1、STD-BSI BS EN IS0 14744-2-ENGL 2001 = 3624669 0902 - present to the responsible inte - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references Attention
2、is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with their corresponding European publications. The British Standards which implement these international or European publications may be found in the BSI Stan
3、dards Catalogue under the section entitled “Intedonal Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for
4、their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN IS0 title page, pages 2 to 7 and a back cover. The BSI copyright notice displayed in this doc
5、ument indicates when the document was last issued. O BSI 04-2001 ISBN O 580 34197 6 - -_ - STD*BSI BS EN IS0 14744-2-ENGL 2001 1624669 0902843 bOT = EUROPEAN STANDARD EN IS0 14744-2 NORME EUROPENNE EUROPISCHE NORM April 2000 ICs 25.160.00 English version Welding - Acceptance inspection of electron b
6、eam welding machines - Part 2: Measurement of accelerating voltage characteristics (IS0 1 4744-2:2000) Soudage - Essais de rception des machines de soudage par faisceau dlectrons - Partie 2: Mesure des caractristiques de la tension dacclration (IS0 14744- 2:2000) Schweien - Abnahmeprfung von Elektro
7、nenstrahl- Schweimaschinen - Teil 2: Messen der Beschleunigungsspannungs-Kenngren (IS0 14744- 2:2000) This European Standard was approved by CEN on 3 January 2000. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standar
8、d the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three officiai versions (English, French, Ge
9、rman). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark,
10、Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMiTEE FOR STANDARDIZATION EUROPISCHES KOMITEE FR NORMUNG CO MIT EUROPEEN DE NORMALISATION Central Secretariat: rue de Stassart, 36 B-1050 B
11、russels Q 2000 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. NO. EN IS0 14744-2:2000 E STD-BSI BS EN IS0 14744-2-ENGL 2001 m 1624669 0902844 546 EN-IS0 14744-2:2000 Contents Page Foreword . 3 i Scope 4 2 Normative references . 4 3 Terms
12、anddefinitions 4 4 Testarrangement 4 General . 4 4.1 4.2 Testdevices 4 5 Measurement procedure 6 5.1 General . 6 5.2 Measuring the ripple 7 5.3 Measuring the stability . 7 5.4 Measuring the reproducibility 7 6 Evaluation . 7 Page 3 STD=BSI BS EN IS0 14744-2-ENGL 2001 W Lb24bb9 0902845 482 m EN IS0 1
13、4744-212000 Foreword The text of EN IS0 14744-2:2000 has been prepared by Technical Committee CENTC 121 “Welding“, the secretariat of which is held by DS, in collaboration with Technical Committee ISO/TC 44 “Welding and allied processes“. This European Standard shall be given the status of a nationa
14、l standard, either by publication of an identical text or by endorsement, at the latest by October 2000, and conflicting national standards shall be withdrawn at the latest by October 2000. According to the CENKENELEC internal Regulations, the national standards organizations of the following countr
15、ies are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. This draft European Standard is composed of the six f
16、ollowing parts: - Part 1 : Principles and acceptance conditions; - Fart 2: Measurement of accelerating voltage Characteristics; - Part 3: Measurement of beam current characteristics; - Part 4: Measurement of welding speed; - Part 5: Measurement of run-out accuracy; - Part 6: Measurement of stability
17、 of spot position. Page 4 EN IS0 14744-22000 1 scope This standard is intended for use when the characteristics of the accelerating voltage of electron beam welding machines complying with EN IS0 14744-1 is to be measured in connection with an aceptance inspection. It provides essential information
18、on the procedure and apparatus to be used for making the measurements. The accelerating voltage is one of the significant parameters in electron beam welding. When accelerating the electrons, the voltage should be stable and reproducible within given short-term and long-term limits. The purpose of t
19、he measurement is thus to check whether the variations in accelerating voltage are within specified limits. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in
20、the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to
21、 applies (including amendments). EN IS0 14744-1 :2000 Welding - Acceptance inspection of electron beam welding machines - Part 1 : Principles and acceptance Conditions (IS0 14744-1 : 2000) EN IS0 14744-3 Welding - Acceptance inspection of electron beam welding machines - Part 3: Measurement of beam
22、current caracteristics (IS0 14744-3 z 2000) 3 Terms and definitions For the purposes of this European Standard, the following term and definition applies, 3.1 accelerating voltage difference in electrical potential between the cathode and anode of the beam generator in the electron gun. 4 Test arran
23、gement 4.1 General The voltages usually present during electron beam welding at the output of the high-voltage generator, at the end of the high-voltage cable and in the beam generator cannot be safely measured without the use of special equipment. Since, generally, only the manufacturers of welding
24、 machines or high-voltage units have appropriate equipment at their disposal, it has proved expedient to measure the accelerating voltage at the manufacturers works. NOTE Attention should be paid to electrical safety levels during testing at high voltages and the need for appropriately trained/quali
25、fied personnel to carry out tests. Apart from these safety aspects, the test equipment shall also be capable of measuring the accelerating voltage over the entire range of beam current setting, .e. with the welding parameters set to conform to actual welding conditions. The main purpose of the follo
26、wing descriptions and illustrations of test arrangements is to enable uniform high-voltage measurements on electron beam welding machines to be made rather than to provide complete circuit diagrams. 4.2 Test devices A voltage divider shall be connected between the high-voltage unit and the electron
27、gun. Examples are shown in figures 1 and 2. The extent to which frequency compensation is required depends on the type of high-voltage generator. The accuracy of test arrangement shall be compatible with the requirements stated in EN IS0 14744-1. STD-BSI BS EN IS0 14744-2-ENGL 2001 1b24bb9 0902847 2
28、55 m Page 5 EN IS0 14744-2:2000 4 5 Ke 1 dgh-voltage generator 2 Bias control unit 3 Cathode heatin 4 High-voltage ca%e 1 5 High-voltage cable 2 6 Electron beam gun 7 Frequenc -compensated voltage divider lo4 : 1, Uhm, = 200 kV, R = 200 MR 8 R = 20 d measunng resistor 9 To oscilloscope, monitored vo
29、ltage Figure 1 - Example A of measurement of U, using a voltage divider For a division ratio of lo4 : 1, for example, an accelerating voltage, Ua, of 150 kV is reduced to a monitored voltage, Ua, of 15 V, which may be supplied to an oscilloscope. As the voltage divider is connected only to one of th
30、e cathode heatin conductors, a current of 0,75 mA flows to earth for a resistance of 200 MR and an accelerating voltage, U, of 950 kV. 3 Ke 1 d h-voltage generator 2 Cahode heatin and bias control unit 3 High-voltage ca-, U;,n and U, are maximum, minimum and average values observed during the period
31、 of observation. 5.3 Measuring the stability The average voltage shall be recorded continuously for a given operating period, using an instrument eliminating ripple. The percentage deviation shall be calculated as follows: whichever is the largest and where U, and U, are maximum and minimum observed
32、 values and U, is the initial value. 5.4 Measuring the reproducibility The accelerating voltage shall be switched on and the average monitored voltage shall be measured, using an instrument eliminating ripple. The accelerating voltage and the specified beam current shall subsequently be switched off
33、 and on several times and the corresponding average monitored voltages shall be recorded. The reproducibility shall be calculated as follows: whichever is the greater where U, and U, are maximum and minimum average values the initial value. bs rv d and U, is 6 Evaluation The measured values of rippl
34、e, stability and reproducibility shall be assessed by comparing them with the limit deviations specified in EN IS0 14744-1. _ _ STDOBSI BS EN IS0 34744-2-ENGL 2003 1624663 0902850 8LIT W BS EN IS0 14744-2:2001 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the in
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