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- Good grounding practices - Part 2
- Grounding and Shielding of Electronic Systems
- Grounding & Shielding 2.1 Grounding Generalities
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If you don't have a login, click here to register Forgot your password? The coexistence of equipment of different technologies and the inadequacy of the installations favors the emission of electro-magnetic energy and often causes problems of electro-magnetic compatibility.
Good grounding practices - Part 2
Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Safety, system protection and performance are the three main reasons to earth a system. Not all electronic equipment needs to be connected to earth to work, satellites are an example. Sometimes wrong grounding configurations, oriented to satisfy the special power and performance requirements of electronic loading equipment, can compromise safety rules generating dangerous situations for personnel and equipment. Save to Library.
There are different types of grounding; single point grounding whereby multiple pieces of equipment are connected to one ground connection — in series or parallel — and multi-point grounding whereby each piece of equipment has its own ground connection. The shielding performance of a cable is indicated by its transfer impedance Zt. The lower the transfer impedance value the better the shielding performance. Transfer impedance can be drastically increased by incorrect shield termination. The question that often comes up is whether both ends or only one end of a shielded cable should be terminated.
It is important to understand the mechanism that causes grounding noise in order to effectively eliminate it Stoorsignalen en aarding in Dutch, pdf file Understanding Common-Mode Signals Understanding Common-Mode Signals. The following discussion defines a common-mode signal, reviews the common cable configurations, considers shielded vs. The educational encyclopedia. Electricity High Voltage. Utilities - tools.
Grounding and Shielding of Electronic Systems
Well designed electronic systems operate reliably in their intended electromagnetic environment. In a well designed system, the cost of grounding, shielding and filtering is usually a negligible percentage of the overall system component costs. Unfortunately, many electronic systems are not well designed. It is not unusual for a company to spend millions of dollars and thousands of man-hours attempting to track down and correct system malfunctions that are the direct result of improper grounding and shielding. This course reviews the fundamental grounding, filtering and shielding concepts that all engineers need to be familiar with in order to ensure the safety and reliability of their products at the lowest possible cost. Todd H.
In an electrical system, a ground loop or earth loop occurs when two points of a circuit are intended to have the same ground reference potential but instead have a different potential between them. Ground loops are a major cause of noise , hum, and interference in audio, video, and computer systems. Wiring practices that protect against ground loops include ensuring that all vulnerable signal circuits are referenced to one point as ground. The use of differential connections can provide rejections of ground-induced interference. Removal of safety ground connections to equipment in an effort to eliminate ground loops also eliminates the protection the safety ground connection is intended to provide. A ground loop is caused by the interconnection of electrical equipment that results in there being multiple paths to ground, so a closed conductive loop is formed.
system. Not all electronic equipment needs to be connected to earth to work, The grounding of power systems is, from a safety standpoint, oriented to limit the.
Grounding & Shielding 2.1 Grounding Generalities
The document describes an optimized structure for process automation systems intended to reduce the effects of electromagnetic interference EMI and disturbances by using equipotential bonding systems. In a tiered approach, the readers are first made familiar with the technical basics of electromagnetic compatibility EMC , equipotential bonding and shielding. In chapter 4, six recommendations for action are developed by using a plant example. This document has no normative character. It may be useful in certain operating environments, in certain technical constellations or when used in certain countries to deviate from the given recommendations.
Skip to Main Content. A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. Use of this web site signifies your agreement to the terms and conditions. Grounding, bonding, shielding, and isolation of electronic signals Abstract: All input power systems must be grounded for protection of personnel, property, and to insure the proper performance of the electrical system.
Our website is packed full of both free and paid-for content, including:. Our aim is to help people learn how to more quickly and cost-effectively design and manufacture electronic equipment products, systems, installations, etc. Such equipment should benefit from reduced warranty costs and financial risks, whilst improving uptime, competitiveness and profitability. Find your EMC Standards quickly and easily
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Few topics generate as much controversy and argument as that of grounding and the associated topics of surge protection, shielding and lightning protection of electrical and electronic systems. Poor grounding practice can be the cause of continual and intermittent difficult-to-diagnose problems in a facility. This book looks at these issues from a fresh yet practical perspective and enables you to reduce expensive downtime on your plant and equipment to a minimum by correct application of these principles. Malcom Barnes is a professional engineer with over thirty-five years' experience specialising in automation, switchgear and process control equipment. Malcom has presented numerous courses in automation and variable speed drives throughout the world. Also, it covers not only low voltage grounding techniques but also power system grounding, which is generally not well covered in literature
Post a Comment. Practical Grounding, Bonding, Shielding and Surge Protection is a practical engineer's guide to the areas of grounding, shielding and surge protection designed to deliver reliable equipment and communications systems that comply with international and national codes. Practical Grounding, Bonding, Shielding and Surge Protection unlike many books on grounding and shielding, provides straight-forward, practical solutions to commonly encountered real-world situations and enables one to better understand proper ground methods and to quickly recognize and solve existing grounding issues in a facility.
Electromagnetic Compatibility Handbook pp Cite as. Chapter 5 presents a number of considerations regarding grounding in discussing the broader subject of intrasystem EMI prediction and control. The main consideration is to avoid the creation of low-impedance ground loops associated with resulting common-mode EMI. For the control of EMI, wiring, circuits, printed circuit boards, equipment racks, and so on, in some instances should not be grounded i. Circuit designs and layouts should consider maintaining high ground-loop impedances to minimize circulating common-mode currents that may flow into circuits containing sensitive victim loads. Floating is often especially effective at low frequencies.
When asked to quantify what such a ground is, they generally talk about a ground not connected to that dirty, nasty power ground. It seems they expect that noise or problems will somehow arise out of the ground and strike down their equipment. This is basically a question of whether to have a separate, isolated hence somehow clean , instrument ground, or to have it a part of the overall facility grounding grid. A perfect ground would never vary in potential—zero potential anywhere potential because it is single-ended, unlike voltage, which is double-ended, or a potential in reference to another potential. This theoretical ground would also have zero impedance—current flowing to ground would encounter no resistance, and anything connected would always be at the same ground potential.
Неплохо, но есть одно. Он не пользовался своими обычными почтовыми ящиками - ни домашним, ни служебными. Он бывал в Университете Досися и использовал их главный компьютер. Очевидно, там у него был адрес, который он сумел утаить. Это хорошо защищенный почтовый ящик, и мне лишь случайно удалось на него наткнуться. - Он выдержал паузу. - Итак, если Танкадо хотел, чтобы мы обнаружили его почту, зачем ему понадобился секретный адрес.
Я чувствую. Она знала, что есть только один способ доказать свою правоту - выяснить все самой, а если понадобится, то с помощью Джаббы. Мидж развернулась и направилась к двери. Откуда ни возьмись появился Бринкерхофф и преградил ей дорогу. - Куда держишь путь. - Домой! - солгала Мидж.
Беккер обернулся. Двери оказались прямо перед ним, словно приглашая его принять участие в празднестве, до которого ему не было никакого дела. Внезапно он понял, что входит в собор.
Это диагностика, - сказала она, взяв на вооружение версию коммандера. Хейл остановился: - Диагностика? - В голосе его слышалось недоверие. - Ты тратишь на это субботу, вместо того чтобы развлекаться с профессором. - Его зовут Дэвид. - Какая разница?.
С каких это пор заместитель директора начал действовать в обход фильтров. Сотрудникам лаборатории платили хорошие деньги, чтобы они охраняли компьютерные системы АНБ, и Чатрукьян давно понял, что от него требуются две вещи: высочайший профессионализм и подозрительность, граничащая с паранойей. Черт возьми! - снова мысленно выругался. - Никакая это не паранойя. Этот чертов компьютер бьется над чем-то уже восемнадцать часов.
Стратмор отпустил створки двери, и тонюсенькая полоска света исчезла. Сьюзан смотрела, как фигура Стратмора растворяется во тьме шифровалки. ГЛАВА 63 Новообретенная веспа Дэвида Беккера преодолевала последние метры до Aeropuerto de Sevilla.
Сьюзан, - сказал он торжественно. - Здесь мы в безопасности. Нам нужно поговорить.