IEEE 1C-1954 - AIEE Test Code for Evaluation of Systems of Insulating Materials for Random-Wound Electric Machinery.pdf

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1、AIEE No. 1C Jan. 1954 IEEE STANDARDS ARCHIVES TO NOT REMOVE Test Code for EVALUATION of SYSTEMS of INSULATING MATERIALS for RANDOM-WOUND ELECTRIC MACHINERY Issued for trial use as a proposed supplement to AIEE No. 1 Published by AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS 33 West Thirty-ninth Street,

2、 New York 18, N. Y. Development of the Standards of the American Institute of Electrical Engineers Recognizing the importance in the development of electrical engineering, of standardiza tion in the electrical field, the AIEE in 1898 appointed a Committee on Standardization, consisting of seven memb

3、ers having qualifications and experience from designing, manufac turing and operating standpoints. The report of this Committee was accepted at a meeting of the Institute in June 1899. Experience gained in applications of the standards and further developments in electric apparatus and methods showe

4、d the necessity of revision, and a committee was appointed which after consultation with manufacturing and operating engineers presented the first revised report on Standardization Rules of the AIEE in June 1902. The next revision was undertaken by a committee of ten, which presented its report in M

5、ay 1906. In September 1906, a Standards Committee of eleven members was appointed for further revision, and its report was presented in June 1907. The appreciation of the importance and value of standardization resulted in the forma tion of a Standing Committee, with the title of Standards Committee

6、 of the AIEE. This became effective in the Constitution of June 1907. The scope and amount of work necessitated increasing the number of members from time to time until in 1922 there were 37 members divided into a number of subcommittees specializing on various subjects. AIEE Standards published in

7、a single volume as each revision was adopted were generally accepted as standards of the electrical industry of the United States since the adoption of the first report in 1899. Subsequent reports on standards were made and pub lished, in some cases in several editions. The dates of adoption by the

8、Board of Directors of such reports are as follows: June 20, 1902; June 21, 1907; June 27, 1912; July 10, 1914; June 30, 1915; June 28, 1916; November 8, 1918; October 8, 1920, and June 29, 1922. On June 29, 1922, in view of the increasing complexity of the work, a reorganization of the Standards Com

9、mittee was effected, and a working organization established which pro vided for an increase in standardization work and for the appointment on Working Commit tees of the Standards Committee of non-Institute members. The present plan under which the Institute Standards are being issued involves the s

10、epa ration of the complete body of standards into more than forty sections, each published as a separate pamphlet and dealing with a specific subject. Each section of the standards has been formulated either by a subcommittee of the Standards Committee which was made as rep resentative as possible f

11、or the work in hand, by an AIEE Technical Committee or subcom mittee, or by a Sectional Committee organized according to the procedure of the American Standards Association. The division of the standards into a number of separate publications simplifies the process of keeping the standards revised t

12、o conform with the latest develop ment and enables those interested in a particular field to obtain in concise form the material relating to that field. In framing the Institute Standards the chief purpose has been to define terms and conditions which characterize the rating and behavior of electric

13、 machinery and apparatus, with special reference to the conditions of acceptance tests. The AIEE Standards Committee takes this occasion to draw attention to the value of suggestions based upon experience gained in the application of the standards to general practice. Any suggestions looking toward

14、improvements in the standards will be welcomed for the guidance of the Committee in preparation of future editions, and should be communicated to the Secretary of the AIEE Standards Committee, 33 West 39th Street, New York 18, N. Y. 2 CONTENTS Introduction 5 PurposeMethods of Evaluation 5 Summary 6

15、1. Insulation Test Specimens 6 1-1. Scope1-2. Actual Equipment1-3. Model Motors1-4. Other Test Specimens 7 2. Test Exposures2-1. Scope 7 2-2. Temperature Exposure 7 2-3. Mechanical Stress Exposure 8 2-4. Moisture Exposure 9 3. Voltage Checks3-1. Recommended Check Voltages 9 Bibliography 10 3 ACKNOWL

16、EDGMENT The Institute wishes to acknowledge its indebtedness to those who have so freely given their time and knowledge and have conducted experimental work on which many of the AIEE Test Codes are based. This Test Code has been prepared by the Working Group in Insulation For Rotating Machines of th

17、e Subcommittee on Insulation (of the AIEE Rotating Machinery Committee). Members who participated in the pre paration of this Test Code are as follows: P. L. Alger, Chairman L. J. Berberich J. F. Dexter J. L. Fuller W. T. Gordon R.-4Iarrmgtoir, Secretary J. L. Kuehlthau G. E. McCann A. T. McClinton

18、G. L. Moses W. W. Pendleton E. I. Pollard F. C. Rushing C. L. Sidway 4 Test Code of the American Institute of Electrical Engineers EVALUATION OF SYSTEMS OF INSULATING MATERIALS FOR RANDOM-WOUND ELECTRIC MACHINERY INTRODUCTION Purpose.The chief purpose of this test code is to classify insulation syst

19、ems in accordance with their temperature limits by test, rather than by chemical composition. The intention is, first, to classify according to the recognized A, B, and H categories, whose usual continuous hot-spot tem peratures are 105, 130, and 180C, respectively. Second, to ascertain whether it i

20、s appropriate to change the present hot-spot temperatures for cer tain applications. It is not the intention at present to use this code to define any new or intermediate insulation temperature glasses. A wide variety of synthetic electrical insulating materials are available for application in elec

21、tric machinery and apparatus. Included in these ma terials are the silicones, fluorocarbons, wire enam els, and new films, rubbers and varnishes. As there is a growing tendency to either rely solely on these materials as electrical insulation, or to employ them with the old familiar materials in nov

22、el combinations, there is a corresponding in crease in the problems associated with the selec tion and evaluation of insulations. Frequently, an insulation “system“ or combination of insulation materials must be evaluated rather than one in sulating “material.“ Many of the specifications regulating

23、the use of insulation materials were written before the ad vent of the newer synthetics and were based upon experience gained with the old materials over a long period of time. Difficulties arise, therefore, when an effort is made to classify these materials or combinations for insulation purposes u

24、nder the American Standards as Class A, Class B, or Class H insulation. The synthetic materials have widely varying properties, so that it is not feasible to classify them on the basis of their chemical composition alone. Secondly, it is not desirable to wait, and acquire the knowledge required to c

25、lassify them solely on the basis of experience. In the third place, composite systems of insulation, in which mate rials of different temperature classes are used in different parts of the structure, may give satis factory service at temperatures higher than nor mally permitted for the lowest temper

26、ature com ponent; and, conversely, compatibility or other problems may arise whereby the highest tempera ture component is rendered unsuitable for use at its classified temperature. Recognizing this situation, this test code has been prepared to outline useful procedures for in sulation evaluation,

27、as a general guide to both tem perature classification and the selection of insul ation materials for application in random-wound rotating elcetric machinery. It is assumed that individual screening tests will eliminate all but the most desirable insulating materials, which will then be evaluated in

28、 accordance with this test code. The code does not cover such special require ments as motors subjected to strong chemicals, to metal dusts, or to submersion in liquids. Methods of Rvaluation.The test code includes three principal sections: 1. Types of insulation specimens that may be properly subje

29、cted to these tests. 2. Temperature, mechanical stress, and moisture exposures that may be applied concurrently, or in sequence to represent the cumulative effects of long service, under accelerated conditions. 3. Magnitudes and durations of test voltages, and other evaluation procedures, that may b

30、e ap plied to the test specimens to measure deteriora tion and to establish the end of useful life. It is recommended that, for each particular kind of insulating material or type of insulating sys tem to be tested, a suitable type of specimen be selected, as outlined in Section 1 of the code. Then,

31、 a number of these specimens, ten for each of the exposure temperatures, be subjected to re peated cycles of the exposures, given in Section 2, in sequence, until failure occurs under the ap plied voltages, as indicated in Section 3 of the code. For each temperature class of insulation, there are gi

32、ven in Section 2 four alternative exposure temperatures, requiring 1, 2, 5, and 8 weeks per test cycle; the temperatures being selected to give roughly the same total number of cycles before failure. Thus, by using the highest tem peratures (1 week per cycle), preliminary tests can be quickly carrie

33、d through; while the lowest 5 temperatures (8 weeks per cycle) must be used for the insulation systems that require thorough evaluation. It is recommended that tests be car ried through for three of these test temperatures for each insulation system to be evaluated. The numbers of cycles to end of l

34、ife for each of the test temperatures are then reported as the final results of all the tests. The ratios of these numbers of cycles to fail ure for the new insulation system, to those for the old system, provide a rough indication of the ratio of the temperature life of the new to that of the old i

35、nsulation system. This procedure will permit approximate com parisons only, and cannot be relied upon to deter mine exactly the merits of any particular insula tion. Such information can only be obtained from extended service experience. In the course of time, however, it is expected that enough dat

36、a may be obtained from tests of this kind to estab lish a normal number of cycles of exposure be fore failure that will be representative of each of the standard temperature classes of insulation A, B and H, for each type of specimen.* It may be feasible to specify the number of cycles before failur

37、e that will be appropriate as indications of satisfactory performance under special service conditions, such as short-time or intermittent and high-temperature exposures. Following the gen eral procedures above outlined, the category in which any new insulating material or system properly belongs ma

38、y be determined. * With such a background of information, it should be pos sible to classify insulation systems on a performance basis. Ultimately, therefore, the definitions of insulating materials may be based on their performance in such tests as these, in stead of solely on their chemical compos

39、ition. Summary.This test code has been prepared in the hope that it will serve as a useful guide for the evaluation of insulation systems for random-wound rotating electric machines, and to estab lish a sound basis for their temperature classifica tion. Once this is accomplished in orderly and organ

40、ized fashion, the problems of insulation selection for use in electric apparatus should be simplified. The code defines test procedures. It does not establish any normal values for insulation life, nor does it provide any standards of performance whatever. SECTION 1 Insulation Test Specimens 1-1 Sco

41、pe.This section suggests appropriate samples of insulating materials or insulating systems, which may be usefully subjected to the exposures outlined in Section 2, to simulate their behavior in service. It is considered that one insulation specimen, as defined in the following, will ade quately repr

42、esent all fractional horsepower motors in the range 0-300 volts, and another will repre sent all integral horsepower random-wound motors of 600 volts or less. Other specimens will be required to represent machines for more than 600 volts, and other than random-wound insul ation. 1-2 Actual Equipment

43、.Whenever economics and/or size of electric equipment warrant, the actual equipment may be employed for test purposes. For example, the complete stator or rotor of an alternating-current fractional horsepower motor is a suitable specimen for the purposes of these tests. 1-3 Model Motors.When size or

44、 convenience re quires that models rather than complete machines be evaluated, the model should be made to em body all of the elements and should be as nearly as possible representative of a complete winding insulation system. For example, it is recommended that for the purposes of testing random-wo

45、und motor insula tion, a “model motor“ be employed, as shown in Figures 1, 2 and 3. Figure 1 shows typical components of a model motor before final assembly. Each of these com ponents should be subjected to separate screen ing tests, to establish uniformity and normality before they are assembled. F

46、or example, a num ber of representative samples of the wire, slot tubes, phase insulation and so forth, may be broken down by 60-cycle high-potential tests, or other means, and the voltage at failure so ob tained may be plotted, to determine the average and standard deviation. It should be recognize

47、d that the number of tests required to establish the acceptable temperature limit in service will in crease greatly, if the performance of individual models varies over a wide range. Further, it must be expected that the variations in the model motors will be directly related to the variations in th

48、e individual components. Therefore, every thing possible should be done to assure that the individual components are uniform and repre sentative of the materials used in actual service. The finished model motor unit consists of a rigid supporting stand with an insulated terminal block bolted to one

49、end and with a slot portion, made from an inner and outer plate, bolted to the other end. The supporting stand has holes for mounting the fixture during vibration testing. All metal parts are fabricated from 0.0625 inch stock. The assembled slot portion contains two coils insulated from ground by slot channels, insulated from each other by phase insulation and held in place with slot wedges. All these components are typical parts used in actual motors, except that the phase insulation shown is shaped so that one piece will suffice for the unit. The coils are each wound with two paralle