Troubleshooting EMI (Part II, Susceptibility Problems)

Some simple hints . for identifying and fixing EMI troubles. This second part of our EMI Troubleshooting guidelines is devoted to investigation and cure of EMI susceptibility problems. Since, according to our former article (Ref.1) conducted tests are faster and easier to perform, we will concentrate on these and avoid more complex and expensive radiated susceptibility test set-ups. The first half of this article will address the situation where the equipment at stake is still in the plant or lab, at the end of its development phase or in an early stage of production. The second half will cover the more difficult cases where the faultly equipment is already in service, installed at some customer site.

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Troubleshooting EMI (Part I, Emission Problems)

Some simple hints . for identifying and fixing EMI troubles. This article covers the essential aspects of a domain which is seldom addressed in current EMC litterature: «What to do when an equipment – or a whole system – is failing the tests or experiencing Interference (EMI) problems ?». Whatever we are dealing with a prototype at the end of its development phase, failing one or several EMC tests, or an already installed equipment that exhibit on-site problems, we face a situation that must be solved quickly, with an equipment that cannot be deeply modified.

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EMC FILTERS: Design, Selection and Installation of Power and Signal lines filters

Our former . eight EMC articles were aimed at familiarizing unaware readers with the fundamentals of EMI/EMC, justifying the EMC norms and testing, and explaining in simple terms the five basics interference coupling mechanisms, with the essential guidelines for controlling them. The present article goes deeper into one of the simplest, most compact and economical piece of the entire EMC arsenal: the filter. With current handling ranging from tens of Amp for signal filters up to more than hundred Amps for power line filters, they exist in all sorts of size, volume and packaging. They can be optimized against Common Mode (CM) or Differential Mode (DM) interference, or both.

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Coupling From and To the Power Mains – The 5th Coupling Path

Preamble . Our former EMC articles reviewed four of the 5 principal conduction and radiation coupling mechanisms, as they affect equipment/ system susceptibility and emissions. The last ones (EMC Articles #6 and 7) were addressing the shielding of equipment boxes, from the smaller hand-held devices up to large cabinets or even entire rooms. The present article is covering the 5th, very important coupling mechanism: How the various disturbances that exist on the power mains (public AC distribution, ship or aircraft AC distribution, vehicle dc distribution… etc) can find their way from their source down to the electronic components of a system?

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Shielding of Boxes and Enclosures (Part 2)

Our former . EMC articles reviewed the principal conduction and radiation coupling mechanisms, as they affect equipment/system susceptibility, and the last one (EMC Article #5, June Issue) was addressing Shielded Cables. The present article is focusing on the shielding of equipment boxes, from the smaller hand-held devices up to large cabinets or even entire rooms.

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Shielding of Boxes and Enclosures (Part 1)

Our former . EMC articles reviewed the principal conduction and radiation coupling mechanisms, as they affect equipment/system susceptibility, and the last one (EMC Article #5, June Issue) was addressing Shielded Cables. The present article is focusing on the shielding of equipment boxes, from the smaller hand-held devices up to large cabinets or even entire rooms.

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Shielded cables: Their Role in Reducing EMI Susceptibilty and Emissions

This is the 5th article . of our ”EMC awareness” series. At this point, before addressing the coupling path, occuring from (or to) the power mains, it was in order to review a solution that is widely involved in controlling Conducted, Radiated and Crosstalk EMI situations: the use of shielded conductors. The subject is not that simple and requires some insight. This article will explain as clearly as possible for the non-specialist how a cable shield works, how much EMI reduction can be expected, and why the choice of certain cables or installation practices will result in mediocre results.

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A Review of the principal EMI Coupling Paths – The key to understanding and preventing or solving EMI problems Part 2

Radiation Paths and cable-to-cable coupling . This is the 4th article of our EMC awareness series. The former articles, after a broad overview of the EMC subject, reviewed the principal Civilian and Military Norms and test methods, insisting on the legal inforcement of these verifications in Europe, where they are turned into mandatory, « must-comply » laws. Given that source/coupling path/victim concept is the basic approach to EMC, most of the time it is the coupling path between the culprit source and the victim equipment wich is the crux of the problem, hence of its solutions. The 5 essential coupling mechanisms were listed, by which EM Interference take place. Although any equipment can be alternately the victim, or the source, of an EMI problem, we focused on EM susceptibility as being the manifestation that appears first in the designer’s or field engineer’s worries.

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A Review of the principal EMI Coupling Paths – The key to understanding and preventing or solving EMI problems Part 1

Part 1: Conduction Paths .  As briefly described in our introductory Article N°1 ( Issue #2-2015 of EE Magazine), ElectroMagnetic Interference is a Source/Coupling Paths/Victim situation, the basis for an overall understanding of EMI control in order to reach a satisfactory level of compatibility (EMC). We also said that reducing the interference at the source itself, or at the victim’s levels, were most of the time unpractical. Therefore, the only remaining area for action is in general the coupling path, which implies understanding the coupling mechanism.

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