EN 61857-22-2008 en Electrical insulation systems - Procedures for thermal evaluation - Part 22 Specific requirements for encapsulated-coil model - Wire-wound electrical insulation.pdf

1、Electrical insulation systems Procedures for thermal evaluation Part 22: Specific requirements for encapsulated-coil model Wire-woundelectrical insulation system (EIS)BS EN 61857-22:2008raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI British Stand

2、ardsNational forewordThis British Standard is the UK implementation of EN 61857-22:2008. It isidentical to IEC 61857-22:2008. It supersedes BS EN 61857-22:2002 which iswithdrawn.The UK participation in its preparation was entrusted to Technical CommitteeGEL/112, Evaluation and qualification of elect

3、rical insulating materials andsystems.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2009ISBN 978 0 580 618

4、53 6ICS 29.080.30BRITISH STANDARDBS EN 61857-22:2008Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on Amendments issued since publicationAmd. No. Date Text affectedM

5、arch31 2009EUROPEAN STANDARD EN 61857-22 NORME EUROPENNE EUROPISCHE NORM October 2008 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Bru

6、ssels 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61857-22:2008 E ICS 29.080.30 Supersedes EN 61857-22:2002English version Electrical insulation systems - Procedures for thermal evaluation - Part 22: Specific requirements

7、 for encapsulated-coil model - Wire-wound electrical insulation system (EIS) (IEC 61857-22:2008) Systmes disolation lectriques - Procdures dvaluation thermique - Partie 22: Exigences particulires pour modle de bobine encapsule - Systme disolation lectrique (SIE) enroulements fil (CEI 61857-22:2008)

8、Elektrische Isoliersysteme - Verfahren zur thermischen Bewertung - Teil 22: Spezielle Bedingungen fr ein umhlltes Spulenmodell - Elektrisches Isoliersystem (EIS) aus Drahtwicklungen (IEC 61857-22:2008) This European Standard was approved by CENELEC on 2008-09-01. CENELEC members are bound to comply

9、with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard 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 Secret

10、ariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as th

11、e official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Po

12、rtugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 61857-22:2008 - 2 - Foreword The text of document 112/91/CDV, future edition 2 of IEC 61857-22, prepared by IEC TC 112, Evaluation and qualification of electrical insulating materials and systems, was submitte

13、d to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61857-22 on 2008-09-01. This European Standard supersedes EN 61857-22:2002. The editorial revisions make EN 61857-22:2008 compatible with Parts 1 and 21. The following dates were fixed: latest date by which the EN has to be impleme

14、nted at national level by publication of an identical national standard or by endorsement (dop) 2009-06-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2011-09-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International

15、Standard IEC 61857-22:2008 was approved by CENELEC as a European Standard without any modification. _ BS EN 61857-22:2008- 3 - EN 61857-22:2008 Annex ZA(normative) Normative references to international publications with their corresponding European publications The following referenced documents are

16、 indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE When an international publication has been modified by common modifications, indic

17、ated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 61857-1 2004 Electrical insulation systems - Procedures for thermal evaluation - Part 1: General requirements - Low-voltage EN 61857-1 2005 2 61857-22 IEC:2008 CONTENTS INTRODUCTION.5 1 Scope.6 2 Normative references .6

18、 3 Terms and definitions .6 4 Construction.7 4.1 General information.7 4.2 ECM components 7 4.3 Assembly of the ECM 7 4.4 Similarity of reference and candidate ECM 8 5 Number of test objects8 6 Test procedure .8 6.1 General .8 6.2 Initial screening test 8 6.2.1 General .8 6.2.2 Initial dielectric te

19、st .8 6.3 Thermal endurance test.9 6.3.1 Endurance test cycle .9 6.3.2 Thermal ageing .9 6.3.3 Mechanical stress10 6.3.4 Thermal shock.10 6.3.5 Moisture exposure .10 6.3.6 Dielectric diagnostic test10 7 End-of-life criterion.11 8 Analysing, reporting and classification11 Annex A (informative) Simila

20、rity of reference and candidate specimens .12 Bibliography13 Table 1 Initial dielectric tests for ECM9 Table 2 Dielectric diagnostic tests for ECM 10 BS EN 61857-22:200861857-22 IEC:2008 5 INTRODUCTION A series of parts that will make up IEC 61857 is currently being developed, each of which will add

21、ress a specific test object and/or application with an associated test procedure. Additional parts will be developed in cooperation with IEC technical committees responsible for equipment. BS EN 61857-22:2008 6 61857-22 IEC:2008 ELECTRICAL INSULATION SYSTEMS PROCEDURES FOR THERMAL EVALUATION Part 22

22、: Specific requirements for encapsulated-coil model Wire-wound electrical insulation system (EIS) 1 Scope This part of IEC 61857 provides a general-purpose procedure for the evaluation of wire-wound systems using a general purpose encapsulated-coil model (ECM) where the application is unknown. 2 Nor

23、mative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 61857-1:2004, Electrical in

24、sulation systems Procedures for thermal evaluation Part 1: General requirements Low-voltage 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 61857-1, as well as the following definitions, apply. 3.1 encapsulant electrical insulating material (EIM) tha

25、t completely encases the coil except for connections to the exterior, and is part of the electrical insulation system (EIS) NOTE The encapsulated-coil model (ECM) does not employ a supplemental shell. 3.2 encapsulation process of applying an encapsulant NOTE For the purpose of evaluating an electric

26、al insulation system (EIS), the process may consist of injection moulding, compression moulding, casting or other techniques. 3.3 bobbin form around which a coil is wound 3.4 coil continuous winding of insulated wire 3.5 coil-to-coil insulation electrical insulating material (EIM) between individual

27、 coils BS EN 61857-22:200861857-22 IEC:2008 7 3.6 earth ground (US) make an electric connection between a given point in a system or in an installation or in equipment and a local earth IEV 195-01-08 3.7 earth (ground) insulation electrical insulating material (EIM) between a coil and earthed metal

28、4 Construction 4.1 General information The ECM is useful in evaluating the compatibility of EIM used in a candidate EIS. It is equally capable of simulating the influences of actual manufacturing processes such as winding techniques, termination techniques and encapsulation. The essential parts of t

29、he ECM are a bobbin, winding wire, wire connectors and encapsulant. The winding wires may be connected to binding posts or to lead wires, either of which extends through the encapsulant wall. 4.2 ECM components The components of the encapsulated-coil model are as follows: a) Coil: the coils may be w

30、ound with two wires in parallel (bifilar winding) or may be wound with a single wire. b) Wire: winding wire, heavy film coated; 0,4 mm to 0,6 mm diameter wire size is preferred. c) Earth insulation: the EIM used as the bobbin and the EIM used as the encapsulant function as coil-to-earth insulation.

31、An EIM evaluated only as a coil bobbin shall not also be used as an encapsulant material. An EIM used as an encapsulant shall be evaluated as such. d) Tape: electrical tape may be used but unless electrically stressed and evaluated is not part of the EIS. e) Connectors: the winding wires are connect

32、ed inside the encapsulant to binding posts or lead wires. These connections are essential parts of the ECM. f) Electrical impregnating resin/varnish: this may be part of the EIS if applied prior to the encapsulation process. NOTE A metal frame or a lamination stack that may be incorporated into the

33、test object is not an essential part of the test object if it does not function as a fault path. 4.3 Assembly of the ECM Assemble the ECM as follows: a) Wind the winding wire over the bobbin using accepted winding techniques. b) As appropriate, use electrical grade tape or other components to secure

34、 the winding wire in place. c) Connect the winding wire to the binding posts or lead wires. d) If part of the candidate EIS, apply impregnating resin/varnish. e) Apply the encapsulant material. BS EN 61857-22:2008 8 61857-22 IEC:2008 4.4 Similarity of reference and candidate ECM The physical shape a

35、nd assembly of the reference and candidate ECM must be similar. It is essential that the size of the winding wire used in the reference and candidate ECM be within 0,2 mm of each other. Refer to Annex A for more information. Details of the construction of the reference and candidate ECM shall be rep

36、orted according to 7.4 of IEC 61857-1:2004. 5 Number of test objects The minimum number of test objects for each EIS and for each ageing temperature shall be ten. 6 Test procedure 6.1 General All test objects shall be subjected to initial screening tests followed by repeated thermal endurance test c

37、ycles in the following order: a) a thermal ageing subcycle; b) a subcycle of pre-diagnostic mechanical stress, other pre-diagnostic requirements and moisture exposure, in that order; c) a dielectric diagnostic test. 6.2 Initial screening test 6.2.1 General Prior to exposure to an elevated temperatur

38、e on the first thermal ageing subcycle, all test objects shall be subjected to initial screening tests in order to eliminate defective test objects. The initial screening tests shall consist of the following steps and shall be conducted in the order given: a) visual inspection; b) initial dielectric

39、 test (see 6.2.2); c) mechanical stress (see 6.3.3); d) thermal shock, as required (see 6.3.4) e) moisture exposure (see 6.3.5); f) dielectric diagnostic test (see 6.3.6). 6.2.2 Initial dielectric test An initial screening test using dielectric techniques shall be performed on each ECM test object p

40、rior to application of other prediagnostic stresses and thermal ageing, see Table 1. BS EN 61857-22:200861857-22 IEC:2008 9 Table 1 Initial dielectric tests for ECM Test Method Voltage V Acceptance criteria Wire in a single strand coil Change of resistance Apply a direct current voltage that will re

41、sult in a maximum admissible current density at which the active resistance of the winding can be measured. a3 % reduction of the resistance for the coil design Wires in bifilar coils Conductor to conductor 400 40 0,5 A to 0,75 A Coil-to-coil (for multiple coil constructions) Dielectric withstand 2

42、000 100 (40 10) mA Earth insulation Dielectric withstand 2 000 100 (40 10) mA a Maximum 1 A/mm2of cross-section. The following procedure shall then be followed: an initial dielectric test voltage shall be applied for a minimum of 60 s; failure shall be current flow as defined above prior to completi

43、on of the time period; frequency of the test voltage shall be between 48 Hz and 62 Hz. NOTE Instantaneous application of full voltage is not recommended. It is recommended that surge protectors be included in the test circuit to eliminate unintended high voltage spikes. For test objects evaluated by

44、 applied voltage, pre-calibrated electromechanical over-current circuit-breakers with a trip time of 2 s to 3 s have been used successfully to detect failure. The cause of failure shall be determined. When the failure is within the EIS, it shall eliminate that ECM from further testing. When the fail

45、ure is not within the EIS and it can be repaired without disturbing the EIS, the ECM may be retested and returned to the test programme if it passes. 6.3 Thermal endurance test 6.3.1 Endurance test cycle Following the initial screening tests, all test objects shall be subjected to repeated thermal e

46、ndurance test cycles in the following order: a) thermal ageing subcycle; b) mechanical stress subcycle; c) thermal shock subcycle; d) moisture exposure subcycle; e) dielectric diagnostic test. 6.3.2 Thermal ageing Thermal ageing, comprising selection of ageing temperature, initial ageing periods and

47、 ageing procedures shall be conducted in accordance with 6.3 of IEC 61857-1:2004. Ovens shall be used in accordance with 6.3.4 of IEC 61857-1:2004. BS EN 61857-22:2008 10 61857-22 IEC:2008 6.3.3 Mechanical stress Mechanical stress shall be applied by mounting the test objects on a vibration table an

48、d exposing them between 55 min to 65 min of sinusoidal vibration at a frequency between 48 Hz and 62 Hz, with a constant acceleration of (14,7 3) ms2. No voltage shall be applied during this period. 6.3.4 Thermal shock Unless agreed to by all interested parties, both the reference and candidate EIS

49、shall be exposed to a low-temperature thermal shock. Thermal shock shall be applied by placing ECMs directly from ambient conditions into a low-temperature chamber at (20 5) C for at least 2 h. No voltage shall be applied during this period. 6.3.5 Moisture exposure Moisture exposure with visible condensation shall be applied in accordance with 6.6 of IEC 61857-1:2004. 6.3.6 Dielectric diagnostic test Following each ageing cycle and conditio