Electrotechnical cov ntaub ntawv, cov khoom thiab cov kev siv

Efficiency thiab durability ntawm hluav taws xob cov cav tov thiab nroj tsuag nyob rau hauv lub zwj ceeb ntawm cov rwb thaiv tsev, hluav taws xob pab kiag li lawm uas cov ntaub ntawv siv. Lawv tsiag ntawv los ntawm ib tug txheej ntawm tej zog thaum muab tso rau hauv ib qho electromagnetic teb tej yam kev mob, thiab yog ntsia tau rau hauv pab kiag li lawm raws li tej cim no.

Classification hluav taws xob ntaub ntawv pub muab faib mus rau hauv tej pawg neeg nyias ntawm insulating, semiconducting, kev thiab sib nqus ntaub ntawv uas ntxiv zog rau cov khoom tseem ceeb: capacitors, conductors, isolators thiab semiconductor ntsiab npaj.

Ntaub ntawv ua raws li ib tug neeg sib nqus los yog hluav taws xob teb nrog tej khoom, thiab yog raug rau ntau yam radiations ib txhij. Sib Nqus ntaub ntawv conventionally muab faib mus rau hauv weakly magnetic tshuaj thiab sib nqus tshuaj. Nyob rau hauv qhov hluav taws xob txheej txheem feem ntau ua hauj lwm muaj zog sib nqus cov ntaub ntawv.

ntaub ntawv science

Cov khoom yog hais tias yam khoom uas, yus muaj los ntawm cov los ntawm lwm yam khoom ntawm lub tshuaj nyob tus yeees, zog thiab cov qauv ntawm molecules thiab atoms. Cov tshuaj yeeb dej caw yog nyob rau hauv ib qho ntawm plaub lub xeev: gaseous, khoom, kua los yog ntshav. Hluav taws xob thiab cov yam ntxwv ntaub ntawv ua rau nruab ntau yam ntawm kev khiav dej num.

Ua ntaub ntawv kis electrons txaus Cheebtsam muab dielectric rho tawm. Daim ntawv thov ntawm lub resistor ntsiab converting hluav taws xob lub zog mus rau hauv tshav kub, cov ntaub ntawv ntawm kev tsim kho cov khoom khaws lawv zoo lawm, e.g., lub vaj tse. Hluav taws xob thiab siv cov ntaub ntawv yuav tsum tau ua tsis muaj ib tug tab sis ob peb txog kev khiav dej num, xws li ib tug insulator nyob rau hauv qhov hluav taws xob load kev ntsuam xyuas, uas coj nws mus yam ntxwv cov ntaub ntawv.

Hluav taws xob cov ntaub ntawv science - lub science soj ntsuam nrog lub ntsiab txhais ntawm lub thaj chaw, txoj kev tshawb ntawm tus cwj pwm ntawm qhov teeb meem nyob rau hauv tus ntawm hluav taws xob, Thaum tshav kub kub, txias, magnetic teb thiab lwm yam science tshawb fawb cov kev yam ntxwv yuav tsum tau los tsim kom tau hluav taws xob cav, pab kiag li lawm thiab sib ..

ntawm cov

Cov no muaj xws hluav taws xob khoom, uas yog lub ntsiab qhia qhia conductivity ntawm hluav taws xob tam sim no. Qhov no yog vim hais tias nyob rau hauv lub loj ntawm ib yam khoom uas ib txwm tam sim no electrons yog weakly ua txhua yam rau lub nucleus thiab ua dawb xwb muaj. Lawv tsiv mus nyob nrog lub orbit ntawm ib tug qauv rau lwm tus thiab ua tau ib lub tam sim no. Lub ntsiab conductive ntaub ntawv xam tau tias yog tooj liab, txhuas.

Mus rau conductors yog hais tias muaj ib tug hluav taws xob resistivity ρ <10 ^-5, nyob rau hauv cov ntaub ntawv yog ib qho zoo heev neeg xyuas pib nrog ib tug qhia 10 ^-8 Ohm * m. Tag nrho cov co muaj ib tug zoo tam sim no lub rooj ntawm 105 ntsiab 25 yog tsis tau tsuas yog co, thiab los ntawm no ntau haiv neeg cov ntaub ntawv 12 coj hluav taws xob tam sim no thiab pom tau hais tias raws li semiconductors.

Lub physics ntawm hluav taws xob ntaub ntawv tso cai rau lawv siv raws li cov neeg ua hauj nyob rau hauv lub gaseous thiab kua xeev. Raws li cov kua hlau ntawm txwm kub yog thov tsuas mercury, rau cov uas lub ntuj lub xeev. Tus lwm yam co siv raws li conductors tsuas ua kua nyob rau hauv ib tug rhuab lub xeev. Rau conductors siv thiab conductive kua, piv txwv li ntsha. Tseem ceeb thaj chaw ntawm lub conductors, uas paub qhov txawv lawv raws li cov neeg kawm ntawv ntawm hluav taws xob conductivity, thermal conductivity yam ntxwv pom tau hais tias thiab muaj peev xwm mus thermal tiam.

dielectric ntaub ntawv

Tsis zoo li conductors, dielectrics loj muaj ib tug me me muaj pes tsawg tus ntawm dawb electrons elongated lub cev. Lub ntsiab cuab yeej ntawm tus tshuaj yog nws muaj peev xwm tau txais cov polarity ntawm lub electric teb. Qhov no tshwm sim yog piav los ntawm qhov tseeb hais tias nyob rau hauv tus ntawm hluav taws xob-hais txog nqi yeej nyob rau hauv cov kev taw qhia ntawm sawv rog. Lub offset deb yog ntau dua, ntau dua qhov lub electric teb lub dag lub zog.

Hluav taws xob cov insulating cov ntaub ntawv yog cov los ze zog mus rau lub zoo tagnrho tshaj tus me index conductivity, thiab tsawg pronounced tshaj cov neeg kawm ntawv ntawm polarization, uas muab ib tug hais txog ntawm dispersion thiab thermal zog qee. Lub conductivity ntawm lub dielectric yog raws li nyob rau hauv qhov kev txiav txim ntawm ib tug me me npaum li cas ntawm free dipoles hloov rau qhov kev txiav txim ntawm lub teb. Tom qab polarization, lub dielectric tshuaj ntaub ntawv uas txawv polarity, i.e., ob nqi sib txawv ntawm cov cim tsim nyob rau saum npoo av.

Daim ntawv thov dielectrics feem ntau feem nyob rau hauv hluav taws xob, txij li thaum siv cov active thiab passive caij yam ntxwv.

Rau cov active khoom, muaj zog amenable mus tswj, muaj xws li:

• pyroelectrics;
• electroluminophors;
• piezoelectrics;
• ferroelectrics;
• electrets;
• cov ntaub ntawv rau emitters nyob rau hauv lub laser.

Basic hluav taws xob cov ntaub ntawv - dielectric passive zog, yog siv raws li insulating cov ntaub ntawv thiab capacitors ntawm cov pa hom. Lawv yog cov tau cais ob tug hlob ntawm hluav taws xob Circuit Court los ntawm txhua lwm yam thiab tiv thaiv kom txhob nchuav ntawm hluav taws xob nqi. Txij li thaum lawv rho tawm yog nqa tawm ntawm qhov tam sim no-nqa qhov chaw rau hluav taws xob lub zog yog nyob rau hauv lub hauv av los yog nyob rau hauv lub vaj tse nyob.

sib cais los ntawm ib tug insulator

Nyob rau hauv cov organic thiab inorganic dielectric ntaub ntawv raug muab faib, nyob ntawm seb cov tshuaj muaj pes tsawg leeg. Inorganic dielectrics tsis muaj carbon nyob rau hauv nws muaj pes tsawg leeg, thaum lub sij hawm organic ntaub ntawv yog thawj carbon caij. Inorganic tshuaj xws li ceramics, mica, ib tug high degree ntawm tshav kub.

Hluav taws xob cov khoom nyob rau hauv ib txoj kev ua muab faib mus rau hauv tej yam ntuj tso thiab dag dielectrics. Lub dav siv ntawm cov khoom cua ntaub ntawv yog raws li nyob rau hauv lub fact tias siv tso cai rau kom muab cov ntaub ntawv uas cov yam khoom.

Raws li cov qauv ntawm cov molecules thiab molecular lattice dielectrics muab faib mus rau hauv ncov qaumteb qabteb thiab uas tsis yog-polar. Qhov kawg no kuj hu ua nruab nrab. Qhov txawv yog hais tias lub atoms thiab molecules ua ntej lawv txiav txim rau lub fais tam sim no los sis tsis muaj hluav taws xob xwb. K yog ib tug nruab nrab pab pawg neeg no muaj xws li Teflon, polyethylene, mica, quartz, thiab lwm tus neeg. Lub ncov qaumteb qabteb dielectrics muaj molecules nrog ib tug zoo los yog tsis zoo xwb, ib qho piv txwv yog polyvinyl tshuaj dawb, bakelite.

dielectric zog

Raws li dielectrics muab faib mus rau hauv gaseous, kua thiab khoom. Cov feem ntau siv khoom hluav taws xob cov ntaub ntawv. Lawv lub zog thiab daim ntawv thov soj ntsuam siv tsis thiab yam ntxwv:

• ib tug ntim resistivity;
• dielectric permittivity;
• ib tug saum npoo resistivity;
• lub coefficient ntawm thermal permeability;
• dielectric tsis tangent ntawm lub kaum sab xis qhia;
• lub dag lub zog ntawm cov khoom nyob rau hauv tus ntawm hluav taws xob.

Volume resistivity nyob rau hauv lub peev xwm ntawm ib tug cov ntaub ntawv uas rau thaum nws to thereon qhov nqi tam sim no. Qhov taw qhia rov qab resistivity hu ua tej conductivity.

Deg resistivity yog txiav txim los ntawm lub peev xwm ntawm cov khoom siv tawv rau qhov tam sim no ntws rau nws saum npoo. Deg conductivity yog lub reciprocal ntawm yav tas los daim duab.

Lub coefficient ntawm thermal permeability qhia cov neeg kawm ntawv uas hloov nyob rau hauv resistivity tom qab raising tus kub ntawm cov tshuaj yeeb dej caw. Feem ntau, cov kuj txo nrog ua kub, yog li ntawd, cov coefficient nqi yog tsis zoo.

Lub dielectric qhov txiav txim qhov hluav taws xob daim ntawv thov cov ntaub ntawv nyob rau hauv raws li lub peev xwm ntawm cov khoom los tsim hluav taws xob capacitance. Measure ntawm tus kwv tij permittivity ntawm lub dielectric muaj nyob rau hauv lub tswvyim ntawm meej permeability. Hloov rwb thaiv tsev muaj peev xwm taw qhia tso tawm kom pom yav dhau los thermal permeability coefficient, uas ib txhij qhia ib qho kev nce los yog txo nyob rau hauv capacitance nrog ib tug kev hloov nyob rau hauv kub.

Tangent ntawm dielectric tsis lub kaum sab xis qhia cov neeg kawm ntawv cov saw hwj chim tsis muaj respect rau cov dielectric khoom raug rau ib tug hluav taws xob alternating tam sim no.

Tsiag ntawv Electrotechnical ntaub ntawv ntawm dielectric zog qhia, uas txiav txim tau ntawm kev rhuav tseg cov tshuaj yeeb dej caw nyob rau hauv kev nyuaj siab. Nyob rau hauv paub tus neeg kho tshuab zog ntawm ib tug xov tooj ntawm cov kev ntsuam xyuas kom txhim tsa lub Performance index txwv compressive zog, tensile, dabtsi yog khoov, torsional, tej yam thiab puas.

Lub cev thiab tshuaj cov yam ntxwv ntawm dielectrics

Nyob rau hauv dielectrics muaj ib tug tej yam muaj pes tsawg tus ntawm tso acids. Tus nqi ntawm cov poov tshuaj nyob rau hauv hydroxide milligrams yuav tsum tau kom tshem tau ntawm impurities nyob rau hauv 1 g ntawm yam khoom uas yog hu ua acid tooj. Acids puas cov ntaub ntawv organic muaj ib tug tsis ntxim rau cov insulating zog.

Yam ntxwv hluav taws xob ntaub ntawv complemented viscosity coefficient los yog kev sib txhuam, uas qhia cov neeg kawm ntawv uas txaus ntawm qhov teeb meem. Viscosity yog muab faib ua zwj ceeb thiab kinematic.

Degree dej haum yog txiav txim nyob rau hauv lub loj ntawm dej absorbed los ntawm lub xeem caij loj hnub tom qab immersion rau hauv dej rau ib predetermined kub. Qhov no characterization qhia cov porosity ntawm cov khoom, nce lub Performance index deteriorates lub insulating zog.

magnetic ntaub ntawv

Performance kev luj xyuas ntawm tus sib nqus no hu ua cov magnetic yam ntxwv:

• Sib Nqus tsis permeability;
• magnetic txheeb ze permeability;
• thermal coefficient ntawm magnetic permeability;
• zog tshaj plaws magnetic teb.

Sib Nqus ntaub ntawv raug muab faib ua nyuaj thiab mos mos. Cov mos mos ntsiab yog yus muaj los ntawm me me losses lagging magnitude ntawm magnetization ntawm lub cev kuj magnetic teb. Lawv yog cov ntau permeable mus rau lub sib nqus tsis muaj ib tug me me coercive quab yuam thiab ib tug ntau dua kev tsuas xyaus induction. Lawv siv nyob rau hauv lub ntaus ntawv transformers ntawm electromagnetic cov cav tov thiab mechanisms, magnetic shields los yog lwm yam khoom uas nws yog tsim nyog magnetization nrog tsis muaj zog omissions. Cov no muaj xws ntshiab electrolytic hlau, hlau - Armco, permalloy, hluav taws xob steel los xij, npib tsib xee-hlau alloys.

Khoom ntaub ntawv no yog yus muaj los ntawm ib tug tseem ceeb tsis lagging degree ntawm magnetization rau lwm magnetic teb. Tau txais ib zaug magnetic pulses, xws hluav taws xob cov ntaub ntawv thiab cov khoom uas magnetized, thiab rau ib ntev lub sij hawm mus kom cov muab lub zog. Lawv muaj ib tug siab coercive quab yuam thiab siab residual induction muaj peev xwm. Hais nrog cov yam ntxwv yog siv rau qhov siv thiab nyob ruaj ruaj hlau nplaum. Cov neeg sawv cev ntawm cov ntsiab yog alloys raws li hlau, txhuas, npib tsib xee, cobalt, pob zeb ntais Cheebtsam.

magnetodielectrics

Qhov no tov khoom, 75-80% nyob rau hauv muaj pes tsawg leeg uas muaj lub magnetic hmoov, qhov loj ntawm cov organic siab polymeric residue yog lawm ua tus sau nrog dielectric. Y ferrites thiab ferrites nce qhov tseem ceeb ntawm volume resistivity, me me eddy tam sim no losses, uas tso cai rau lawv siv nyob rau hauv high-zaus technology. Ferrites yog ruaj khov ntsuas nyob rau hauv txawv zaus teb.

Teb siv ferromagnets

Lawv yog siv feem ntau zoo los ua ib tug tub ntxhais ntawm transformer coils. Daim ntawv thov ntawm cov ntaub ntawv uas tso cai rau kom kom ntau npaum li cas lub sib nqus teb ntawm lub transformer, thaum tsis hloov tam sim no kev nyeem ntawv ntawm kev quab yuam. Tej zoo ntawm cov ferrite yam zog noj thaum lub sij hawm kev lag luam ntawm tus dais. Hluav taws xob cov ntaub ntawv thiab cov khoom siv tom qab lwm magnetic cawv khaws magnetic yam ntxwv, thiab koom tes rau ib daim teb nyob rau hauv lub nyob ib sab qhov chaw.

Elementary currents tsis muaj tias tom qab switching tawm cov hlau nplaum, yog li tsim ib tug qauv ruaj khov magnet uas ua hauj lwm zoo nyob rau hauv headphones, xov tooj, xab pab kiag li lawm, compasses, suab cov ntaubntawv povthawj siv kiag li lawm. Heev nrov nyob rau hauv lub siv ntawm mus tas li cov hlau nplaum, tsis electrically conductive. Tau compound ntawm hlau oxides nrog rau ntau yam lwm yam oxides. Lodestone hais txog ferrite.

semiconductor ntaub ntawv

Cov no yog cov ntsiab uas muaj ib tug conductivity nqi uas yog nyob rau hauv lub luv ntawm no Performance index rau conductors thiab dielectrics. Lub conductivity ntawm cov ntaub ntawv nyob rau hauv lub hav zoov ntawm impurities nyob rau hauv hnyav, lwm yam thiab cov lus qhia ntawm sab hauv tsis xws luag.

Cov yam ntxwv ntawm electrotechnical ntaub ntawv semiconductors pab pawg neeg qhia tau hais tias tseem ceeb sib txawv los ntawm txhua lwm yam hais rau cov lattice qauv, muaj pes tsawg leeg thiab zog. Nyob ntawm seb cov tsis, cov ntaub ntawv yog txwv kom muab zais rau hauv 4 hom:

1. Hais atoms muaj ib zaug xwb hom: pob zeb ntais, phosphorus, boron, selenium, indium, germanium, gallium, thiab lwm tus neeg.
2. Ntaub ntawv uas muaj hlau oxides muaj li ntawm - tooj liab oxide, cadmium, zinc thiab lwm tus neeg.
3. Cov ntaub ntawv nyob rau hauv lub neej coj pab pawg neeg antimonide.
4. Organic cov ntaub ntawv - naphthalene, anthracene, thiab lwm tus neeg.

Nyob rau hauv lub ntxaij ntoo muab faib ua polycrystalline semiconductor cov ntaub ntawv thiab monocrystalline ntsiab. Cov yam ntxwv ntawm hluav taws xob ntaub ntawv tso cai rau lawv mus qhia nyob rau hauv qhov uas tsis yog-sib nqus thiab weakly. Ntawm cov Cheebtsam ntawm magnetic paub qhov txawv semiconductors, conductors thiab uas tsis yog-conductive ntsiab. Clear faib yog ib qhov nyuaj rau ua, vim muaj ntau yam ntaub ntawv coj txawv nyob rau hauv ib tug hloov ib puag ncig. Piv txwv li, lub lag luam ntawm ib co semiconductors thaum uas tsis muaj kub muaj peev xwm yuav muab piv nrog rau cov nyhuv uas cov insulators. Cov dielectrics los ntawm cua sov ua hauj lwm raws li semiconductors.

composite ntaub ntawv

Ntaub ntawv uas tsis muab faib rau cov hauj lwm thiab muaj pes tsawg leeg, hu ua puas cov ntaub ntawv, nws tseem yog hluav taws xob cov ntaub ntawv. Lawv lub zog thiab daim ntaub ntawv vim muaj ib tug ua ke ntawm cov ntaub ntawv siv nyob rau hauv qhov siv thiab ua. Piv txwv yog lub khob fiber ntawv Cheebtsam, fiberglass, mixtures ntawm conductive thiab refractory hlau. Siv mixtures sib npaug txawj qhia cov ntaub ntawv thiab thov lawv los rau lawv lo lus uas peb. Tej zaum ib tug ua ke ntawm puas yam ua rau yus lub creation ntawm ib tug nkaus tshiab caij mus rau lwm yam khoom.

zaj duab xis cov ntaub ntawv

Greater tau rau hluav taws xob foils thiab nplaum tapes muaj tau raws li hluav taws xob cov ntaub ntawv. Lawv lub zog yog txawv los ntawm lwm yam dielectrics yooj, txaus txhua yam muaj zog thiab zoo heev insulating zog. Lub thickness ntawm cov khoom nws txawv nyob ntawm seb cov ntaub ntawv uas:

• zaj duab xis thickness ntawm 6-255 microns ua, tso tawm daim kab xev 0,2-3,1 hli;
• polystyrene khoom nyob rau hauv daim ntawv ntawm cov tapes thiab films ua 20-110 microns tuab;
• tuab polyethylene daim kab xev ua 35-200 m, ib tug dav ntawm 250 mus rau 1500 hli;
• fluoroplastic zaj duab xis thickness yog ua 5 rau 40 microns, ib tug dav ntawm 10-210 hli envisage.

Ib suam ntawm hluav taws xob ntaub ntawv los ntawm cov zaj duab xis tso cai rau kom paub qhov txawv ob hom: oriented thiab uas tsis yog-taw qhia kom paub zaj duab xis. Tus thawj cov ntaub ntawv uas yog siv feem ntau.

Xim tsev thiab coatings rau hluav taws xob rwb thaiv tsev

Solutions ntawm tshuaj txoj kev thaum lub sij hawm solidification zaj duab xis yog niaj hnub hluav taws xob khoom. Qhov no pab pawg neeg no muaj xws li asphalts, kom qhuav roj, resins, cellulose esters los yog tebchaw thiab ob peb ua ke ntawm cov Cheebtsam. Conversion ntawm ib tug khov tivthaiv nyob rau hauv insulator tshwm sim tom qab evaporation ntawm cov kuab loj tso thiab txoj kev ua ib tug tuab zaj duab xis. Los ntawm txoj kev uas tso npe thov cov zaj duab xis yog muab faib ua nplaum, txheej thiab impregnation.

Impregnating varnishes siv rau hluav taws xob windings nyob rau hauv thiaj li yuav ua rau kom cov thermal conductivity thiab kuj mus ya raws. Txheej cov kua roj vanish sab sauv tsim ib tug tiv thaiv txheej tiv thaiv dej, txias, roj, nto winding, yas rwb thaiv tsev. Adhesive Cheebtsam muaj peev xwm lo mica phaj nrog rau lwm cov ntaub ntawv.

Tebchaw rau hluav taws xob rwb thaiv tsev

Cov ntaub ntawv tau hais ib cov kua tshuaj thaum lub sij hawm ntawm qhov kev siv, raws li los ntawm hardening thiab curing. Tshuaj yus muaj los ntawm qhov tseeb hais tias muaj pes tsawg leeg tsis muaj cov kuab tshuaj. Lub tebchaw kuj zwm rau cov pab pawg neeg "hluav taws xob khoom". Cov ntaub ntawv yog lawv casting thiab Impregnating roj nplua. Tus thawj hom yog siv rau sau muaj kab noj hniav nyob rau hauv cable couplings, thiab lub thib ob pab pawg neeg no yog siv rau impregnation ntawm lub cev muaj zog windings.

Tebchaw ua ib tug thermoplastic, lawv muag tom qab qhov kev nce nyob rau hauv kub, thiab thermosetting, steadfastly khaws cia rau hauv daim ntawv ntawm solidification.

Impregnated fibrous insulating cov ntaub ntawv

Zus tau tej cov xws ntaub ntawv siv organic fibers thiab tus txiv neej-ua Cheebtsam. Ntuj zaub fibers ntawm txhob lo lo ntxhuav, linen, ntoo remaking nyob rau hauv cov ntaub ntawv ntawm cov organic keeb kwm (fiber, ntaub, cov duab los qhia). Humidity ntawm xws insulators yog hom twg los ntawm 6-10%.

Organic ntaub ntawv ntawm cov khoom cua (nylon) muaj dej xwb 3 mus rau 5%, xws li kev tsuas xyaus ntawm dej thiab inorganic fibers (fiberglass). Inorganic ntaub ntawv yog yus muaj los ntawm ib tug tsis muaj peev xwm mus tua hluav taws thaum loj cua kub. Yog hais tias cov ntaub ntawv rau koj tsau enamels los yog lacquers, lub flammability qab. Mov ntawm hluav taws xob ntaub ntawv no yog ua nyob rau hauv lub chaw ua khoom ntawm hluav taws xob machinery thiab cov khoom siv.

Leteroid

Ib tug nyias fiber yog ua nyob rau hauv cov ntawv txheeb thiab kuav los tiag mus rau hauv ib yob rau kev thauj mus los. Nws siv raws li ib tug cov ntaub ntawv uas rau manufacturing cov rwb thaiv tsev gaskets, zoo li tus dielectrics txuas. Ntawv impregnated nrog asbestos thiab asbestos board ua los ntawm chrysotile asbestos, splitting nws mus rau hauv fibers. Asbestos muaj kuj mus alkaline tej yam kev mob, tab sis lov cia nyob rau hauv ib tug acid.

Nyob rau hauv xaus, nws yuav tsum tau muab sau tseg tias cov kev siv uas niaj hnub ntaub ntawv rau lub rwb thaiv tsev ntawm hluav taws xob khoom pab cuam lub neej yog ho muaj zog. Rau sib vaj tse siv ntaub ntawv nrog xaiv thaj chaw uas tso cai rau zus tau tej cov tshiab haumxeeb khoom nrog paub kev ua tau zoo.