欢迎来到麦多课文档分享! | 帮助中心 海量文档,免费浏览,给你所需,享你所想!
麦多课文档分享
全部分类
  • 标准规范>
  • 教学课件>
  • 考试资料>
  • 办公文档>
  • 学术论文>
  • 行业资料>
  • 易语言源码>
  • ImageVerifierCode 换一换
    首页 麦多课文档分享 > 资源分类 > PDF文档下载
    分享到微信 分享到微博 分享到QQ空间

    ANSI ASTM D748-2014 Standard Specification for Natural Block Mica and Mica Films Suitable for Use in Fixed Mica-Dielectric Capacitors.pdf

    • 资源ID:432477       资源大小:225.09KB        全文页数:9页
    • 资源格式: PDF        下载积分:5000积分
    快捷下载 游客一键下载
    账号登录下载
    微信登录下载
    二维码
    微信扫一扫登录
    下载资源需要5000积分(如需开发票,请勿充值!)
    邮箱/手机:
    温馨提示:
    如需开发票,请勿充值!快捷下载时,用户名和密码都是您填写的邮箱或者手机号,方便查询和重复下载(系统自动生成)。
    如需开发票,请勿充值!如填写123,账号就是123,密码也是123。
    支付方式: 支付宝扫码支付    微信扫码支付   
    验证码:   换一换

    加入VIP,交流精品资源
     
    账号:
    密码:
    验证码:   换一换
      忘记密码?
        
    友情提示
    2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网页到桌面,就可以正常下载了。
    3、本站不支持迅雷下载,请使用电脑自带的IE浏览器,或者360浏览器、谷歌浏览器下载即可。
    4、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰。
    5、试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。

    ANSI ASTM D748-2014 Standard Specification for Natural Block Mica and Mica Films Suitable for Use in Fixed Mica-Dielectric Capacitors.pdf

    1、Designation: D748 14Standard Specification forNatural Block Mica and Mica Films Suitable for Use in FixedMica-Dielectric Capacitors1This standard is issued under the fixed designation D748; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev

    2、ision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers natural block mica2and micafilms (cut and uncut) suitable for use in the

    3、 manufacture offixed mica-dielectric capacitors, based on electrical, visual, andphysical properties as determined by tests specified herein.1.2 The values stated in inch-pound units are to be regardedas standard.2. Referenced Documents2.1 ASTM Standards:3D149 Test Method for Dielectric Breakdown Vo

    4、ltage andDielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD351 Classification for Natural Muscovite Block Mica andThins Based on Visual QualityD1082 Test Method for Dissipation Factor and Permittivity(Dielectric Constant) of Mica2.2 ASTM Adjuncts:Test electr

    5、odesGrid test electrodes3. Terminology3.1 For definitions pertaining to this specification see Clas-sification D351.4. Significance and Use4.1 The properties included in this specification are thoserequired to identify the types of natural block mica and micafilms (cut and uncut) suitable for use in

    6、 the manufacture offixed mica-dielectric capacitors. It is possible that other re-quirements will be necessary to identify particular character-istics. These will be added to the specification as their inclusionbecomes generally desirable, and the necessary test data andmethods become available. It

    7、is possible that natural blockmica and mica films that do not conform to the requirements ofthis specification for capacitor use are capable of meeting therequirements for other critical electrical insulation purposes.4.2 The system of classifying electrical quality of naturalblock and mica films (c

    8、ut and uncut) covered by this specifi-cation is based on a combination of electrical and physicalproperties, and visual qualities specified herein, which the micamust possess. This system differs radically from past practicesand previous concepts of mica quality for capacitor use. Theelectrical clas

    9、sification system does not discriminate againstthe presence of spots and stains in even first quality electricallyselected mica, provided the mica conforms to specific andphysical requirements. Appreciable amounts of air inclusionsand waviness also are permitted in all electrical quality classes,pro

    10、vided the mica meets specific electrical and physicalrequirements. Mica meeting these requirements is acceptablewithout regard to color or origin. However, mica meeting theseelectrical and physical requirements but having lower visualquality than that meeting the requirements for the visual qualityc

    11、lassification is not considered generally as desirable.4.3 In capacitor fabrication, one or more pieces of cut filmor block mica having lower than required electrical andphysical properties will possibly prevent meeting the endrequirements of the capacitor. It is therefore required that eachpiece of

    12、 block (cut) or film (cut or uncut), or both, be tested forthe electrical requirements and inspected for the visual require-ments listed in this specification.5. Forms5.1 This specification covers the following three forms ofnatural mica, suitable for use in the manufacture of mica-dielectric capaci

    13、tors:5.1.1 Form 1Full-knife trimmed natural block mica 0.007to 0.035 in. (0.18 to 0.89 mm) in thickness.5.1.1.1 It is acceptable for a certain percentage of blockmica thinner than 0.007 in. to be accepted under thisspecification, upon agreement between the purchaser and themanufacturer.1This specifi

    14、cation is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Products.Current edition approved Nov. 1, 2014. Published December 2014. Originallyapproved in 1943. Last previous e

    15、dition approved in 2011 as D748 00 (2011).DOI: 10.1520/D0748-14.2Coutlee, K. G., “Electrical Quality Classification of Raw Mica by a Rapid,Direct-Reading Test Method,” Proceedings, ASTM, Vol 46, 1946, p. 1486.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom

    16、er Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA

    17、 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization T

    18、echnical Barriers to Trade (TBT) Committee.15.1.2 Form 2Half-knife trimmed natural block mica 0.007to 0.035 in. in thickness.5.1.3 Form 3Films (cut or uncut) split or manufacturedfrom natural block mica in any range from 0.0008 up to andincluding 0.006 in. (0.020 to 0.15 mm).6. Grades (Sizes)6.1 For

    19、 grades see Classification D351.7. Classes7.1 This specification covers the following four classes andsubdivisions of natural block mica or mica films. The class ofmica desired shall be specified by the purchaser. Block mica ormica films shall conform to all of the requirements of itsrespective clas

    20、s, unless otherwise specified by the purchaser.7.1.1 Class C-1 SpecialClass C-1 special mica films, inaddition to having the highest Q obtainable for mica in themegacycle range, also have the highest Q generally obtainablefor mica in the audio frequency range (1000 min at 1 kHz).Such mica therefore

    21、is particularly suitable for capacitorswhich must meet highest Q requirements at both high and lowfrequencies.7.1.2 Class C-1Class C-1 block mica or mica films havethe highest Q value obtainable for mica (2500 min at 1 MHz incapacitors) and are suitable for use in all sizes and types ofsilver and fo

    22、il electrode, molded and clamped unit capacitors,including the most critical types, for use in high stability tunedcircuits, as well as high current radio frequency capacitors usedin radio transmitter circuits.NOTE 1Based4on commercial experience Class C-1 block mica ormica films are satisfactory fo

    23、r the manufacture of all of these types of micacapacitors. However, it has been found that some “medium to heavy”air-stained mica will produce a slightly lower yield of highest stability andhigh current radio frequency types of capacitors, as well as a somewhatlower yield of satisfactory silver elec

    24、trode mica laminations. Likewise, itis also possible that some “medium to heavy” wavy mica will alsoadversely influence the application of silver electrodes. In addition, thereis some possibility that excessive waviness will cause cracked laminationsin molded capacitors due to the high molding press

    25、ures employed, thusmaking it less suitable from a stacking standpoint. Similarly, excessiveamounts of either air inclusions or waviness could cause some reductionin unit volume capacitance of foil electrode capacitors.7.1.3 Class C-2Class C-2 block mica and mica films havea high order of Q value (15

    26、00 min at 1 MHz in capacitors) andare suitable for use in all sizes and types of silver and foilelectrode molded and clamped unit capacitors similar to thosespecified for Class C-1 mica. However, a certain percentage ofcapacitors made with Class C-2 block mica and films mayshow a somewhat higher tem

    27、perature rise in transmitter typesthan capacitors made with Class C-1 block mica or mica films.7.1.4 Class C-3Class C-3 block mica and mica films havethe lowest Q value (200 min at 1 MHz in capacitors) of thethree classes covered by this specification. Such Q value,however, is sufficiently high to p

    28、ermit this mica to be classedas a low-loss insulating material. This mica is particularlysuitable for use in foil electrode molded and clamped typecapacitors (Note 2) used in less critical circuits for blockingand coupling purposes where high Q value, high stability, andlow temperature coefficient a

    29、re not required.NOTE 2Experience has shown that silver electrode molded capacitorsmade with Class C-3 mica, which contained slightly conducting spots andstains but contained “very slight” air inclusions and “nearly flat” waves,had temperature coefficient and capacitance stability characteristics jus

    30、t asgood as that obtained with capacitors made with the best Class C-1 mica.8. Electrical and Physical Properties, and VisualQualities8.1 Natural block mica and mica films shall conform to therequirements as to electrical and physical properties and visualqualities as prescribed in Table 1. Visual q

    31、ualities not coveredin this specification are permitted provided mica meets theelectrical and physical requirements.9. Test Methods9.1 The properties enumerated in this specification shall bedetermined in accordance with the following:9.2 Grading According to SizeClassification D351.9.3 Electrical C

    32、onductivitySee Annex A1.NOTE 3For the purpose of this specification, electrical conductivity inspotted and stained areas of block mica is revealed when visible sparkingor glowing takes place inside or on the surface of the mica in the vicinityof the test probe, and not by actual puncture of the mica

    33、 by thehigh-potential current. If actual puncture of the test specimen does takeplace this indicates the presence of mechanical faults, such as pinholes,tears, or cracks which extend completely through the mica. While this testmethod had been found suitable for controlling conductivity in spots ands

    34、tains and dielectric weakness due to mechanical faults in block mica, aneven greater factor of safety will be realized if this flash test is applieddirectly to capacitor films. In this instance the purpose of the test is todetect dielectric weakness due to any cause.9.4 Q Value or Dissipation Factor

    35、Test Method D1082 at1 MHz, or by the rapid, direct-reading method described inAppendix X1.NOTE 4In cases of dispute arising from borderline cases of Q value ordissipation factor and dielectric strength, the test specimens shall be bakedfor a minimum period of2hatatemperature of 121C (250F), and test

    36、edimmediately upon cooling to room temperature.9.5 Dielectric StrengthTest Method D149,usingtheshort-time test with14-in. (6.4-mm) diameter electrodes in oil.9.6 Weight Loss on HeatingPreheat the test specimens inan oven at 121C (250F) for a minimum time of 2 h and thenweigh. Then heat the specimens

    37、 in the oven at 600C (1110F)for 5 min and reweigh. Calculate the percentage loss in weightafter heating based on the weight of the specimen at the end ofthe 2-h preheating period.9.7 Thickness Uniformity (Films)Judge splitting qualityby the uniformity of thickness of films split from mica byviewing

    38、between crossed polaroids.9.8 Visual QualitiesSee Classification D351.9.8.1 Air InclusionsReflected daylight or equivalent.9.8.2 Waves, Buckles, Ridges, and so forthReflected day-light or its equivalent where distortion of parallel and verticallines of reflected image, such as a window frame, can be

    39、judged.4Coutlee, K. G., “Judging Mica Quality Electrically,” Transactions, Am. Inst.Electrical Engrs., Vol 64, 1945.D748 1429.8.3 Cracks, Tears, Pinholes, and StonesDetermine thepresence of such mechanical defects as cracks, tears, pinholes,and stones by the spark coil test as prescribed in Annex A1

    40、,orby visual inspection as judged by transmitted daylight or itsequivalent.10. Precision and Bias10.1 This test method has been in use for many years, but noinformation has been presented to ASTM upon which to basea statement of precision or bias. No activity has been plannedto develop such informat

    41、ion.11. Keywords11.1 block mica; capacitor; classes; dielectric strength; elec-trical conductivity; form; grades; mica; mica films; Q value;visual quality; weight lossTABLE 1 Electrical, Physical, and Visual Quality Requirements of Natural Block Mica and Mica Films for Use in CapacitorsClass C-1 Cla

    42、ss C-2 Class C-3Electrical Properties:Conducting pathsAnone none noneQ value or dissipation factor at 1 MHz E-1BE-2BE-3BDielectric strength, minV/mil at 60 HzHaveragesingle100085010008501000850Dielectric constantCCCPhysical Properties:Weight loss on heating (5 min at 600 C), max % 0.2 0.2 0.2Thickne

    43、ss uniformity (mica films)Dbest best intermediateTemperature coefficient of capacitance and retraceEEVisual Qualities:FAirinclusionsGHABCvery slightHslightImediumJvery slightHslightFmediumJvery slightHslightImediumJWavesK5ABCDnearlyflatslightmediumheavynearlyflatslightmediumheavynearlyflatslightmedi

    44、umheavyCracks none none noneTears none none nonePin holes none none noneStones none none noneBuckles none none noneRidges none none noneAThis applies to the conductivity of visible spots and stains only and excludes air stains or air inclusions.BThe Q values or dissipation factor Q5S1dissipation fac

    45、torDof block mica or mica films suitable for use in capacitors shall fall within specified electrical quality groups,based on end-use requirements, designated E-1 Special, E-1, E-2, or E-3. These quality groups shall conform to the Q or dissipation factor values prescribed in Table 2or the correspon

    46、ding scale readings of the vacuum-tube voltmeter when tested by the rapid, direct-reading method described in Appendix X1.CAs the dielectric constant of natural block mica suitable for use in capacitors is fairly uniform, no value is specified.DUntil definite values can be specified, the permissible

    47、 amounts of such defects shall be agreed upon between the purchaser and the manufacturer.EIt has been found that the temperature coefficient of capacitance and retrace of capacitors made with Classes C-1, C-2, and C-3 mica are more dependent on such factorsas electrical and mechanical design and man

    48、ufacturing technique than on any differences in the mica itself.FSee Classification D351.GThe amount of air inclusions shall not exceed the specified limits for each subclass. The permissible amount of air inclusions shall be stated by suffixing the appropriateletter (in other words, either A, B, C,

    49、 or D) to the required electrical quality class.HFew and tiny in one fourth of usable area (must not contain air chains, and so forth).IIn one half of usable area (must not contain air chains, and so forth).JIn two thirds of usable areas.KThe waviness shall not exceed the specified limits for each subclass. The permissible amount of waves shall be stated by suffixing the appropriate letter (in other words,either A, B, C or D) to the letter denoting the amount of permissible air inclusions. For example, Class C-1 B A block mica or mica films denotes:C-1


    注意事项

    本文(ANSI ASTM D748-2014 Standard Specification for Natural Block Mica and Mica Films Suitable for Use in Fixed Mica-Dielectric Capacitors.pdf)为本站会员(amazingpat195)主动上传,麦多课文档分享仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知麦多课文档分享(点击联系客服),我们立即给予删除!




    关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

    copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
    备案/许可证编号:苏ICP备17064731号-1 

    收起
    展开