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Agilent AN 1319 Compliance Testing to IEC/EN 61000-4-8 Application Note Compliance Testing to the IEC/EN 61000-4-8 Standard "The magnetic fields to which equipment is subjected may influence the reli- able operation of equipment and systems." The statement above is taken directly from the IEC/EN 61000-4-8 standard, and is the premise upon which the standard is based. 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. This application note provides a discussion of the standard, including interpretation of the requirements, and suggestions for equipment selection. Table of Contents 2 Introduction 3 Selecting a test level 5 Generating a test field 5 The induction coil 8 The test generator 13 Current measurement 14 Transformers 16 Performing a test 17 Evaluating test results 18 Appendix 18 References Agilent Technologies Introduction Magnetic fields generated at power which electronic equipment is sub- short duration if a protection device line frequencies are all around us. jected to ensure the equipment con- like a fuse, circuit breaker, or other The electronic equipment we use is tinues to operate reliably. Stated protection circuitry interrupts the subjected to these fields in a variety another way, it ensures that electronic flow. High current can also temporar- of places: residential and commercial equipment is immune to certain com- ily exist during initial power turn-on locations, industrial installations and monly occurring magnetic fields, of some electronic equipment. A com- power plants, and medium and high fields that the equipment is likely to paratively high magnetic field will voltage sub-stations. The source of encounter during operation. The spe- result while the current is flowing, the magnetic fields is typically the cific fields are those occurring at the but again, for only a short duration. power line current flowing in conduc- power line frequencies. Although The standard addresses both types of tors, or occasionally, transformers in immunity limits are not specified in fields (continuous and short dura- nearby equipment. As such, it is wise this standard, generic immunity stan- tion) by specifying field strengths for to ensure that electronic equipment dards or product standards state spe- continuously applied fields and even will operate reliably when exposed to cific limits. The standard also does higher