Pulse Magnetic Field Background
Pulse Magnetic Fields are produced as a result of a large current impulse through a conductor. An example is lightning current flowing through a grounding conductor at a power sub-station. Pulse magnetic fields can also occur in heavy industrial areas where very large current impulses are used in a manufacturing process.
Electronic products are tested for immunity pulse magnetic fields to insure their continued reliable operation when placed in service in a very harsh environment. Although most electrical and electronic products will not have to be tested for pulse magnetic field immunity, the European Union’s EMC Directive may mandate this testing as a condition for obtaining the CE Mark under special circumstances and for specific products before shipping to a member state of the European Union.
Although not currently required by Generic Immunity, Product specific, or Product Family Standards, future standards may require Pulse Magnetic Field tests be performed in accordance with Basic EMC Standards: IEC 61000-4-9 and EN 61000-4-9. Thermo KeyTek's Application Note, "EMC Standards Overview," provides an overview of European Standards for electromagnetic compatibility, describes how the Standards relate to one another, and lists sources for procuring copyrighted documents. 1 IEC 61000-4-9 and EN 61000-4-9 are virtually identical standards.
Basic EMC Standard
The Basic EMC Standard for Pulse Magnetic Field defines methods of generating consistently reproducible current impulses for test purposes. Field amplitudes required by these standards range from 100 - 1000 Amps per meter. Although applicable only to apparatus containing devices susceptible to magnetic fields, testing may be required to make that determination.
||IEC 61000-4-9 Level
||Field Strength A/m
|Environment where sensitive devices using electron beams can be used
|Residential, office and hospital areas far away from earth conductors of lightning protection systems
|Commercial areas, control building, field of industrial plants with lightning protection system or metallic structures nearby
|Heavy industrial and power plants and H.V. substation control rooms
|Switchyard areas of heavy industrial plants
|Higher or lower environmental levels than those described above
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