Neets v04-conductors

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Neets v04-conductors

  1. 1. NONRESIDENT TRAINING COURSE SEPTEMBER 1998Navy Electricity andElectronics Training SeriesModule 4—Introduction to ElectricalConductors, Wiring Techniques, andSchematic ReadingNAVEDTRA 14176 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
  2. 2. Although the words “he,” “him,” and “his” are used sparingly in this course to enhance communication, they are not intended to be gender driven or to affront or discriminate against anyone.DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
  3. 3. PREFACEBy enrolling in this self-study course, you have demonstrated a desire to improve yourself and the Navy.Remember, however, this self-study course is only one part of the total Navy training program. Practicalexperience, schools, selected reading, and your desire to succeed are also necessary to successfully roundout a fully meaningful training program.COURSE OVERVIEW: To introduce the student to the subject of Electrical Conductors, WiringTechniques, and Schematic Reading who needs such a background in accomplishing daily work and/or inpreparing for further study.THE COURSE: This self-study course is organized into subject matter areas, each containing learningobjectives to help you determine what you should learn along with text and illustrations to help youunderstand the information. The subject matter reflects day-to-day requirements and experiences ofpersonnel in the rating or skill area. It also reflects guidance provided by Enlisted Community Managers(ECMs) and other senior personnel, technical references, instructions, etc., and either the occupational ornaval standards, which are listed in the Manual of Navy Enlisted Manpower Personnel Classificationsand Occupational Standards, NAVPERS 18068.THE QUESTIONS: The questions that appear in this course are designed to help you understand thematerial in the text.VALUE: In completing this course, you will improve your military and professional knowledge.Importantly, it can also help you study for the Navy-wide advancement in rate examination. If you arestudying and discover a reference in the text to another publication for further information, look it up. 1998 Edition Prepared by AECS Steve Heartsfield Published by NAVAL EDUCATION AND TRAINING PROFESSIONAL DEVELOPMENT AND TECHNOLOGY CENTER NAVSUP Logistics Tracking Number 0504-LP-026-8290 i
  4. 4. Sailor’s Creed“I am a United States Sailor.I will support and defend theConstitution of the United States ofAmerica and I will obey the ordersof those appointed over me.I represent the fighting spirit of theNavy and those who have gonebefore me to defend freedom anddemocracy around the world.I proudly serve my country’s Navycombat team with honor, courageand commitment.I am committed to excellence andthe fair treatment of all.” ii
  5. 5. TABLE OF CONTENTSCHAPTER PAGE 1. Electrical Conductors ............................................................................................... 1-1 2. Wiring Techniques ................................................................................................... 2-1 3. Schematic Reading ................................................................................................... 3-1APPENDIX I. Glossary.................................................................................................................. AI-1 II. Electrical and electronic Symbols .......................................................................... AII-1 III. References Used to Develop The Training Manual ............................................... AIII-1INDEX ......................................................................................................................... INDEX-1 iii
  6. 6. NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIESThe Navy Electricity and Electronics Training Series (NEETS) was developed for use by personnel inmany electrical- and electronic-related Navy ratings. Written by, and with the advice of, seniortechnicians in these ratings, this series provides beginners with fundamental electrical and electronicconcepts through self-study. The presentation of this series is not oriented to any specific rating structure,but is divided into modules containing related information organized into traditional paths of instruction.The series is designed to give small amounts of information that can be easily digested before advancingfurther into the more complex material. For a student just becoming acquainted with electricity orelectronics, it is highly recommended that the modules be studied in their suggested sequence. Whilethere is a listing of NEETS by module title, the following brief descriptions give a quick overview of howthe individual modules flow together.Module 1, Introduction to Matter, Energy, and Direct Current, introduces the course with a short historyof electricity and electronics and proceeds into the characteristics of matter, energy, and direct current(dc). It also describes some of the general safety precautions and first-aid procedures that should becommon knowledge for a person working in the field of electricity. Related safety hints are locatedthroughout the rest of the series, as well.Module 2, Introduction to Alternating Current and Transformers, is an introduction to alternating current(ac) and transformers, including basic ac theory and fundamentals of electromagnetism, inductance,capacitance, impedance, and transformers.Module 3, Introduction to Circuit Protection, Control, and Measurement, encompasses circuit breakers,fuses, and current limiters used in circuit protection, as well as the theory and use of meters as electricalmeasuring devices.Module 4, Introduction to Electrical Conductors, Wiring Techniques, and Schematic Reading, presentsconductor usage, insulation used as wire covering, splicing, termination of wiring, soldering, and readingelectrical wiring diagrams.Module 5, Introduction to Generators and Motors, is an introduction to generators and motors, andcovers the uses of ac and dc generators and motors in the conversion of electrical and mechanicalenergies.Module 6, Introduction to Electronic Emission, Tubes, and Power Supplies, ties the first five modulestogether in an introduction to vacuum tubes and vacuum-tube power supplies.Module 7, Introduction to Solid-State Devices and Power Supplies, is similar to module 6, but it is inreference to solid-state devices.Module 8, Introduction to Amplifiers, covers amplifiers.Module 9, Introduction to Wave-Generation and Wave-Shaping Circuits, discusses wave generation andwave-shaping circuits.Module 10, Introduction to Wave Propagation, Transmission Lines, and Antennas, presents thecharacteristics of wave propagation, transmission lines, and antennas. iv
  7. 7. Module 11, Microwave Principles, explains microwave oscillators, amplifiers, and waveguides.Module 12, Modulation Principles, discusses the principles of modulation.Module 13, Introduction to Number Systems and Logic Circuits, presents the fundamental concepts ofnumber systems, Boolean algebra, and logic circuits, all of which pertain to digital computers.Module 14, Introduction to Microelectronics, covers microelectronics technology and miniature andmicrominiature circuit repair.Module 15, Principles of Synchros, Servos, and Gyros, provides the basic principles, operations,functions, and applications of synchro, servo, and gyro mechanisms.Module 16, Introduction to Test Equipment, is an introduction to some of the more commonly used testequipments and their applications.Module 17, Radio-Frequency Communications Principles, presents the fundamentals of a radio-frequency communications system.Module 18, Radar Principles, covers the fundamentals of a radar system.Module 19, The Technicians Handbook, is a handy reference of commonly used general information,such as electrical and electronic formulas, color coding, and naval supply system data.Module 20, Master Glossary, is the glossary of terms for the series.Module 21, Test Methods and Practices, describes basic test methods and practices.Module 22, Introduction to Digital Computers, is an introduction to digital computers.Module 23, Magnetic Recording, is an introduction to the use and maintenance of magnetic recorders andthe concepts of recording on magnetic tape and disks.Module 24, Introduction to Fiber Optics, is an introduction to fiber optics.Embedded questions are inserted throughout each module, except for modules 19 and 20, which arereference books. If you have any difficulty in answering any of the questions, restudy the applicablesection.Although an attempt has been made to use simple language, various technical words and phrases havenecessarily been included. Specific terms are defined in Module 20, Master Glossary.Considerable emphasis has been placed on illustrations to provide a maximum amount of information. Insome instances, a knowledge of basic algebra may be required.Assignments are provided for each module, with the exceptions of Module 19, The TechniciansHandbook; and Module 20, Master Glossary. Course descriptions and ordering information are inNAVEDTRA 12061, Catalog of Nonresident Training Courses. v
  8. 8. Throughout the text of this course and while using technical manuals associated with the equipment youwill be working on, you will find the below notations at the end of some paragraphs. The notations areused to emphasize that safety hazards exist and care must be taken or observed. WARNING AN OPERATING PROCEDURE, PRACTICE, OR CONDITION, ETC., WHICH MAY RESULT IN INJURY OR DEATH IF NOT CAREFULLY OBSERVED OR FOLLOWED. CAUTION AN OPERATING PROCEDURE, PRACTICE, OR CONDITION, ETC., WHICH MAY RESULT IN DAMAGE TO EQUIPMENT IF NOT CAREFULLY OBSERVED OR FOLLOWED. NOTE An operating procedure, practice, or condition, etc., which is essential to emphasize. vi
  9. 9. INSTRUCTIONS FOR TAKING THE COURSEASSIGNMENTS assignments. To submit your assignment answers via the Internet, go to:The text pages that you are to study are listed atthe beginning of each assignment. Study these http://courses.cnet.navy.milpages carefully before attempting to answer thequestions. Pay close attention to tables and Grading by Mail: When you submit answerillustrations and read the learning objectives. sheets by mail, send all of your assignments atThe learning objectives state what you should be one time. Do NOT submit individual answerable to do after studying the material. Answering sheets for grading. Mail all of your assignmentsthe questions correctly helps you accomplish the in an envelope, which you either provideobjectives. yourself or obtain from your nearest Educational Services Officer (ESO). Submit answer sheetsSELECTING YOUR ANSWERS to:Read each question carefully, then select the COMMANDING OFFICERBEST answer. You may refer freely to the text. NETPDTC N331The answers must be the result of your own 6490 SAUFLEY FIELD ROADwork and decisions. You are prohibited from PENSACOLA FL 32559-5000referring to or copying the answers of others andfrom giving answers to anyone else taking the Answer Sheets: All courses include onecourse. “scannable” answer sheet for each assignment. These answer sheets are preprinted with yourSUBMITTING YOUR ASSIGNMENTS SSN, name, assignment number, and course number. Explanations for completing the answerTo have your assignments graded, you must be sheets are on the answer sheet.enrolled in the course with the NonresidentTraining Course Administration Branch at the Do not use answer sheet reproductions: UseNaval Education and Training Professional only the original answer sheets that weDevelopment and Technology Center provide—reproductions will not work with our(NETPDTC). Following enrollment, there are scanning equipment and cannot be processed.two ways of having your assignments graded:(1) use the Internet to submit your assignments Follow the instructions for marking youras you complete them, or (2) send all the answers on the answer sheet. Be sure that blocksassignments at one time by mail to NETPDTC. 1, 2, and 3 are filled in correctly. This information is necessary for your course to beGrading on the Internet: Advantages to properly processed and for you to receive creditInternet grading are: for your work.• you may submit your answers as soon as COMPLETION TIME you complete an assignment, and• you get your results faster; usually by the Courses must be completed within 12 months next working day (approximately 24 hours). from the date of enrollment. This includes time required to resubmit failed assignments.In addition to receiving grade results for eachassignment, you will receive course completionconfirmation once you have completed all the vii
  10. 10. PASS/FAIL ASSIGNMENT PROCEDURES For subject matter questions:If your overall course score is 3.2 or higher, you E-mail: n315.products@cnet.navy.milwill pass the course and will not be required to Phone: Comm: (850) 452-1001, ext. 1728resubmit assignments. Once your assignments DSN: 922-1001, ext. 1728have been graded you will receive course FAX: (850) 452-1370completion confirmation. (Do not fax answer sheets.) Address: COMMANDING OFFICERIf you receive less than a 3.2 on any assignment NETPDTC N315and your overall course score is below 3.2, you 6490 SAUFLEY FIELD ROADwill be given the opportunity to resubmit failed PENSACOLA FL 32509-5237assignments. You may resubmit failedassignments only once. Internet students will For enrollment, shipping, grading, orreceive notification when they have failed an completion letter questionsassignment--they may then resubmit failedassignments on the web site. Internet students E-mail: fleetservices@cnet.navy.milmay view and print results for failed Phone: Toll Free: 877-264-8583assignments from the web site. Students who Comm: (850) 452-1511/1181/1859submit by mail will receive a failing result letter DSN: 922-1511/1181/1859and a new answer sheet for resubmission of each FAX: (850) 452-1370failed assignment. (Do not fax answer sheets.) Address: COMMANDING OFFICERCOMPLETION CONFIRMATION NETPDTC N331 6490 SAUFLEY FIELD ROADAfter successfully completing this course, you PENSACOLA FL 32559-5000will receive a letter of completion. NAVAL RESERVE RETIREMENT CREDITERRATA If you are a member of the Naval Reserve, youErrata are used to correct minor errors or delete will receive retirement points if you areobsolete information in a course. Errata may authorized to receive them under currentalso be used to provide instructions to the directives governing retirement of Navalstudent. If a course has an errata, it will be Reserve personnel. For Naval Reserveincluded as the first page(s) after the front cover. retirement, this course is evaluated at 3 points.Errata for all courses can be accessed and (Refer to Administrative Procedures for Navalviewed/downloaded at: Reservists on Inactive Duty, BUPERSINST 1001.39, for more information about retirementhttp://www.advancement.cnet.navy.mil points.)STUDENT FEEDBACK QUESTIONSWe value your suggestions, questions, andcriticisms on our courses. If you would like tocommunicate with us regarding this course, weencourage you, if possible, to use e-mail. If youwrite or fax, please use a copy of the StudentComment form that follows this page. viii
  11. 11. Student Comments NEETS Module 4 Introduction to Electrical Conductors, Wiring Techniques, and SchematicCourse Title: ReadingNAVEDTRA: 14176 Date:We need some information about you:Rate/Rank and Name: SSN: Command/UnitStreet Address: City: State/FPO: ZipYour comments, suggestions, etc.:Privacy Act Statement: Under authority of Title 5, USC 301, information regarding your military status isrequested in processing your comments and in preparing a reply. This information will not be divulged withoutwritten authorization to anyone other than those within DOD for official use in determining performance.NETPDTC 1550/41 (Rev 4-00) ix
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  55. 55. Table 1-2.—Standard Solid Copper (American Wire Gauge) *DJH LDPHWHU URVV 6HFWLRQ 2KPV SHU IW 2KPV SHU 3RXQGV SHUQXPEHU PLOV
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  60. 60. LV XVHG WR PHDVXUH ZLUHV UDQJLQJ LQ VL]H IURPQXPEHU WR QXPEHU 7R XVH WKLV JDXJH LQVHUW WKH ZLUH WR EH PHDVXUHG LQWR WKH VPDOOHVW VORW WKDW ZLOOMXVW DFFRPPRGDWH WKH EDUH ZLUH 7KH JDXJH QXPEHU RQ WKDW VORW LQGLFDWHV WKH ZLUH VL]H 7KH IURQW SDUW RIWKH VORW KDV SDUDOOHO VLGHV DQG WKLV LV ZKHUH WKH ZLUH PHDVXUHPHQW LV WDNHQ ,W VKRXOG QRW EH FRQIXVHG ZLWKWKH ODUJHU VHPLFLUFXODU RSHQLQJ DW WKH UHDU RI WKH VORW 7KH UHDU RSHQLQJ VLPSO SHUPLWV WKH IUHH PRYHPHQWRI WKH ZLUH DOO WKH ZD WKURXJK WKH VORW Figure 1-4.—Wire gauge. Q9. Using table 1-2, determine the resistance of 1,500 feet of AWG 20 wire at 25º C. Q10. When using an American Standard Wire Gauge to determine the size of a wire, where should you place the wire in the gauge to get the correct measurement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  65. 65. Figure 1-5.—Conductors. RQGXFWRUV DUH VWUDQGHG PDLQO WR LQFUHDVH WKHLU IOH[LELOLW 7KH ZLUH VWUDQGV LQ FDEOHV DUH DUUDQJHGLQ WKH IROORZLQJ RUGHU 7KH ILUVW ODHU RI VWUDQGV DURXQG WKH FHQWHU FRQGXFWRU LV PDGH XS RI VL[ FRQGXFWRUV 7KH VHFRQG ODHULV PDGH XS RI DGGLWLRQDO FRQGXFWRUV 7KH WKLUG ODHU LV PDGH XS RI DGGLWLRQDO FRQGXFWRUV DQG VR RQ7KXV VWDQGDUG FDEOHV DUH FRPSRVHG RI DQG VWUDQGV LQ FRQWLQXLQJ IL[HG LQFUHPHQWV 7KH RYHUDOOIOH[LELOLW FDQ EH LQFUHDVHG E IXUWKHU VWUDQGLQJ RI WKH LQGLYLGXDO VWUDQGV )LJXUH VKRZV D WSLFDO FURVV VHFWLRQ RI D VWUDQG FDEOH ,W DOVR VKRZV KRZ WKH WRWDO FLUFXODUPLOFURVVVHFWLRQDO DUHD RI D VWUDQGHG FDEOH LV GHWHUPLQHG Figure 1-6.—Stranded conductor.
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  69. 69. VLOLFRQH UXEEHU RU H[WUXGHG SROWHWUDIOXRURHWKOHQH 7KH DUH HIIHFWLYH DW VWLOOKLJKHU WHPSHUDWXUHVSAFE CURRENT RATINGS 7KH 1DWLRQDO %RDUG RI )LUH 8QGHUZULWHUV SUHSDUHV WDEOHV VKRZLQJ WKH VDIH FXUUHQW UDWLQJV IRU VL]HVDQG WSHV RI FRQGXFWRUV FRYHUHG ZLWK YDULRXV WSHV RI LQVXODWLRQ 7KH DOORZDEOH FXUUHQWFDUULQJFDSDFLWLHV RI VLQJOH FRSSHU FRQGXFWRUV LQ IUHH DLU DW D PD[LPXP URRP WHPSHUDWXUH RI ž ž )
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  71. 71. Q11. List the four factors you should use to select wire for a specified current rating. Q12. What are three types of nonmetallic insulating materials that can be used in a high-temperature environments? Q13. State why it is important for you to consider the ambient (surrounding) temperature of a conductor when selecting wire size. COPPER-VERSUS-ALUMINUM CONDUCTORS $OWKRXJK VLOYHU LV WKH EHVW FRQGXFWRU LWV FRVW OLPLWV LWV XVH WR VSHFLDO FLUFXLWV 6LOYHU LV XVHG ZKHUH DVXEVWDQFH ZLWK KLJK FRQGXFWLYLW RU ORZ UHVLVWLYLW LV QHHGHG 7KH WZR PRVW FRPPRQO XVHG FRQGXFWRUV DUH FRSSHU DQG DOXPLQXP (DFK KDV SRVLWLYH DQG QHJDWLYHFKDUDFWHULVWLFV WKDW DIIHFW LWV XVH XQGHU YDULQJ FLUFXPVWDQFHV $ FRPSDULVRQ RI VRPH RI WKHFKDUDFWHULVWLFV RI FRSSHU DQG DOXPLQXP LV JLYHQ LQ WDEOH
  72. 72. Table 1-4.—Comparative Characteristics of Copper and Aluminum +$5$7(5,67,6 233(5 $/80,180 7HQVLOH VWUHQJWK OELQ
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  82. 82. DUHLQVXODWLRQ UHVLVWDQFH DQG GLHOHFWULF VWUHQJWK 7KHVH DUH WZR HQWLUHO GLIIHUHQW DQG GLVWLQFW SURSHUWLHVINSULATION RESISTANCE ,QVXODWLRQ UHVLVWDQFH LV WKH UHVLVWDQFH WR FXUUHQW OHDNDJH WKURXJK WKH LQVXODWLRQ PDWHULDOV ,QVXODWLRQUHVLVWDQFH FDQ EH PHDVXUHG ZLWK D PHJJHU ZLWKRXW GDPDJLQJ WKH LQVXODWLRQ ,QIRUPDWLRQ VR REWDLQHG LV DXVHIXO JXLGH LQ DSSUDLVLQJ WKH JHQHUDO FRQGLWLRQ RI LQVXODWLRQ OHDQ GU LQVXODWLRQ KDYLQJ FUDFNV RU RWKHUIDXOWV PD VKRZ D KLJK YDOXH RI LQVXODWLRQ UHVLVWDQFH EXW ZRXOG QRW EH VXLWDEOH IRU XVHDIELECTRIC STRENGTH LHOHFWULF VWUHQJWK LV WKH DELOLW RI DQ LQVXODWRU WR ZLWKVWDQG SRWHQWLDO GLIIHUHQFH ,W LV XVXDOOH[SUHVVHG LQ WHUPV RI WKH YROWDJH DW ZKLFK WKH LQVXODWLRQ IDLOV EHFDXVH RI WKH HOHFWURVWDWLF VWUHVV0D[LPXP GLHOHFWULF VWUHQJWK YDOXHV FDQ EH PHDVXUHG RQO E UDLVLQJ WKH YROWDJH RI D 7(67 6$03/(XQWLO WKH LQVXODWLRQ EUHDNV GRZQ Q18. Compare the resistance of a conductor to that of an insulator. Q19. State two fundamental properties of insulating materials. Q20. Define insulation resistance. Q21. Define dielectric strength. Q22. How is the dielectric strength of an insulator determined?TYPES OF INSULATION 7KH LQVXODWLQJ PDWHULDOV GLVFXVVHG LQ WKH QH[W SDUDJUDSKV DUH FRPPRQO XVHG LQ 1DY HOHFWULFDO DQGHOHFWURQLF HTXLSPHQWRubber 2QH RI WKH PRVW FRPPRQ WSHV RI LQVXODWLRQ LV UXEEHU 7KH YROWDJH WKDW PD EH DSSOLHG WR D UXEEHUFRYHUHG FRQGXFWRU LV GHSHQGHQW RQ WKH WKLFNQHVV DQG WKH TXDOLW RI WKH UXEEHU FRYHULQJ 2WKHU IDFWRUVEHLQJ HTXDO WKH WKLFNHU WKH LQVXODWLRQ WKH KLJKHU PD EH WKH DSSOLHG YROWDJH 5XEEHU LQVXODWLRQ LVQRUPDOO XVHG IRU ORZ RU PHGLXPUDQJH YROWDJH )LJXUH VKRZV WZR WSHV RI UXEEHUFRYHUHG ZLUH2QH LV D WZRFRQGXFWRU FDEOH LQ ZKLFK HDFK VWUDQGHG FRQGXFWRU LV FRYHUHG ZLWK UXEEHU LQVXODWLRQ WKHRWKHU LV D VLQJOH VROLG FRQGXFWRU ,Q HDFK FDVH WKH UXEEHU VHUYHV WKH VDPH SXUSRVH WR FRQILQH WKH FXUUHQWWR LWV FRQGXFWRU
  83. 83. Figure 1-7.—Rubber insulation. 5HIHUULQJ WR WKH HQODUJHG FURVVVHFWLRQDO YLHZ LQ ILJXUH QRWH WKDW D WKLQ FRDWLQJ RI WLQ VHSDUDWHVWKH FRSSHU FRQGXFWRU IURP WKH UXEEHU LQVXODWLRQ ,I WKH WKLQ FRDWLQJ RI WLQ ZHUH QRW XVHG D FKHPLFDO DFWLRQZRXOG WDNH SODFH DQG WKH UXEEHU ZRXOG EHFRPH VRIW DQG JXPP ZKHUH LW PDNHV FRQWDFW ZLWK WKH FRSSHU:KHQ VPDOO VROLG RU VWUDQGHG FRQGXFWRUV DUH XVHG D ZLQGLQJ RI FRWWRQ WKUHDGV LV DSSOLHG EHWZHHQ WKHFRQGXFWRUV DQG WKH UXEEHU LQVXODWLRQ CODE-GRADED RUBBER²RGHJUDGHG UXEEHU LV WKH VWDQGDUG WKDW WKH 1DWLRQDO (OHFWULFDORGH 1(
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  87. 87. ,Q 7SH 6$ WKH LQVXODWRU DURXQG WKHFRQGXFWRU LV VLOLFRQH UXEEHU EXW WKH RXWHU FRYHULQJ PXVW FRQVLVW RI KHDY JODVV DVEHVWRVJODVV RUDVEHVWRV EUDLGLQJ WUHDWHG ZLWK D KHDW IODPH DQG PRLVWXUHUHVLVWDQW FRPSRXQG Q23. What is the purpose of coating a copper conductor with tin when rubber insulation is used?
  88. 88. Plastics 3ODVWLF LV RQH RI WKH PRUH FRPPRQO XVHG WSHV RI LQVXODWLQJ PDWHULDO IRU HOHFWULFDO FRQGXFWRUV ,W KDVJRRG LQVXODWLQJ IOH[LELOLW DQG PRLVWXUHUHVLVWDQW TXDOLWLHV $OWKRXJK WKHUH DUH PDQ WSHV RI SODVWLFLQVXODWLQJ PDWHULDOV WKHUPRSODVWLF LV RQH RI WKH PRVW FRPPRQ :LWK WKH XVH RI WKHUPRSODVWLF WKHFRQGXFWRU WHPSHUDWXUH FDQ EH KLJKHU WKDQ ZLWK VRPH RWKHU WSHV RI LQVXODWLQJ PDWHULDOV ZLWKRXW GDPDJHWR WKH LQVXODWLQJ TXDOLW RI WKH PDWHULDO 3ODVWLF LQVXODWLRQ LV QRUPDOO XVHG IRU ORZ RU PHGLXPUDQJHYROWDJH 7KH GHVLJQDWRUV XVHG ZLWK WKHUPRSODVWLFV DUH PXFK OLNH WKRVH XVHG ZLWK UXEEHU LQVXODWRUV 7KHIROORZLQJ OHWWHUV DUH XVHG ZKHQ GHDOLQJ ZLWK 1( WSH GHVLJQDWRUV IRU WKHUPRSODVWLFV /HWWHU HVLJQDWHV 7 7KHUPRSODVWLF + +HDWUHVLVWDQW : 0RLVWXUHUHVLVWDQW $ $VEHVWRV 1 2XWHU QORQ MDFNHW 0 2LOUHVLVWDQW )RU H[DPSOH D 1( GHVLJQDWRU RI 7SH 7+:1 ZRXOG LQGLFDWH WKHUPRSODVWLF KHDW DQG PRLVWXUHUHVLVWDQW ZLWK DQ RXWHU QORQ MDFNHWVarnished Cambric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igure 1-8.—Varnished cambric insulation. DPEULF LQVXODWLRQ LV XVHG RQ H[WUHPHO KLJKYROWDJH FRQGXFWRUV XVHG LQ VXEVWDWLRQV DQGSRZHUKRXVHV ,W LV DOVR XVHG LQ RWKHU ORFDWLRQV VXEMHFWHG WR KLJK WHPSHUDWXUHV ,Q DGGLWLRQ LW LV XVHG RQ WKHFRLOV DQG OHDGV RI KLJKYROWDJH JHQHUDWRUV 7UDQVIRUPHU OHDGV DOVR XVH WKLV LQVXODWLRQ EHFDXVH LW LVXQDIIHFWHG E RLOV RU JUHDVH DQG KDV KLJK GLHOHFWULF VWUHQJWK 9DUQLVKHG FDPEULF DQG SDSHU LQVXODWLRQ IRUFDEOHV DUH WKH WZR WSHV RI LQVXODWLQJ PDWHULDOV PRVW ZLGHO XVHG DW YROWDJHV DERYH YROWV 6XFKFDEOH LV DOZDV OHDG FRYHUHG WR NHHS RXW PRLVWXUH
  89. 89. Extruded Polytetrafluoroethylene ([WUXGHG SROWHWUDIOXRURHWKOHQH LV D KLJKWHPSHUDWXUH LQVXODWLRQ XVHG H[WHQVLYHO LQ DLUFUDIW DQGHTXLSPHQW LQVWDOODWLRQV ,W ZLOO QRW EXUQ EXW ZLOO YDSRUL]H ZKHQ VXEMHFWHG WR LQWHQVH KHDW RQGXFWRUV IRUKLJK WHPSHUDWXUHV XVH D QLFNHO FRDWLQJ UDWKHU WKDQ WLQ RU VLOYHU WR SUHYHQW R[LGDWLRQ 1LFNHOFRDWHG ZLUH LVPRUH GLIILFXOW WR VROGHU EXW PDNHV VDWLVIDFWRU FRQQHFWLRQV ZLWK SURSHU VROGHULQJ WHFKQLTXHV WARNING Avoid breathing the vapors from extruded polytetrafluoroethylene insulation when it is heated. Symptoms of overexposure are dizziness or headaches. These symptoms disappear upon exposure to fresh air. Q24. What safety precaution should you take when working with extruded polytetrafluoroethylene insulated wiring?Fluorinated Ethylene Propylene (FEP) )(3 KDV SURSHUWLHV VLPLODU WR H[WUXGHG SROWHWUDIOXRURHWKOHQH EXW ZLOO PHOW DW VROGHULQJWHPSHUDWXUHV ,W LV UDWHG DW ž DQG LV WKHUHIRUH FRQVLGHUHG D KLJKWHPSHUDWXUH LQVXODWLRQ 7KHUH DUH QRNQRZQ WR[LF YDSRUV IURP )(3 RPPRQVHQVH SUDFWLFH KRZHYHU UHTXLUHV WKDW RX SURYLGH DGHTXDWHYHQWLODWLRQ GXULQJ DQ VROGHULQJ RSHUDWLRQAsbestos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void inhalation of asbestos fibers. Asbestos fibers have been found to cause severe lung damage (asbestosis) and cancer of the gastrointestinal tract. Follow Navy safety precautions when working with all asbestos products. 2QH WSH RI DVEHVWRVFRYHUHG ZLUH LV VKRZQ LQ ILJXUH ,W FRQVLVWV RI VWUDQGHG FRSSHU FRQGXFWRUVFRYHUHG ZLWK IHOWHG DVEHVWRV 7KH ZLUH LV LQ WXUQ FRYHUHG ZLWK DVEHVWRV EUDLG 7KLV WSH RI ZLUH LV XVHG LQPRWLRQSLFWXUH SURMHFWRUV DUF ODPSV VSRWOLJKWV KHDWLQJ HOHPHQW OHDGV DQG VR IRUWK Figure 1-9.—Asbestos Insulation.
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igure 1-10.—Asbestos and varnished cambric insulation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tate the reasons that the Navy is getting away from the use of asbestos insulation. Q26. State what happens to the insulating characteristics of asbestos when it gets wet.Paper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
  91. 91. FDEOH 2YHU WKLV D OHDG VKHDWK LV DSSOLHG 7KLV WSH RI FDEOH LV XVHG RQ YROWDJHV IURP YROWV WR YROWV Figure 1-11.—Paper-insulated power cables. Q27. What are the most common insulators used for extremely high voltages?Silk and Cotton ,Q FHUWDLQ WSHV RI FLUFXLWV IRU H[DPSOH FRPPXQLFDWLRQV FLUFXLWV
  92. 92. D ODUJH QXPEHU RI FRQGXFWRUV DUHQHHGHG SHUKDSV DV PDQ DV VHYHUDO KXQGUHG )LJXUH VKRZV D FDEOH FRQWDLQLQJ PDQ FRQGXFWRUV(DFK LV LQVXODWHG IURP WKH RWKHUV E VLON DQG FRWWRQ WKUHDG %HFDXVH WKH LQVXODWLRQ LQ WKLV WSH RI FDEOH LVQRW VXEMHFWHG WR KLJK YROWDJH WKH XVH RI WKLQ ODHUV RI VLON DQG FRWWRQ LV VDWLVIDFWRU Figure 1-12.—Silk and cotton Insulation. 6LON DQG FRWWRQ LQVXODWLRQ NHHSV WKH VL]H RI WKH FDEOH VPDOO HQRXJK WR EH KDQGOHG HDVLO 7KH VLON DQGFRWWRQ WKUHDGV DUH ZUDSSHG DURXQG WKH LQGLYLGXDO FRQGXFWRUV LQ UHYHUVH GLUHFWLRQV 7KH FRYHULQJ LV WKHQLPSUHJQDWHG ZLWK D VSHFLDO ZD[ FRPSRXQGEnamel 7KH ZLUH XVHG RQ WKH FRLOV RI PHWHUV UHODV VPDOO WUDQVIRUPHUV PRWRU ZLQGLQJV DQG VR IRUWK LVFDOOHG PDJQHW ZLUH 7KLV ZLUH LV LQVXODWHG ZLWK DQ HQDPHO FRDWLQJ 7KH HQDPHO LV D VQWKHWLF FRPSRXQG RIFHOOXORVH DFHWDWH ZRRG SXOS DQG PDJQHVLXP
  93. 93. ,Q WKH PDQXIDFWXULQJ SURFHVV WKH EDUH ZLUH LV SDVVHGWKURXJK D VROXWLRQ RI KRW HQDPHO DQG WKHQ FRROHG 7KLV SURFHVV LV UHSHDWHG XQWLO WKH ZLUH DFTXLUHV IURP WR FRDWLQJV 7KLFNQHVV IRU WKLFNQHVV HQDPHO KDV KLJKHU GLHOHFWULF VWUHQJWK WKDQ UXEEHU ,W LV QRW
  94. 94. SUDFWLFDO IRU ODUJH ZLUHV EHFDXVH RI WKH H[SHQVH DQG EHFDXVH WKH LQVXODWLRQ LV UHDGLO IUDFWXUHG ZKHQ ODUJHZLUHV DUH EHQW )LJXUH VKRZV DQ HQDPHOFRDWHG ZLUH (QDPHO LV WKH WKLQQHVW LQVXODWLQJ FRDWLQJ WKDW FDQ EHDSSOLHG WR ZLUHV +HQFH HQDPHOLQVXODWHG PDJQHW ZLUH PDNHV VPDOOHU FRLOV (QDPHOHG ZLUH LV VRPHWLPHVFRYHUHG ZLWK RQH RU PRUH ODHUV RI FRWWRQ WR SURWHFW WKH HQDPHO IURP QLFNV FXWV RU DEUDVLRQV Figure 1-13.—Enamel Insulation. Q28. What is the common name for enamel-insulated wire?Mineral Insulated 0LQHUDOLQVXODWHG 0,
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  96. 96. Figure 1-14.—Two-conductor mineral-insulated (MI) cable. CONDUCTOR PROTECTION :LUHV DQG FDEOHV DUH JHQHUDOO VXEMHFW WR DEXVH 7KH WSH DQG DPRXQW RI DEXVH GHSHQGV RQ KRZ DQGZKHUH WKH DUH LQVWDOOHG DQG WKH PDQQHU LQ ZKLFK WKH DUH XVHG DEOHV EXULHG GLUHFWO LQ WKH JURXQG PXVWUHVLVW PRLVWXUH FKHPLFDO DFWLRQ DQG DEUDVLRQ :LUHV LQVWDOOHG LQ EXLOGLQJV PXVW EH SURWHFWHG DJDLQVWPHFKDQLFDO LQMXU DQG RYHUORDGLQJ :LUHV VWUXQJ RQ FURVVDUPV RQ SROHV PXVW EH NHSW IDU HQRXJK DSDUW VRWKDW WKH ZLUHV GR QRW WRXFK 6QRZ LFH DQG VWURQJ ZLQGV PDNH LW QHFHVVDU WR XVH FRQGXFWRUV KDYLQJ KLJKWHQVLOH VWUHQJWK DQG VXEVWDQWLDO IUDPH VWUXFWXUHV
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  133. 133. ANSWERS TO QUESTIONS Q1. THROUGH Q36. A1. To allow comparisons between conductors of different sizes and resistance. A2. 375 mils (move the decimal three places to the right). A3. A circular conductor with a diameter of 1 mil and a length of 1 foot. A4. The cross-sectional area of a square conductor with a side of 1 mil. A5. The cross-sectional area of a circular conductor with a diameter of 1 mil. A6. Circular mil area (CMA) = D2 (in mils) × number of strands0.0004 inch = 4 mils (CMA) = 4 2 × 19 (strands)(CMA) = 16 × 19 = 304 mils. A7. The resistance of a unit volume of a substance. A8. Length, cross-sectional area, and specific resistance of a unit volume of the substance from which the conductor is made. A9. 1,000 ft = 10.4 ohms1,500 ft = 1.5 × 0.4 = 15.6 ohmsA10. In the parallel walled slot not the circular area.A11. Conductor size, the material it is made of the location of the wire in a circuit, and the type of insulation used.A12. FEP, extruded polytetrafluoroethylene, and silicone rubber.A13. The heat surrounding the conductor is an important part of total conductor heating.A14. It is light and reduces corona.A15. It has higher conductivity, it is more ductile, it has relatively high tensile strength, and it can be easily soldered.A16. The amount of increase in the resistance of a 1-ohm sample of the conductor per degree of temperature rise above 0º CA17. It increases.A18. Conductors have a very low resistance and insulators have a resistance that is so great that, for all practical purposes, they are nonconductors.A19. Insulation resistance and dielectric strength.A20. The resistance to current leakage through the insulation.A21. The ability of the insulation material to withstand potential difference.A22. By raising the voltage on a test sample until it breaks down.A23. To prevent the rubber insulation from deteriorating due to chemical action.A24. Avoid breathing the vapors when the insulation is heated.A25. Breathing asbestos fibers can cause lung disease and/or cancerA26. It will become a conductor.A27. Varnished cambric and oil-impregnated paper.A28. Magnet wire.
  134. 134. A29. Metallic coat.A30. Three.A31. Fibrous Braid.A32. Rubber-filled cloth tape and a combination of cotton cloth and rubber.A33. Jute and Asphalt coverings.A34. Sheath and armorA35. Alloy lead, pure lead, and reinforced lead.A36. Wire braid, steel tape, and wire armor
  135. 135. CHAPTER 2 WIRING TECHNIQUES LEARNING OBJECTIVES Upon completing this chapter, you should be able to: 1. State the basic requirements for any splice and terminal connection, including the preferred wire- stripping method. 2. State the reason the ends of the wire are clamped down after a Western Union splice has been made. 3. Explain the major advantage of the crimped terminal over the soldered terminal. 4. Name the two types of insulation commonly used for noninsulated splices and terminal lugs. 5. State an advantage of using preinsulated terminal lugs and the color code used for each. 6. Explain the procedures for crimping terminal lugs with a hand crimp tool. 7. Recall the physical description and operating procedures for the HT-900B/920B compressed air/nitrogen heating tool. 8. Recall the safety precautions for using the compressed air/nitrogen heating tool. 9. Recall the procedures, precautions, and tools associated with soldering. 10. Explain the procedures and precautions for tinning wire. 11. Recall the types of soldering irons and their uses. 12. State the purposes and required properties of flux. 13. State the purpose for lacing conductors. 14. Recall when double lacing of wire bundles is required. 15. Recall the requirements for using spot ties. WIRING TECHNIQUES This chapter will assist you in learning the basic skills of proper wiring techniques. It explains thedifferent ways to terminate and splice electrical conductors. It also discusses various soldering techniquesthat will assist you in mastering the basic soldering skills. The chapter ends with a discussion of theprocedure to be followed when you lace wire bundles within electrical and electronic equipment. 2-1
  136. 136. CONDUCTOR SPLICES AND TERMINAL CONNECTIONS Conductor splices and connections are an essential part of any electrical circuit. When conductorsjoin each other or connect to a load, splices or terminals must be used. Therefore, it is important that theybe properly made. Any electrical circuit is only as good as its weakest link. The basic requirement of anysplice or connection is that it be both mechanically and electrically as sound as the conductor or devicewith which it is used. Quality workmanship and materials must be used to ensure lasting electricalcontact, physical strength, and insulation. The most common methods of making splices and connectionsin electrical cables is explained in the discussion that follows.INSULATION REMOVAL The preferred method of removing insulation is with a wire-stripping tool, if available. A sharp knifemay also be used. Other typical wire strippers in use in the Navy are illustrated in figure 2-1. The hot-blade, rotary, and bench wire strippers (views A, B, and C, respectively) are usually found in shops wherelarge wire bundles are made. When using any of these automatic wire strippers, follow the manufacturersinstructions for adjusting the machine; this avoids nicking, cutting, or otherwise damaging the conductors.The hand wire strippers are common hand tools found throughout the Navy. The hand wire strippers(view D of figure 2-1) are the ones you will most likely be using. Wire strippers vary in size according towire size and can be ordered for any size needed. Figure 2-1.—Typical wire-stripping tools. 2-2
  137. 137. Hand Wire Stripper The procedure for stripping wire with the hand wire stripper is as follows (refer to figure 2-2): Figure 2-2.—Stripping wire with a hand stripper. 1. Insert the wire into the center of the correct cutting slot for the wire size to be stripped. The wire sizes are listed on the cutting jaws of the hand wire strippers beneath each slot. 2. After inserting the wire into the proper slot, close the handles together as far as they will go. 3. Slowly release the pressure on the handles so as not to allow the cutting blades to make contact with the stripped conductor. On some of the newer style hand wire strippers, the cutting jaws have a safety lock that helps prevent this from happening. Continue to release pressure until the gripper jaws release the stripped wire, then remove.Knife Stripping A sharp knife may be used to strip the insulation from a conductor. The procedure is much the sameas for sharpening a pencil. The knife should be held at approximately a 60º angle to the conductor. Useextreme care when cutting through the insulation to avoid nicking or cutting the conductor. Thisprocedure produces a taper on the cut insulation as shown in figure 2-3. 2-3
  138. 138. Figure 2-3.—Knife stripping.Locally Made Hot-Blade Wire Stripper If you are required to strip a large number of wires, you can use a locally made hot-blade stripper(figure 2-4) as follows: Figure 2-4.—Locally made hot-blade stripper. 1. In the end of a piece of copper strip, cut a sharp-edged V. At the bottom of the V, make a wire slot of suitable diameter for the size wire to be stripped. 2. Fasten the copper strip around the heating element of an electric soldering iron as shown in figure 2-4. The iron must be rated at 100 watts or greater in order to transfer enough heat to the copper strip to melt the wire insulation. 3. Lay the wire or cable to be stripped in the V; a clean channel will be melted in the insulation. 2-4

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