Pulsed Magnetic Fields

Applicable Test Standards

International Electrotechnical Committee (IEC)

IEC 61000-4-8: Electromagnetic Compatibility (EMC) – Testing and Measurement Techniques – Power Frequency Magnetic Field Immunity Test

IEC 61000-4-9: Electromagnetic Compatibility (EMC) – Testing and Measurement Techniques – Impulse Magnetic Field Immunity Test

Brief Overview

Electronic equipment can encounter magnetic fields at power line frequencies in a variety of places. As such, it is wise to ensure that the equipment will operate reliably when exposed to these power line frequency magnetic fields. The IEC/EN 61000-4-8 standard describes how equipment should be tested for immunity to power line frequency magnetic fields.

Magnetic fields generated at power line frequencies are all around us. The electronic equipment we use is subjected to these fields in a variety of places: residential and commercial locations, industrial installations and power plants, and medium and high voltage sub-stations. The source of the magnetic fields is typically the power line current flowing in conductors, or occasionally, transformers in nearby equipment. As such, it is wise to ensure that electronic equipment will operate reliably when exposed to these power line frequency magnetic fields, namely, 50Hz or 60Hz, depending on the country. The fields may be present continuously, or for short duration, so equipment may have to be tested by being exposed to either type of field. The proximity of the equipment to the source of the magnetic disturbance will also significantly affect the equipment’s behavior within the magnetic field since the field strength is dependent on the distance from the magnetic disturbance.