AWS A10 1M-2007 Specification for Calibration and Performance Testing of Secondary Current Sensing Coils and Weld Current Monitors used in Single-Phase AC Resistance Welding (1st E.pdf

1、AWS A10.1M:2007An American National StandardSpecification forCalibration andPerformanceTesting ofSecondary CurrentSensing Coilsand Weld CurrentMonitors used inSingle-PhaseAC ResistanceWelding550 N.W. LeJeune Road, Miami, FL 33126AWS A10.1M:2007An American National StandardApproved by theAmerican Nat

2、ional Standards InstituteMarch 5, 2007Specification for Calibration andPerformance Testing of Secondary CurrentSensing Coils and Weld Current Monitors usedin Single-Phase AC Resistance Welding1st EditionPrepared by theAmerican Welding Society (AWS) A10 Committee on Instrumentation for WeldingUnder t

3、he Direction of theAWS Technical Activities CommitteeApproved by theAWS Board of DirectorsAbstractThis specification sets forth accepted methods for testing and describing the performance of Rogowski-type air corecurrent sensing coils (CSC) and weld current monitors (WCM) used in the measurement of

4、single-phase ac resistancewelding currents. A definition of terms relevant to this measurement is included. CSC and system tests and calibrationmethods are described in detail. Detailed information that shall be made available to the user are prescribed.iiAWS A10.1M:2007International Standard Book N

5、umber: 978-0-87171-068-0American Welding Society550 N.W. LeJeune Road, Miami, FL 33126 2007 by American Welding SocietyAll rights reservedPrinted in the United States of AmericaPhotocopy Rights. No portion of this standard may be reproduced, stored in a retrieval system, or transmitted in anyform, i

6、ncluding mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyrightowner.Authorization to photocopy items for internal, personal, or educational classroom use only or the internal, personal, oreducational classroom use only of specific clients is granted

7、 by the American Welding Society provided that the appropriatefee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, tel: (978) 750-8400; Internet:.iiiAWS A10.1M:2007Statement on the Use of American Welding Society StandardsAll standards (codes, specifications, recomme

8、nded practices, methods, classifications, and guides) of the AmericanWelding Society (AWS) are voluntary consensus standards that have been developed in accordance with the rules of theAmerican National Standards Institute (ANSI). When AWS American National Standards are either incorporated in, orma

9、de part of, documents that are included in federal or state laws and regulations, or the regulations of other govern-mental bodies, their provisions carry the full legal authority of the statute. In such cases, any changes in those AWSstandards must be approved by the governmental body having statut

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11、tandard must be by agreement between the contracting parties.AWS American National Standards are developed through a consensus standards development process that bringstogether volunteers representing varied viewpoints and interests to achieve consensus. While AWS administers the processand establis

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18、ments of this standard may only be obtained by sending a request,in writing, to the appropriate technical committee. Such requests should be addressed to the American Welding Society,Attention: Managing Director, Technical Services Division, 550 N.W. LeJeune Road, Miami, FL 33126 (see Annex G).With

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20、r individuals giving them. These individualsdo not speak on behalf of AWS, nor do these oral opinions constitute official or unofficial opinions or interpretations ofAWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation.This standard is su

21、bject to revision at any time by the AWS A10 Committee on Instrumentation for Welding. It must bereviewed every five years, and if not revised, it must be either reaffirmed or withdrawn. Comments (recommendations,additions, or deletions) and any pertinent data that may be of use in improving this st

22、andard are required and should beaddressed to AWS Headquarters. Such comments will receive careful consideration by the AWS A10 Committee onInstrumentation for Welding and the author of the comments will be informed of the Committees response to thecomments. Guests are invited to attend all meetings

23、 of the AWS A10 Committee on Instrumentation for Welding toexpress their comments verbally. Procedures for appeal of an adverse decision concerning all such comments areprovided in the Rules of Operation of the Technical Activities Committee. A copy of these Rules can be obtained fromthe American We

24、lding Society, 550 N.W. LeJeune Road, Miami, FL 33126.This page is intentionally blank.ivAWS A10.1M:2007vAWS A10.1M:2007DedicationDr. V. AnanthanarayananThis document is dedicated to Dr. V. Ananthanarayanan(Anthony). Without his vision, leadership, and persistence,neither this document nor the A10 T

25、echnical Committeewould exist.This page is intentionally blank.viAWS A10.1M:2007viiAWS A10.1M:2007PersonnelAWS A10 Committee on Instrumentation for WeldingK. Ymker, Chair RoMan Manufacturing, IncorporatedR. Gupta, Secretary American Welding SocietyD. Destefan High Current Technologies, IncorporatedR

26、. M. Dull Edison Welding InstituteJ. Farrow WTC R 1 106henries) ornanohenries (abbreviated nH; 1 109henries). ForCSCs used with weld current monitors, the CSC mutualinductance is typically in the range of 0.2 H to 0.7 H.For the purposes of this specification, the mutual induc-tance of the CSC is con

27、sidered to be independent offrequency.The CSC manufacturer needs to know the input imped-ance of the WCM to which the output of the CSC shallbe connected. Only then can the CSC output be properlytrimmed to provide the expected effective mutual induc-tance. It is common practice to adjust the effecti

28、vemutual inductance of a CSC with the use of added resis-tor(s). These resistors are often physically located in theelectrical connector of the CSCs output cable. Seriesand/or parallel adjusting schemes are commonly used.The effective mutual inductance of the CSC is dependentupon the external electr

29、ical load impedance to which it isconnected. The effective mutual inductance at the WCMmanufacturers recommended load impedance shall bestated. In addition, the effective mutual inductance at no-load impedance may be stated. The no-load impedance isdefined as a load equal to or greater than 1 M.A va

30、lue of CSC transimpedance may be provided, butshall not be used as a sole characteristic that describesthe CSC sensitivity. In all instances, if a transimpedancevalue is given, it shall be accompanied with a value forfrequency and load impedance under which it applies.The value of transimpedance, if

31、 used, shall be stated inunits of ohms, milliohms, or microohms, as appropriate.This value is commonly expressed as “millivolts perthousand amperes” at a stated frequency which is equiva-lent to units of microohms. The internationally acceptedscientific units of ohms, milliohms, or microohms arepref

32、erred over the use of the expression “millivolts perthousand amperes.”The mutual inductance calibration shall be performed ina 1/R-type magnetic field. A 1/R-type magnetic field isonly created by an infinitely long straight conductor witha circular cross section when a current is flowing alongthe le

33、ngth of the conductor. The field is purely tangentialto the single center conductor. The magnetic fieldbeyond the outside of the conductor varies inversely withthe distance R to the center of the conductor in a radialdirection. Ideally, there are no other field contributionsfrom any other source, es

34、pecially the return conductor.It is difficult to generate an ideal 1/R field. A practical,proven and suggested means to implement the generationof a suitable approximation of a 1/R-type magnetic field iswith the use of a coaxial cage arrangement. The coaxialcage, which may be cylindrical or comprise

35、d of large flatrectangular conductors and a rigid straight center conduc-tor with a round cross section. Sections through typicalhexagonal and circular coaxial cages are shown in Figure1. The coaxial cage geometry shall be such as to develop asuitable 1/R-type magnetic field approximation in the tes

36、tenvelope during the mutual inductance calibration test.The sizes of the central and return conductors shall beappropriate for the current range used. Typical diameterof the center conductor is 38 mm to 50 mm. Practicalcage diameters range from 300 mm to 600 mm, and theinside length range from 300 m

37、m to 900 mm. The thick-ness of the outer walls and end plates of the cage is typi-cally 6 mm to 12 mm thick. The inside of the cage mustbe sufficiently large to permit mounting the center of theCSC around the center conductor while maintaining asuitable clearance between the CSC and the inside walls

38、of the cage. The opposing design criteria are to keep thecage small to minimize the insertion impedance of thecage in the high current path, while simultaneously pro-viding sufficient working volume inside the cage toaccommodate the CSC being calibrated. Smaller cagesare less expensive to fabricate

39、and are more portable.Additionally, the thick outside walls of the cage provideseddy-current shielding from external fields.The CSC mutual inductance calibration shall be per-formed in a 1/R-type magnetic field equal to or betterthan that generated by a coaxial cage as described herein.If a coaxial

40、cage is not used, it is the responsibility of theuser to ensure, either through measurement or modelingAWS A10.1M:20074of the magnetic field, that the magnetic field is a suitableapproximation of the field produced by a coaxial cage, orthat of an ideal 1/R field.3.1.1 Equipment(1) Current source. Th

41、is is either a calibrated currentsource, or an uncalibrated current source used with thecalibrated current sensor listed next. In either instance,the source or the sensor must be calibrated in the fre-quency and current ranges used for the tests. The currentwaveform must be nominally a full-wave sin

42、usoid. Wave-forms other than sinusoidal will introduce frequencydependant errors.(2) Reference Current Sensor and Display. Not re-quired if the current source is calibrated.(3) Coaxial cage as in Figure 1.(4) Frequency counter.(5) AC voltmeter capable of measuring the output ofCSC with an input impe

43、dance of 1 megohm or greater.(6) Load resistor, value recommended by the WCMmanufacturer, typically 1000 ohms 1% low inductanceresistor. (Recommend the use of a metal film resistor;avoid using a wire wound resistor.) When the mutualinductance is being determined for a “no load” test con-dition, this

44、 load resistor is not used.3.1.2 Setup. For the mutual inductance calibration,the CSC shall be placed in the coaxial cage during testingso that the following conditions are met. The distancefrom the end plates to any part of the CSC shall be noFigure 1Hexagonal and Circular Coaxial Cages Typically U

45、sedfor Mutual Inductance Testing of a CSCAWS A10.1M:20075less than 5 cm or 10% of the coaxial cage length, which-ever is greater.(1) The distance from the return current plate(s) (i.e.,circular shells) to any part of the CSC shall be no lessthan 1cm or 5% of the shortest distance between the cen-ter

46、 bus and the return current plate, whichever is greater.(2) If a hexagonal coaxial cage is used, the CSC shallbe placed inside a circular envelope in which the radialdistance from the center of the bus is no greater than theshortest radial distance less 1 cm or 5% of the shortestdistance. The shape

47、of the CSC should not be deformedwhen it is placed in the coaxial cage for testing.(3) For CSCs having a circular shape, the CSC shallbe placed radially in the coaxial cage such that the centerof the CSC coincides with the center conductor of thecage and that it is oriented with the plane of the CSC

48、perpendicular to the center conductor.(4) If the CSC has a tear-drop or elliptical shape, itshall be centered on the intersection of its two axes (forexample, see Figure 3).(5) Ensure that the CSC cable connector is accessiblefrom the outside of the cage.Figure 2 is a photograph of a typical hexagon

49、al coaxialcage. The top plate has been removed to facilitate a viewof the CSCs placed inside the coaxial cage for testing.The CSCs placed inside the coaxial cage may be Refer-ence CSCs, UUTs, or both. Figure 3 shows a “tear-drop”shaped CSC and the intersection of the two axes whichdefines the “center” of the CSC.Figure 4 shows a schematic of the required test setup.The test procedure is described below. Allow sufficientwarm up time for all instruments and the CSC to providerequired stability. CSCs transported from one location toanother must be given sufficient time to stabiliz