1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 6404 : Part 20 : 1996
2、ICS 29.040.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Magnetic materials Part 20. Resistance and temperature classification of insulation coatingsThis British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the au
3、thority of the Standards Board and comes into effect on 15 September 1996 BSI 1996 The following BSI references relate to the work on this standard: Committee reference ISE/NFE/5 Draft for comment 95/706117 DC ISBN 0 580 26203 0 BS 6404 : Part 20 : 1996 Amendments issued since publication Amd. No. D
4、ate Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee ISE/NFE/5, Magnetic alloys and steels, upon which the following bodies were represented: British Iron and Steel Producers Association Electricity Associati
5、on Institute of Physics National Physical Laboratory Rotating Electrical Machines Association (BEAMA Ltd.) Transmission and Distribution Association (BEAMA Ltd.) University of Sunderland Wolfson Centre for Magnetics Technology Co-opted membersBS 6404 : Part 20 : 1996 BSI 1996 i Contents Page Committ
6、ees responsible Inside front cover Foreword ii Introduction 1 1 Scope 1 2 References 1 3 Classification 1 4 Properties of insulation coatings 1 5 Resistance measurements using the dual electrode method 2 6 Temperature/time designation 3 Tables 1 Specified values of resistance grades 2 2 Temperature/
7、time designation of insulation coatings 3 List of references Inside back coverii BSI 1996 BS 6404 : Part 20 : 1996 Foreword This British Standard has been prepared by Technical Committee ISE/NFE/5. It is based on appendix D of BS 6404 : Part 2 : 1985 which is withdrawn and replaced by BS 6404 : Part
8、 2 : 1996, and appendix D of BS 6404 : Section 8.4 : 1986 which is also withdrawn and replaced by BS EN 10106 : 1996. This standard is one of the series of British Standards based on the IEC 404 series, Magnetic materials. The following Parts of the British Standard have been published or will short
9、ly be published. Part 1 Classification Part 2 Methods of measurement of the magnetic properties of electrical steel sheet and strip by means of an Epstein frame Part 3 Methods of measurement of the magnetic properties of magnetic sheet and strip by means of a single sheet tester Part 4 Methods of me
10、asurement of the d.c. magnetic properties of solid steels Part 5 Permanent magnet (magnetically hard) materials Methods of measurement of magnetic properties Part 6 Methods of measurement of the magnetic properties of isotropic nickel-iron soft magnetic alloys, types E1, E3 and E4 Part 7 Method of m
11、easurement of coercivity of magnetic materials in an open magnetic circuit Part 8 Individual materials Section 8.1 Specification for magnetically hard materials Section 8.2 Specification for cold-rolled, magnetic, non-oriented, alloyed steel strip delivered in the semi-processed state Section 8.3 Sp
12、ecification for cold-rolled, magnetic, non-oriented, non-alloyed steel strip delivered in the semi-processed state Section 8.4 Specification for cold-rolled, magnetic, non-oriented, magnetic steel sheet and strip delivered in the finally annealed state Section 8.5 Specification for steel sheet and s
13、trip with specified mechanical properties and magnetic permeability Section 8.6 Specification for soft magnetic metallic materials Section 8.7 Specification for grain-oriented magnetic steel sheet and strip Section 8.8 Specification for thin magnetic steel strip for use at medium frequencies Section
14、 8.9 Standard specification for sintered soft magnetic materials Section 8.10 Specification for magnetic materials for use in relays Part 9 Methods for determination of the geometrical characteristics of magnetic steel sheet and strip Part 10 Methods of measurement of magnetic properties of magnetic
15、 steel sheet and strip at medium frequencies Part 11 Method of test for the determination of surface insulation resistance of magnetic steel and strip Part 12 Guide to methods of assessment of temperature capability of interlaminar insulation coatings Part 13 Methods of measurement of density, resis
16、tivity and stacking factor of electrical steel sheet and strip Additional Parts and Sections of IEC 404 will be published and are expected to provide a basis for additional Parts of BS 6404. BSI 1996 1 BS 6404 : Part 20 : 1996 Introduction The magnitude of eddy currents flowing between laminations i
17、n a magnetic circuit subjected to an alternating magnetic field is a function of: the interlaminar resistance; the magnetic flux density; the core density; the frequency. In general the more powerful the machine or transformer, the higher the value of interlaminar resistance required to limit the ed
18、dy currents, and hence the additional loss, to acceptable values. The life of insulation materials is also a function of their composition and the temperatures at which they operate. It is important therefore for designers of a.c. magnetic circuits to select an insulation coating for the laminations
19、 which will match the design requirements. Moreover, it is convenient for both users and producers of electrical steel to standardize the resistance of coatings into a limited number of ranges, based on insulation coating resistance. 1 Scope This standard specifies general requirements for resistanc
20、e grades of insulation coatings as defined in this Part of BS 6404. The preferred values of temperature/time capability, derived from BS 6404 : Part 12, are also covered. This Part of BS 6404 applies to both oriented and non-oriented materials as specified in BS EN 10106, BS EN 10107 and BS 6404 : S
21、ection 8.8. It can also apply to semi-processed material as defined in BS EN 10126 and BS EN 10165, provided the coating can withstand the decarburizing heat treatment recommended by the supplier. 2 References 2.1 Normative references This Part of BS 6404 incorporates, by dated or undated reference,
22、 provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back cover. For dated references, only the edition cited applies; any subsequent amendments to or revisions of the cited publication appl
23、y to this British Standard only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments. 2.2 Informative references This British Standard refers to other publications that provide informati
24、on or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Classification Insulation coatings shall be classified according to their temperature withstand capability and also
25、 by a grade designation based on the resistance of the insulation coating at ambient temperature using a specified method of measurement. The principles of temperature withstand capability are defined in BS 6404 : Part 12. It also defines preferred values of temperature/time designations from which
26、the standardized values in this Part of BS 6404 are derived. NOTE. It is recognized that the correlation of insulation coating resistance values between different measurement methods is very difficult and hence the resistance grade designations specified in this Part of BS 6404 relate only to the sp
27、ecified method of measurement and therefore differ from those in BS 6404 : Part 12. 4 Properties of insulation coatings 4.1 General The insulation coating shall be uniformly applied, adherent and free from dust. The coating shall be sufficiently adherent so that it does not become detached during sh
28、earing operations and when tested for adhesion at a temperature of (23 5) C using a mandrel of 30 mm diameter in accordance with BS 6404 : Part 12. 4.2 Resistance grade The resistance of the coating applied to a commercially smooth surface shall be specified by means of one of the grades defined in
29、table 1 for coatings measured in accordance with clause 5. NOTE. The inclusion of a resistance grade or preferred temperature capability in this Part of BS 6404 does not necessarily imply that all resistance grades and temperature capabilities are available from electrical steel suppliers. It may be
30、 necessary for the user to apply additional coatings or processing to achieve some specified values. The purchaser is responsible for ensuring, in consultation with the supplier, that the coating specified is suitable in other respects, (e.g. weldability, chemical composition) for the application. 4
31、.3 Stacking factor NOTE. The application of the insulation coating may reduce the stacking factor of the material. If there are special requirements in respect of stacking factor, these should be the subject of agreement between the supplier and the purchaser. If required, stacking factor shall be m
32、easured in accordance with BS 6404 : Part 13.2 BSI 1996 BS 6404 : Part 20 : 1996 5 Resistance measurements using the dual electrode method 5.1 Test specimen The test specimen shall be of such a size that the electrode faces are sufficiently remote from cut edges for measurements to be representative
33、 of the main body of the material supplied. Sufficient specimen area for 100 discrete readings shall be provided such that readings are taken at points across the full width of the sheet or strip. 5.2 Apparatus 5.2.1 Contact assembly. The instrument shall consist of a vertical plunger carrying a cir
34、cular electrode of contact area 645 mm 2 which can be brought into contact with a fixed lower electrode of the same shape and face area. The edges of both electrodes shall have a radius of 0,5 mm. The faces of the electrode shall be made of tool steel or other suitable material having a hardness of
35、greater than 250 HV 10 when tested in accordance with BS 427. The electrode faces shall be accurately lapped to give intimate contact over the area of the electrodes. A surface finish of less than 0,25mm Ra as specified in BS 1134 : Part 1 is recommended. The fixed electrode shall be mounted on a re
36、silient support base to facilitate accurate self alignment of the sheet and the electrode. NOTE. The test specimens should be supported on a platform surrounding the lower electrode. The platform should be in the same plane as the top surface of the lower electrode when the electrode is subjected to
37、 the specified pressure. A load of 450 N shall be applied to the movable electrode producing a pressure of 0,7 N/mm 2 at the electrode surfaces. To check the intimacy of the contact of the two electrodes the arrangement shall be periodically checked by placing a tissue paper and superimposed carbon
38、paper between the electrodes. During this check the load shall be applied to the upper electrode and the resulting print on the tissue paper shall be noted. The correct print should be an even, circular smudge on the tissue paper. Any misalignment of the electrodes, shown by a reduction in area of t
39、he circular smudge, shall be corrected. 5.2.2 Electrical arrangement. A sinusoidal potential difference of 250 mV 10 mV r.m.s. at a frequency in the range 45 Hz to 65 Hz shall be maintained across the electrodes, over the range of inter-electrode resistance variation between 100V and 0,2V, and betwe
40、en 1000V and 0,1V if required. NOTE. The supply may be derived from a negative feedback electronic amplifier arranged to regulate the voltage. 5.3 Measuring procedure The temperature of the test shall be within the range of 10 C to 30 C. The r.m.s. current passed between the two electrodes at the ap
41、plied pressure and voltage specified in 5.2.1 and 5.2.2 respectively shall be measured with an error not exceeding 1 %. Care shall be taken not to subject the specimens to a voltage greater than 260 mV. The readings shall be made so that they have an even distribution over the area of the test speci
42、men. If only a small specimen area is available, it shall be permissible to make only 40 readings. 5.4 Determination of insulation coating resistance With the applied voltage of 250 mV 10 mV r.m.s. the insulation coating resistance is taken as one quarter of the reciprocal of the measured r.m.s. cur
43、rent, in Amperes, and the test data shall be given in a series of calculated resistance values. The results shall be expressed as x % of the readings equal to or greater than R 1 and y % of the readings equal to or greater than R 2 , where R 1 and R 2 are specified marker values. NOTE. The percentag
44、e of readings equal to or greater than a series of marker values, e.g. 0,2V,1V ,2V ,5V ,1 0V ,2 5V , and 100V can be plotted on logarithmic probability paper to give a substantially straight line, the slope and position of which reflects the quality of the insulation. The test described evaluates a
45、sheet as a whole, taking account of both surfaces. In the case of sheets specifically insulated on one side only, the same test is used. 5.5 Insulation resistance measurements using the dual electrode method When tested using the method described in this clause, the grade shall be determined such th
46、at 80 % of the readings shall be greater than R 80 and 50 % of the readings greater than R 50 . R 80 , R 50 and the corresponding grades are defined in table 1. Table 1. Specified values of resistance grades Resistance grade Insulation coating minimum resistance ohm R 80 R 50 A 0.2 1 B21 0 C52 5 BSI
47、 1996 3 BS 6404 : Part 20 : 1996 6 Temperature/time designation NOTE.1. The performance of insulation coatings in service is a function of their type and their working environment, of which two of the most important parameters are temperature and the time at which a coating is held at that temperatu
48、re. BS 6404 : Part 12 envisages the allocation of one or more temperature/time designations to coatings to characterize their ability to withstand the temperatures of process and service conditions. The specified temperature/time designation shall be selected, when required, from table 2. It shall b
49、e based on a type test certified by the supplier in accordance with BS 6404 : Part 12, except that the resistance grades shall be as defined in table 1. Table 2. Temperature/time designation of insulation coatings Designation Temperature of testing C Duration of heating h 150/168 150 168 180/168 180 168 200/168 200 168 250/168 250 168 150/2500 150 2500 180/2500 180 2500 200/2500 200 2500 250/2500 250 2500 400/6 400 6 500/0.5 500 0.5 750/2 750 2 800/2 800 2 NOTE.2. If insulated material is required for subsequent annealing or welding, the manufacturer should be
