatory magnetic wave (EN 61000-4-10). This paper examines some of the parameters of the magnetic phenomena experienced in the real world and compare the values to those achieved in the test methods specified