Dab tsi yog selectivity? Muab xam los ntawm qhov kev xaiv ntawm cov khoom siv fais fab

Los ntawm selectivity peb txhais tau tias txoj haujlwm ua haujlwm zoo rau kev khiav haujlwm ntawm hluav taws xob kev tiv thaiv hluav taws xob. Raws li ib tug tshwm sim ntawm fuses los yog Circuit Court tej fais fab yog tiv thaiv thiab combustion thaiv tsis ua hauj lwm loads kev cob cog rua rau nws los ntawm luv luv circuits thiab exceedances denominations ntawm xaiv qhov chaw, thaum tus so ntawm lub Circuit Court tseem ua hauj lwm.

Tswvyim ntawm kev lag luam ntawm automata

Lub tswv yim ntawm kev xaiv li cas, koj tuaj yeem tau txais, yog tias koj xav txog lub tswv yim ntawm kev ua haujlwm ntawm lub tsev tso hluav taws xob.

Yog hais tias luv luv hauv lub qhov cub lossis hauv chav lwm qhov, tsuas yog cov khoom siv tiv thaiv uas yog nyob rau hauv qhov Circuit Court no yuav tsum ua haujlwm. Lub tshuab tsis siv neeg lub cav yuav tsis muab tua thiab yuav siv hluav taws xob mus rau seem ntawm cov seem. Yog tias qee yam laj thawj ntawm chav ua noj tsis ua haujlwm, ces tus kuaj xyuas seb qhov hluavtaws tawm ntawm lub qhov hluav taws xob los ntawm kev xa tawm lub hwj chim hauv txhua qhov hluav taws xob circuits.

Kev faib tawm

Dab tsi yog qhov selectivity ntawm automata tuaj yeem sawv cev hauv daim ntawv ntawm lawv cov khoom sau thiab kev sib txuas.

1. Teb kom tiav. Thaum ob peb cov khoom txuas nrog hauv kev sib kis mus dhau, tus uas ze rau qhov chaw muaj xwm txheej kub ceev.
2. Ib nrab. Kev tiv thaiv zoo ib yam li tag nrho, tab sis nws tsuas yog ua haujlwm txog ib qho nqi ntawm overcurrent xwb.
3. Ib Ntus. Thaum lub koob sib txuas nrog cov tib yam tam sim no tau teem caij sib txawv rau kev sib tw nrog nws qhov kev nce qib los ntawm qhov chaw nrog rau qhov tsis haum rau lub hwj chim qhov chaw. Lub sij hawm selectivity ntawm cov cav tov yog siv kom ruaj rau txhua tus shutdown ceev. Piv txwv: thawj zaug yog pib tom qab 0.1 thib ob, ob tom qab 0.5 seconds, qhov thib peb tom qab 1 thib ob.
4. Tam sim no. Selectivity yog analogous rau lub sij hawm, tsuas yog tus parameter yog qhov siab tshaj tam sim no. Cov cuab yeej raug xaiv nyob rau hauv cov kev taw qhia ntawm kev txo qhov teeb meem ntawm qhov fais fab mus rau cov khoom ntawm chaw thau khoom (piv txwv li, 25 A ntawm lub tswv yim thiab ntxiv, 16 A rau cov nyob thiab 10 A mus rau lub teeb pom kev zoo).
5. Lub sijhawm tam sim no. Hauv cov cav tov muaj lus teb rau tam sim no, thiab tseem lub sijhawm. Cov automatons raug faib ua pawg A, B, C, D. Rau lawv, nws yooj yim los npaj lub sij hawm xaiv nrog luv luv-luv (luv Circuit Court), vim tias cov cwj pwm ntawm cov cuab yeej siv sib txuas. Qhov kev tiv thaiv siab tshaj plaws yog tau los ntawm pawg A, uas yog siv rau cov hluav taws xob hluav taws xob. Qhov khoom siv ntau hom C, tab sis kev xav tsis zoo thiab qhov tsis txaus ntshai rau nruab lawv tsis pom zoo. Pawg D yog siv rau cov hluav taws xob tshuab nrog cov pib ua pauv loj.
6. Lub cheeb tsam. Kev khiav hauj lwm ntawm lub hwj chim kab sib chaws tau saib xyuas los ntawm ntsuas cov khoom siv. Thaum tus nqi teev ntawv teev rau theem pib (qhov teev tus nqi txwv), cov ntaub ntawv raug xa mus rau lub chaw saib xyuas, qhov twg qhov kev siv twj tua tsis siv neeg los tawm. Txoj kev siv nyob hauv kev lag luam vim nws yog qhov nyuaj, kim thiab yuav tsum tau siv cov khoom siv fais fab txawv. Cov koog hluav taws xob hauv koos pis tawj no yog siv: thaum muaj qhov kuaj pom, lub tshuab nqes ntws xa cov teeb liab mus rau siab dua thiab pib suav lub sij hawm luv ntawm txog 50 msec. Yog tias tus tes hloov hauv qab no tsis ua hauj lwm rau lub sij hawm no, qhov uas nws tau nyob siab dua cov saw hlau.
7. Zog. Tsis siv cov cav tov muaj kev kub ceev, vim cov luv luv-qhov tam sim no tsis muaj sij hawm mus cuag ntau kawg nkaus.

Hom kev xaiv

Lub selectivity ntawm kev tiv thaiv yog muab faib ua kev los yog tus txheeb ze, nyob ntawm seb cov khej twg raug kaw. Rau thawj rooj plaub, lub fuses ntawm qhov seem ntawm qhov Circuit Court yog feem ntau ntseeg tau. Qhov thib ob muab cov cav tov rau saum toj no, yog tias kev tiv thaiv hauv qab no tsis ua haujlwm rau ntau yam.

Selectivity ntxhuav

Selective tiv thaiv ua hauj lwm mas thaum tau siab tshaj lub nominal Circuit Court breaker kuv _n, t. E. Thaum uas tsis muaj accelerations. Nyob rau hauv cov ntaub ntawv ntawm luv circuits, nws yog qhov nyuaj ntau yam ua tau. Rau qhov kawg, manufacturers muag cov khoom nrog selectivity ntxhuav, uas nws yog ua tau los mus tsim cov pob khoom nrog selectivity ntawm kev lag luam. Ntawm no koj tuaj yeem xaiv tej pawg ntawm cov khoom siv los ntawm tsuas yog ib qho chaw tsim tshuaj. Cov rooj xaiv cov hauv qab no muaj npe hauv qab no, lawv tuaj yeem nrhiav tau ntawm cov websites ntawm cov tuam txhab.

Kev tshawb xyuas qhov xim nruab nrab ntawm cov kev lag luam thiab cov nqes hluav taws xob, muaj kev sib tshuam ntawm kab thiab kem, qhov "T" yog qhov xaiv tag nrho, thiab tus najnpawb yog ib nrab (yog qhov txhaum tam sim no tsawg tshaj tus nqi teev hauv lub rooj).

Muab xam cov kev xaiv ntawm automata

Cov kev tiv thaiv cov cuab yeej yog cov lus pom zoo, tsuas yog xaiv qhov uas yuav tsum tau ua kom yog los ntawm qhov kev xaiv kom yog thiab chaw. Lawv qhov kev txiav txim siab rau kev tiv thaiv, tsim kom ze rau lub hwj chim, los ntawm kev ua raws li cov lus hauv qab no.

• Kuv _s.o.posled ≥ K _nd ∙ Kuv _To.pr. , Nyob qhov twg:
  - Kuv _s.o.posled - tam sim no ntawm kev tiv thaiv yog cuab tam;
  - Kuv _To.pr. - luv luv tam sim no qhov kawg ntawm kev tiv thaiv cheeb tsam uas nyob ntawm qhov chaw ze tshaj ntawm qhov fais fab tuag;
  - K _nd - coefficient ntawm kev cia siab, nyob ntawm kev sib kis ntawm cov tsis.

Dab tsi yog lub selectivity nyob rau hauv cov kev cai ntawm automata nyob rau hauv lub sij hawm, yog pom los ntawm kev sib raug zoo hauv qab no.

• t ≥ t _{s.o.posled k.pred.} + Δt, nyob qhov twg:
  - t thiab t _{s.o.posled k.pred.} - lub sij hawm sib txawv los ntawm kev txiav cov cav ntoo uas tsis siv neeg, feem ntau nyob ze ntawm thiab nyob ze ntawm qhov chaw fais fab, yog cuab tam;
  - Δt - time selectivity kauj ruam, xaiv los ntawm catalogue.

Teeb duab sawv cev ntawm selectivity

Rau kev tiv thaiv tam sim no kev tiv thaiv ntawm hluav taws xob thaiv, yuav tsum muaj daim ntawv qhia selectivity. Nws yog ib daim duab ntawm lub sij hawm cov khoom ntawm lub cuab yeej ntsia nruab rau hauv Circuit Court. Lub nplai yog xaiv xwv kom cov khoom tiv thaiv ntawm cov cuab yeej cuab tam tau pom ntawm cov ciam ntsiab lus. Hauv kev xyaum, selectivity maps nyob rau hauv tej yaam num yog feem ntau tsis siv, uas yog ib tug loj drawback thiab ua rau fais fab tuag ntawm cov neeg siv.

Cov nominal piv yuav tsum muaj tsawg kawg 2.5 kom paub meej. Tab sis txawm tias lawv muaj ntau hom aav, albeit me me. Tsuas yog thaum piv 3.2 tsis pom lawv kev sib tshuam. Tab sis qhov no yog ib qho ntawm qhov tseem ceeb yuav ua rau siab dhau lawm thiab koj yuav tsum tau nruab ib qhov loj dua ntu tom qab lub tshuab.

Feem ntau, tsis muaj kev xaiv txog kev xaiv tiv thaiv. Nws tsuas xav tau yog qhov uas yuav tshwm sim loj tuaj.

Yog hais tias qhov kev sib tw ua rau hauv qhov tseem ceeb tshaj ntawm qhov nqi ntawm cov khoom siv, cov keyboards lossis cov keyboards tau muab nruab rau hauv cov tswv yim.

Koj tseem tuaj yeem siv tau tshwjxeeb uas muaj automata.

Selective tsis siv neeg S750DR

ABB manufactures khoom ntawm S750DR hom, qhov twg lub selectivity ntawm cov keyboards yog muab los ntawm kev ntxiv tam sim no uas tsis disconnect tom qab lub ntsiab hu tau tripped thaum lub sij hawm luv luv Circuit Court.

Yog tias qhov chaw txo xwm txheej tsawg dua, kev ncua sij hawm teb rov qab yog tsim los ntawm kev xaiv hu ua bimetallic. Hauv qhov no, txoj kev sib cuag tseem ceeb ntawm txoj kev hloov xim raug xa rov qab mus rau nws qhov chaw ntawm qhov kev txiav txim ntawm lub caij nplooj ntoos hlav. Yog hais tias tus overcurrent tseem ntws, tom qab 20-200 tawm lub thermal tiv thaiv nyob rau hauv lub ntsiab thiab ntu circuits raug kaw. Yog li xim bimetallic sawb blocks disengaging mechanism thiab lub caij nplooj ntoos hlav yuav tsis tau kaw rov qab mus rau lub ntsiab hu.

Qhov kev txwv ntawm lub tshuab tam sim no yog muab los ntawm ib qho kev xaiv resistor ntawm 0.5 ohms thiab ib qho loj ntawm cov hluav taws xob hauv lub tshuab ntaus sab.

Xaus

Dab tsi yog selectivity yog yooj yim to taub thaum xaiv cov hluav taws xob circuits nrog serial txuas ntawm automata. Nws tsis yooj yim los xaiv lawv kom paub tseeb tias cov kev xaiv ntawm kev sib tw tshaj. Txoj kev tshwm sim tshwm sim nyob rau hauv siab luv luv voj voog. Rau qhov no, ntau txoj kev siv, nrog rau ABB cov khoom tshwj xeeb automatic, uas tsim lub sijhawm ncua sijhawm rau kev khiav haujlwm.