Kev piav qhia yooj yim: Hauv cov qauv cable, cov xaim hauv av tau muab tso rau ntawm cov khub thiab tag nrho cov twist tiav, tag nrho cov uas yog hu ua ob lub hauv av xaim. Los ntawm qhov pom ntawm cov phau ntawv lub cev, lub luag haujlwm tseem ceeb ntawm cov xaim hauv av yog kom tsis txhob xob laim thiab qhia tam sim no rau hauv nws. Rau hauv av, thaum cov khoom siv hluav taws xob xau los yog qhov hluav taws xob siab dhau lawm, tam sim no tau nkag mus rau hauv av los ntawm cov xaim hauv av. Cov xov hlau shielded peb tsim, muab ib qho thiab hauv av xaim ntawm braided thiab tag nrho cov twisted aluminium ntawv ci thaum lub sij hawm tag nrho twisting, nws lub luag haujlwm tseem ceeb yog tiv thaiv cov teeb liab sab nraud, tsis yog lub teeb liab ntawm lub cable nws tus kheej, hauv av hlau hauv txhua khub, Lub hom phiaj tseem ceeb yog los tiv thaiv kev cuam tshuam ntawm cov cables hauv cov qauv cable.
Lub luag haujlwm ntawm kev tiv thaiv yog cais cov suab nrov ntawm electromagnetic teb los ntawm cov khoom siv rhiab thiab txiav tawm txoj kev nthuav tawm ntawm lub suab nrov. Shielding yog muab faib ua active shielding thiab passive shielding. Lub hom phiaj ntawm active shielding yog los tiv thaiv lub suab nrov los ntawm radiating sab nraud, uas yog lub shielding ntawm lub suab nrov; lub hom phiaj ntawm passive shielding yog los tiv thaiv cov khoom rhiab heev los ntawm kev cuam tshuam los ntawm lub suab nrov, uas yog kev tiv thaiv ntawm cov khoom rhiab heev. Lub shielding txheej ntawm shielded cable yog tsuas yog ua los ntawm cov ntaub ntawv uas tsis yog-magnetic xws li tooj liab thiab txhuas, thiab cov thickness yog heev nyias, uas yog ntau me dua li ntawm daim tawv nqaij qhov tob ntawm cov khoom siv hlau ntawm qhov zaus ntawm kev siv. Cov nyhuv ntawm cov txheej thaiv tsis yog tsuas yog vim qhov kev xav ntawm lub tshuab hluav taws xob thiab cov hlau nplaum los ntawm lub cev hlau nws tus kheej. , absorption, tab sis vim yog grounding ntawm shielding txheej. Cov ntawv sib txawv hauv av yuav cuam tshuam ncaj qha rau cov nyhuv thaiv. Rau txoj kev sib txawv hauv av ntawm cov hluav taws xob thiab cov hlau nplaum tiv thaiv cov khaubncaws sab nraud povtseg, ungrounded, ib leeg-kawg lossis ob-kawg grounding yuav siv tau.
Ib leeg-kawg grounding: Cov xaim hauv av hauv txhua khub feem ntau yog los tiv thaiv kev cuam tshuam ntawm cov cables hauv cov qauv cable. Ib qho kawg grounding ntawm shielded cables yuav pab tau kom tsis txhob muaj kev cuam tshuam ntawm tsawg zaus hluav taws xob teb. Grounding cov ntaub thaiv npog cable ntawm ib kawg tiv thaiv tsis tshua muaj suab nrov tam sim no ntawm daim ntaub thaiv. Qhov tam sim no sab hauv ua rau muaj kev cuam tshuam ntau hom hluav taws xob thiab tuaj yeem cuam tshuam nrog cov khoom siv analog. Ib leeg-kawg grounding ntawm daim ntaub thaiv npog yog pom zoo rau circuits uas rhiab heev rau tsawg-zaus cuam tshuam (analog circuits). Kev hloov pauv thiab qhov sib txawv mus tas li hauv kev ntsuas ua tiav qhia tau tias muaj kev cuam tshuam tsawg zaus. Ib qho kawg grounding ntawm shielding txheej yog ncaj qha rau hauv av cov hlau thaiv txheej ntawm ib kawg ntawm shielded cable, thiab lwm yam kawg yog tsis grounded. Nyob rau hauv cov ntaub ntawv ntawm ib leeg-kawg grounding ntawm shielding txheej, muaj ib tug induced voltage ntawm cov hlau shielding txheej ntawm tsis-grounding kawg thiab hauv av, thiab induced voltage yog proportional rau qhov ntev ntawm cable, tab sis lub shielding txheej. tsis muaj peev xwm circulating tam sim no. Ib leeg-kawg grounding yog siv qhov kev tawm tsam muaj peev xwm sib txawv kom ua tiav lub hom phiaj ntawm kev tshem tawm electromagnetic cuam tshuam. Txoj kev hauv av no tsim nyog rau cov kab luv luv, thiab qhov cuam tshuam ntawm qhov hluav taws xob sib txuas nrog lub cable ntev tsis tuaj yeem tshaj qhov kev nyab xeeb voltage. Qhov muaj nyob ntawm electrostatic induced voltage yuav cuam tshuam rau kev ruaj ntseg ntawm lub teeb liab Circuit Court, thiab tej zaum yuav tsim ib tug kav hlau txais xov nyhuv.
Ob chav-kawg grounding: Feem ntau, kev xaim impedance ntawm cov hlau ntawv hlau thaiv txheej yog ntau dua li ntawm cov tooj liab braided hlau, thiab nws cov nyhuv yog 5-10 zaus sib txawv, yog li nws tsis tuaj yeem siv los ua cov teeb liab digital. Yog hais tias lub shielding txheej ntawm cable heats li thaum lub shielding txheej yog grounded ntawm ob hnub, los yog yog hais tias lub shielding txheej catches hluav taws thaum nws kov lub vaj tse ntawm hluav taws xob tswj txee los yog lub shielded tsheb npav, nws txhais tau hais tias lub equipotential bonding yog unreliable. Ob-kawg grounding yog txuas rau ob qhov kawg ntawm cov hlau thaiv ntawm lub shielded cable rau hauv av. Nyob rau hauv rooj plaub uas lub shielding txheej yog grounded ntawm ob kawg, cov hlau shielding txheej yuav tsis tsim induced voltage, tab sis cov hlau shielding txheej yuav raug cuam tshuam los ntawm kev cuam tshuam magnetic flux, thiab ib tug shielding circulating tam sim no yuav dhau mus. Yog tias qhov muaj peev xwm ntawm qhov chaw A thiab qhov chaw B tsis sib npaug, lub peev xwm loj yuav raug tsim Circulation, uas yuav muaj qhov cuam tshuam rau qhov cuam tshuam ntawm lub teeb liab. Ob sab ntawm lub hwj chim cable yog grounded, thiab PE ntawm lub cev muaj zog kawg yuav tsum tau txuas nrog PE ntawm tus tsav kawg, thiab thaum kawg txuas nrog lub ntiaj teb tsheb npav hauv lub chassis. Cov kab teeb liab yuav tsum tau kho txawv. Feem ntau hais lus, analog teeb liab tawm tswv yim ib leeg-kawg grounding kom tsis txhob muaj av tam sim no los ntawm qhov sib txawv hauv av los ntawm kev cuam tshuam cov teeb liab thaum ob-kawg grounding; cov teeb liab lossis cov teeb liab sib txawv tawm tswv yim ob-kawg grounding, tab sis hauv av loj heev. Tam sim no kuj tuaj yeem cuam tshuam rau lub teeb liab.
Nws puas tuaj yeem ua tsis tau?
Thaum tus qauv qauv tsim, cov xaim hauv av feem ntau muaj nyob rau hauv cov qauv tiv thaiv kab mob, thiab muaj tsawg kawg yog ib qho tooj liab hlau nyob rau hauv ib daim ntaub thaiv npog thiab ob daim ntaub thaiv npog, uas yog, hauv av xaim. Nws tseem yog cov av xaim xaim txuas nrog cov txheej thaiv ntawm aluminium ntawv ci, thiab cov xaim hauv av tuaj yeem tiv thaiv cov teeb meem sab nraud zoo dua. Lub shielded hlau yuav tsum tau zoo grounded, thiab shielded hlau yuav txo tau cov kev cuam tshuam ntawm muaj zog cuam tshuam rau lub network teeb liab. Txawm li cas los xij, nyob rau hauv lub sijhawm muaj kev cuam tshuam loj heev, thaum tus nqi txiav txim siab txog kev ua lag luam, ntau lub tuam txhab tshem tawm cov xaim hauv av hauv cov qauv sib txawv kom tsis txhob ua tiav cov txiaj ntsig ntawm kev txo cov nqi, tab sis yog tias cov neeg siv khoom thov scenario tshwj xeeb, yog qhov hu ua yooj yim. version yog siv, nws yuav coj cov teeb liab loj heev attenuation rau daim ntawv thov davhlau ya nyob twg.
