BS-7815-1995 IEC-61087-1991.pdf
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1、BRITISH STANDARD BS 7815:1995 IEC 1087:1991 Guide for evaluating the discharges from a charged surface Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:57:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7815:1995 This British Standard, having been prepared un
2、der the direction of the Electrotechnical Sector Board, was published under the authority of the Standards Board and comes into effect on 15 July 1995 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference GEL/15 Draft announced in BSI News April 1995 ISBN
3、0 580 24197 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee GEL/15, Insulating material, upon which the following bodies were represented: British Ceramic Research Ltd. British Industrial Ceramic Manufacturers Associati
4、on Electrical and Electronic Insulation Association (BEAMA Ltd.) Electricity Association Federation of the Electronics Industry Rotating Electrical Machines Association (BEAMA Ltd.) Transmission and Distribution Association (BEAMA Ltd.) Amendments issued since publication Amd. No.DateComments Licens
5、ed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:57:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7815:1995 BSI 10-1999i Contents Page Committees responsibleInside front cover National forewordii 1Scope and object1 2Principle of the method1 3Test equipment1 4Cond
6、itioning and preliminary operations2 5Test procedure2 6Test results2 7Acceptance conditions3 8Test report3 Figure 1 Test specimen and test electrode3 Figure 2 Typical trace without discharges4 Figure 3 Typical trace with discharges4 List of referencesInside back cover Licensed Copy: London South Ban
7、k University, London South Bank University, Fri Dec 08 11:57:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7815:1995 ii BSI 10-1999 National foreword This British Standard has been prepared by Technical Committee GEL/15. It is identical with IEC 1087:1991 Guide for evaluating the discharges from
8、a charged surface, published by the International Electrotechnical Commission (IEC). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of its
9、elf confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be i
10、ndicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:57:22 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7815:1995 BSI 10-19991 1 Scope and object This Technical Report is used as a guide that applies to p
11、roducts, materials, plastic parts of equipment, electrically-insulated metal parts of such equipment, or complete equipment. It provides a test method to determine whether a product produces discharges when its surface has been charged, for example, by rubbing and thus be potentially the source of p
12、roblems arising from electrostatic charges and discharges. 2 Principle of the method The principle of the method consists, in a first step, in charging electrically by an appropriate procedure, for instance by rubbing the external part of the product placed on a large metallic plate (where this repr
13、esents an appropriate ground plane), and then, in a second step, in detecting if a discharge appears when an earthed test electrode approaches the charged area. When such a discharge appears, the electric charge transferred during the spark may be measured by an appropriate equipment and is compared
14、 to a limiting value, characteristic of a given electrostatic problem. Examples of relevant problems and risks are ignition of flammable gases, Interference with operation of electronic equipment and damage to semiconductor devices. 3 Test equipment The test equipment consists of three main parts: a
15、 charging device; a mobile test electrode which is driven at a given speed towards the test object; an electric equipment to measure and record the electric charge produced or transferred during the different steps of the test. 3.1 Charging device Any charging device, based on contact and separation
16、 such as rubbing or beating, can be used.1) The effectiveness of the charging device shall be verified in preliminary tests in that it can create a net surface charge approaching a density of at least 105 C/m2 on a highly insulating material, and an area of at least 200 cm2 shall be charged. The cha
17、rging device shall be specified with reference to the product and it would be described in the relevant individual standard. The charging can be achieved by hand with a suitable material with an appropriate shape. A rubbing speed and pressure providing maximum charge are used. For plane material sam
18、ples the rubbing materials shall be wrapped around a metal electrode with a flat lower surface with an area of at least 100 cm2 and a width of at least 7 cm. During the rubbing period there shall be a pressure on this lower surface between 400 Pa and 600 Pa. The charging device shall be electrically
19、 isolated from the operator and connected to earth by a measuring instrument. The operator shall be connected to earth by a wriststrap and hold the insulated rubbing electrode in his hand. The type of charging material shall be accurately described. Unless otherwise stated in the specification, thre
20、e types of materials should be used: a pure cotton fabric, wool or leather, as a conductive cloth; a material expected to produce a positive charge such as polyamide 11; a material expected to produce a negative charge such as polyacrylic fabrics. In some circumstances, d.c. corona charging may be u
21、sed. If tests are performed on site on a product on which there is already a charge, a charging device need not be used. 3.2 Moveable electrode Unless otherwise specified the electrode consists of a metal sphere 15 mm in diameter fitted on a motor driven vertical rod. The device is such that the sph
22、ere can be moved down and up at a constant speed. The test equipment is shown in Figure 1. The standardized characteristics are the following: speed of the electrode: 5 cm/s 1 cm/s; distance between sample and sphere at furthest extent: 300 mm 10 mm; drive reversal direction automatically switched o
23、n at a distance from the sphere to the product of 1 mm 0,5 mm to reach the same maximum distance of 300 mm 10 mm. 3.3 Charge meter The electric measurement circuit is shown in Figure 1. It consists mainly of a charge meter, which comprises a highly insulated and calibrated 10 nF to 100 nF capacitor
24、and a very high input resistance voltmeter, which is connected across the capacitor and has a range of 1 mV to 10 V, providing a time constant of at least 120 s. The output of the voltmeter shall be continuously recorded. 1) Different types of charging devices are under consideration in order to est
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