Showing papers on "Electromagnetic compatibility published in 1987"

An Introduction to Electromagnetic Compatibility

Abstract: Electrical, electromechanical, and electronic equipment all must comply with specifications intended to assure electromagnetic compatibility (EMC), which is the ability of systems, subsystems, circuits, and components to function as designed, without malfunction or unacceptable degradation of performance due to electromagnetic interference (EMI), within their intended operational environment. Essentially, any equipment or system should not adversely affect the operation of any other equipment or system as a result of radiated or conducted EMI, and, in turn, it should not be affected by same. This chapter defines EMI and EMC, discusses use of the electromagnetic frequency spectrum, describes basic elements of all EMI situations, and introduces the concepts of intersystem and intrasystem interference.

Electromagnetic Compatibility Handbook

Abstract: Basic Concepts: Definition of EMI and EMC, Classification of EMI/EMC, Sources Kenneth L. Kaiser, Electromagnetic Compatibility Handbook, CRC Press, 1st. The founders of Washington Laboratories, wrote “The Electromagnetic Compatibility Handbook” that is still a trusted reference source. Learn more. Electromagnetic Interference Electromagnetic Compatibility (EMI-EMC ) testing of cybersecurity intelligence THE SHIELDED ENCLOSURE HANDBOOK.

Transient Electromagnetic Fields Due to Switching Operations in Electric Power Systems

Abstract: Transient electromagnetic fields are produced when breakers, disconnectors, and switches of various types are operated under varying load conditions. For analysis purposes, a discharge current pulse is assumed during switching operations, which can act as a dipole antenna. The transient electromagnetic fields of this antenna can be calculated for near-and far-field conditions.

Aircraft Electromagnetic Compatibility.

Abstract: Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.

UHF-VHF Radiation from Lightning

Abstract: This article reviews the current knowledge on the very high frequency electromagnetic radiation of lightning. A phenomenology analysis of the new results obtained from the study of natural and triggered lightning in New Mexico (TRIP 82), at St. Privat d'Allier in Haute-Loire, France (1983), and in 1984 in South West France (Front 84) is first described. The authors then present the spectral and temporal characteristics of the VHF-UHF radiation which can be applied to the electromagnetic compatibility of systems. From a synthesis of the experimental and theoretical contributions, they propose a hypothesis on the lightning initiation process and on the mechanisms generating lightning radiation.

D-C commutator motor with means for interference suppression

Abstract: In order to improve the interference suppression of an electric-motor auxiliary motor-vehicle drive, particularly in the direction of electromagnetic compatibility (EMV), a protective circuit branch (2, 3) with two Zener diodes (D1; D2) or with one varistor (V1) is provided parallel to the armature circuit branch (1) of the commutator motor (M), where, for reducing the number of external solder joints, the Zener-diodes (D1; D2) or the varistor (V1) are combined with the interference suppression capacitors (C1; C2) in common integration component (6) which has only three external terminals.

Coupling between electromagnetic fields and wires using transmission-line modelling

Abstract: The paper is concerned with the interference caused by the incidence of electromagnetic waves on interconnecting wires or cable harnesses in a shielded enclosure. In particular it describes three ways of using transmission-line modelling (TLM) for calculating the coupling of electromagnetic fields with wires. It also shows how TLM can be used to solve the propagation of energy along the wires to obtain the voltages and currents on the pins of electronic devices.

Introduction of chopper controlled trains on established DC railways

Abstract: The studies that should be undertaken before introducing chopper controlled trains on established DC railways are discussed. These include the effects of the new type of load on the DC power supply and signalling, telecommunications and radio interference.

Computing transient electromagnetic fields radiated from lightning

Abstract: The effect of lightning on airborne electronic equipment and powerlines can be severe and a study requires the solution of electromagnetic fields radiated by the lightning flash. We model the return stroke by simple dipolelike line elements with resident charges prior to the return stroke. The resulting computations are from simple closed‐form expressions and permit the modeling of branched lightning. For the first time, computations bear out the observed bipolar electric fields very near the flash.

Electromagnetic Pulse Penetration into Reinforced-Concrete Buildings

Abstract: The purpose of this study is to define the protection against electromagnetic pulses (EMP's) provided by reinforced-concrete buildings. We want to define the electromagnetic field inside a building modeled by parallel wires because attenuation due to concrete itself can generally be neglected. The problem resolution is achieved by using integral equations in the time domain. These equations are solved numerically by applying the method of moments associated with the utilization of Lagrange interpolation polynomials. Applications in the field of building protection are shown.

Description of an Aircraft Lightning And Simulated Nuclear Electromagnetic Pulse (NEMP) Threat Based on Experimental Data

Abstract: Most modern aircraft are designed to withstand a direct lightning strike. To accomplish this protection, the aircraft must have an external conductive path with a given skin thickness and a minimum amount of exposed areas and antennas that could allow energy coupling to the inside. Additionally, some modern military aircraft are also designed to operate in a nuclear electromagnetic pulse (NEMP) environment. This paper provides experimental lightning data and NEMP scalemodel data to characterize both phenomena. The lightning data were obtained by measuring the surface electromagnetic fields on a CV-580 research aircraft during an actual lightning strike. The aircraft was struck by lightning 48 times in central Florida between 1500- and 18 000-ft altitude during the summers of 1984 and 1985. One of these lightning events, for which an extensive set of data was available, has been analyzed. For this event, the maximum measured values were as follows: time rate of change of the surface magnetic flux density, 3750 T/s; total normal current density, 20 A/m2; peak current, 4.7 kA; and rate of rise of the current, 38 kA/ps. The NEMP data were obtained by measuring the surface electromagnetic fields during a simulated NEMP test in a 1:74 scale model of the same aircraft. During scale-model NEMP simulation, the maximum values measured were as follows: time rate of change of the surface magnetic flux density, 40 000 T/s; and total normal current density, 90 A/m2. The analyses of these results should provide new insights for combined lightning and NEMP protection.

The Electromagnetic Environment of an Automobile Electronic System

Abstract: The objective of this paper is to report measured results of electric fields investigated inside the automobile. This investigation is important to the electronic design engineer before he starts the design of the different electronic systems needed to operate the automobile. By knowing the electromagnetic environment inside the automobile, the electronic engineer is given the opportunity to estimate and predict the various effects of electromagnetic disturbances on the automotive electronic systems. In our experiments, the work performed to study the electromagnetic environmental conditions was carried out on a typical midsize automobile with a high-power frequency-modulation (FM) transmitter installed inside the vehicle. Different antenna locations were used to radiate the electromagnetic waves that were studied. Data obtained from the experimental results are presented and discussed.

Electromagnetic environment engineering--a solution to the emi pandemic

Abstract: There are severe electromagnetic interference (EMI) problems which are pandemic throughout the fleet with both known and unknown impact on the operational performance of ships. This paper suggests that the key solution to the EMI pandemic is to develop an engineering discipline in electromagnetics (EM) comparable to the stature of naval architecture and marine engineering, to embed EM design considerations and tradeoffs throughout the ship and equipment design processes.

Statistical EMC: A New Dimension in Electromagnetic Compatibility of Digital Electronic Systems

Abstract: Statistical analysis provides a new perspective on electromagnetic compatibility (EMC) of digital electronic systems and leads to important practical results. In the paper, the electromagnetic compatibility compliance test results are used as a data base to address three classes of EMC related problems: statistical EMC profile of digital electronic systems, the equipment under test (EUT) parameter effects on the electromagnetic emission characteristics, and EMC measurement specifics. A comparison is made and statistical correlation factor concept is introduced of the EUT highest radiated emissions measured in an open area test site (OATS) and absorber lined shielded room (AR). The suggested statistical evaluation methodology can be utilized to correlate different EMC test techniques, characterize the EMC performance of electronic systems and components, and develop recommendations for electronic product optimal EMC design.

Network analyser for indicating, analysing, recording, storing and indicating electromagnetic faults

Abstract: The detection of network irregularities and, in particular, the detection and interpretation of spurious peaks is gaining in importance in all areas of electrical engineering, but especially in electronic data processing, since the problems of so-called "electromagnetic compatibility" (EMC) owing to the connected consumers (loads) of the low-voltage supply network are also becoming ever more complex owing to increasing mechanisation. Conventional network analysers operate using the principle of the RF amplifier, and are complicated and expensive. It often occurs that devices have been influenced without analysers which are connected to the network having indicated anything. According to the invention, the signals and pulses are converted into electric variables which can be processed more effectively, with the result that with the simple cost-effective device frequencies of up to more than 100 MHz can be optically displayed, detected by memories, and interpreted more effectively by connectable auxiliary devices. Technicians and service staff have a valuable test aid in determining and interpreting disturbing mechanisms on the public low-voltage supply networks.

Electromagnetic Modelling Methods for EMC Design

Abstract: Electromagnetic analysis by computer modelling can now be applied to a wide range of important EMC problems. There currently exist a variety of numerical modelling techniques, which have become available to the EMC industry through complicated computer programs. The major modelling and prediction methods for Electromagnetic design are reviewed and compared. Certain modelling techniques are identified as being preferential for the solution of particular EMC problems, but arguments are given that no one modelling technique can be identified as being suited to all EMC problems. A selection of commonly available computer programs are discussed and examples of their use made.

Experimental and analytic studies of the triggered lightning environment of the F106B

Abstract: The triggered lightning environment of the F106B aircraft is investigated. Scale modeling of the F106B with a metallized model was done to measure electric field enhancement factors on the aircraft and on canonically shaped conducting objects. These are then compared to numerically determined quantities. Detailed numerical modeling is done of the development of the triggered lightning channel. This is done using nonlinear air chemistry models to model a variety of physical phenomena which occur in a triggered lightning event. The effect of a triggered lightning strike on internal wires in the F106B is investigated using finite difference models and transmission line models to calculate the electromagnetic coupling of lightning currents through seams and joints of the aircraft to internal cables. Time domain waveforms are computed and compared to measured waveforms. The effect of thunderstorm particles on the initial triggering of a lightning strike is investigated. The electric field levels needed to cause air breakdown in the presence and absence of thunderstorm particles are calculated. This is done as a function of the size, shape, and density of the particles.

The umta rail transit emi/emc program: an overview and summary. final report

Abstract: This report gives a history of the UMTA Rail Transit Electromagnetic Interference and Electromagnetic Compatibility (EMI/EMC) program, together with a listing of significant achievements over the life of the program. This is the lead volume of a nine-volume set dealing with the theory, problems and solutions of electromagnetic incompatibility between solid state power systems and rail transit signaling systems. Specifics of conductive, inductive and radiated interference theory, data, tests and suggested test procedures are described in detail in the remaining volumes of this set. This report includes a listing of suggested test procedures and test reports for the EMI/EMC program.

Sources of Electromagnetic Interference

Abstract: Any device or apparatus that transmits, distributes, processes, or otherwise utilizes any form of electrical energy can be a source of EMI if any aspect of its operation generates conducted and/or radiated electromagnetic signals that can cause a degradation of performance of any other equipment or system that shares the same environment. Signals that are traceable to an electrical origin are essentially found everywhere: on the earth’s surface, in underground locations such as mines and tunnels, under water, in the atmosphere, and in outer space (1, 2).

Electromagnetic Measurement of and Location of Lightning

Abstract: This paper summarizes some techniques developed for electromagnetic measurements of lightning electromagnetic fields at Langmuir Laboratory. These included measurement of transient electric and magnetic fields at the ground surface, use of these fields to estimate location of the lightning and properties of the source, and use of time of arrival at different sensors to locate the source. These measurements are compared to acoustic and photographic measurements of the same events.

A Survey of EMI Measurements and Terminology

Abstract: This chapter is a survey of methods and nomenclature used in measurements of electromagnetic interference (EMI) emission and susceptibility characteristics of equipment and subsystems. The survey is divided into three categories of EMI measurements: 1. Equipment and subsystem level tests: The lowest level of EMI tests emphasizes components, equipment, and subsystems, as in MIL-STD-462, MIL-STD-449C, MIL-STD-704C, CISPR, FCC Rules 15 and 18, SAE J551C, and NACSEM 5100 (1). In addition to these EMI test items, this level covers tests on electrical filters used for EMC applications and on shielded enclosures to determine shielding effectiveness. 2. System- and vehicle-level tests: The intermediate level of EMI testing involves confirming that EMC exists at the system and vehicle level. Example are MIL-D-6015D(9) and MIL-STD-1541(14). These tests basically involve exercising the system in typical intentional modes of operation and recording whether any malfunction or degradation exists for any receptors or victims due to EMI.

Communications and Wave Filters

Abstract: Electrical filters used to control EMI may be divided into two types: communications or wave filters used in intersystem EMI control and power-line filters used in intrasystem EMI control (6). This chapter presents a summary of communication filters and filtering techniques, and the next chapter surveys EMI power-line filters.

Power-Line EMI Filters

Abstract: Most conducted forms of intrasystem EMI result from various equipment or systems sharing the same source of AC power mains (6). Here, an electrically noisy source may pollute the power distribution wiring by injecting broadband conducted emissions into wires that also feed other potentially susceptible equipments. In this instance, the common-mode noise voltage is generated across the power distribution source and circuit impedance and is therefore “seen” by all equipment connected to the power source. Another mechanism involves common impedance coupling in which two or more circuits are fed from a common regulated or unregulated power supply with an (usually unintentional) impedance element appearing in (i.e., in common with) both circuits. For example, this latter situation often occurs when two circuits share a common return path, such as a ground plane, for the power current, determines the level of induced voltage and the susceptibility of the interference depends upon the level of the path impedance, which, for a given current, determines the level of induced voltage; and the susceptibility of the potential victim circuit. Power mains pollution can also occur if the power lines are electromagnetically contaminated as a result of the coupling of radiated emissions, such as the signals from licensed transmitters, into the lines. The radio frequency (RF) noise is thence conducted into equipment circuits via the power-line conductors.