Đang tải... (xem toàn văn)
HUGNQ PAN Q U A N I t S(f DUNG II HIEN TU0NG QUA TAI N G 4 N MACH VA TAC DUNG CUA CAU CHI (CONG NGHE LdP 8) Sich giio khoa Trung hpe cd sd theo chfldng trinh mdi (ldp 7 vi ldp 8) da thfle hifn dvtgc 8[.]
HUGNQ PAN Q U A N I t S(f DUNG II HIEN TU0NG QUA TAI N G N MACH VA TAC DUNG CUA CAU CHI (CONG NGHE LdP 8) Sich giio khoa Trung hpe cd sd theo chfldng trinh mdi (ldp vi ldp 8) da thfle hifn dvtgc nim, di qua nhieu ldp tgp huan cua bp mdn Cdng nghf ldp vi Vgt li ldp nhUng van cdn nhieu giip vien vi hpc sinh chfla hieu rd ve hifn tfldng qui tii vi ngan mgch, chfla hieu rd tie dyng cua eau ehi hoic aptomat mgch difn Bii niy xin trao ddi de ban dpe rd them ve hifn tfldng qui tii, ngan mgch vi tic dung eua eau ehi mgch difn ngin mgch, qui tii) thi cdc dung dien, thie't hi diin hi ddng diin ldn ndy ldm hdng Suy nghi tren chUa dung, chflng td chfla hieu ve hifn tUdng qui tii vi ngan mgch Gii sfl ed mgch difn nhfl hmh 1, mgch difn niy khdng ed eau ehi, eie bdng ddn tfldng trflng eho eac vgt tieu thy difn Neu sd vgt tieu thy difn niy nhieu qui, ddng difn mgch ehinh chgy tren eie dogn diy AB vi CD se ldn qui mfle thiet ke eua cic diy dan niy, Pham Dinh Cirong ehi, gia sfl hai diem M vi N bi ehgp nhau, difn trd dogn MN rat nhd, hifn tUdng gpi li ngan mgch Ddng difn mgch AMND rat ldn, ddng difn qua eae thiet bj difn hau nhu khdng cd (neu ed thi ddng niy eung rat nhd, dUdi ddng difn djnh mfle nhifu) nen khdng the lim hdng eie thiet bi difn dUde, ddng difn niy ehi lim hdng dogn mgch AMND Qua hai mgch difn tren ta thay ddng difn ldn mgch bj qui tii hoge ngan mgch khdng B A ~220V D (X) (X) (g) (g) M • B N C fv 220V DT K K H1 Ndi ve nguyen li lim vifc cua cau chi, cd SGK ldp viet: "Khi ddng difn tang len qui gii trj dinh mfle (do ngan mgch, qui tii), day chay cau ehi ndng chiy vi bi dflt (eau chi no) lim mgch difn bj hd, bio vf mgch difn vi cac dung difn, thiet bj difn khdng bj hdng" Cl cic ldp tap huan GV Vat H ldp vi Cdng nghf ldp tfl nam trfldc cho-den van cd nhieu ngfldi nghi rang neu khdng ed cau chi thi ddng difn tang len qua gia trj djnh mfle (do H2 hifn tfldng niy gpi la qui tii Nhflng ddng difn chgy qua eac vit tieu thy difn chfla tdi ddng difn dinh mfle eua cic thiet bj difn vi lfle niy difn ip dit vip thiet bj difn thap hdn difn ip djnh mfle syt ip ldn tren cic dogn AB vi CD Nhfl vgy ddng difn ldn qui tii se lim hdng cic dogn diy AB vi CD, ddng difn ldn niy khdng di qua cic thiet hi difn nen khdng lim hdng cae thiet bi difn dflde Cd mgch difn nhfl hinh 2, mgch niy eung khdng ed eau lim hdng cic dd dung difn, thiet bj difn neu mgch khdng ed eau chi vi ddng qua cic thiet bj difn van nhd hon ddng djnh mfle cua cic thiet bj GV phii eho HS hieu y viet SGK li: Neu mgch khdng cd eau ehi hoge aptomat mi xay qui tii hoge ngan mgch thi ddng difn mgch rat ldn lim chiy dfldng diy difn, neu chd chiy khdng dflp'e dap tat vi khdng cat difn se dan tdi chiy nhi, lfle ay khdng phai chi cd mgch difn vi cic thiet bi Nhdn bdi ngdy 2/2/2012 TAP CHi THlfr BI GlAO DUC - S6 78 - 2/2012 • 29 II Hl/OfNG PAN OliAN L t difn hdng mi toin bp dd dge khdng diing difn nhi eung bi hdng tat ca Vi vgy mgch difn phii CO ciu chi ho(K aptomat de xiy ngan mach hogc qui tii thi diy chi dflt hogc aptomat hogt dpng lam ddng difn mgch bi ngit de khdng bj chiy dfldng day dien vi chay nhi, eie thiet bi difn va dd dge tronj; nha khdng bj hdng Khi diy chiy cau ehi bi dflt thi thay day chiy vao cau ehi nhfl the nio eho thich hdp? Diy chi rat thdng thfldng nhflng xi hpi van cdn nhieu ngfldi khdng biet, ed ngfldi den efla hing dd dif n, cam vio diy chi dfldng kinh mm thay mem vi dflt dflt thi eho rang diy li diy ehi gii Hifn tren thj trUdng Vift Nam thfldng cd diy chi dudng kinh 1mm, 1,5mm, 2mm Ta dung diy Olmm cho mgch dung ddng difn tdi lOA, diy 01,5mm eho mgch dung ddng difn 20A, diy 02mm eho mgch dung ddng difn 30A Neu mgch chi dung bdng den hoge ti vi, ed ddng difn nhd thi dung bua dit mdng diy chi vi cit bdt mpt phan ehi di (diy chi mem nen dung keo binh thfldng cit de ding), chi de lgi Sdi ehi nhd thich h(?p vdi ddn^ difn cua dyng cy dung difn O cic ciu dao tdng hoge cau dao cho mpt khu vflc nio dd neu can ddng difn ldn thi ehgp cic diy chi vdi eho chju dflgfc ddng difn binh thfldng mgch de cd sfl ed thi cau chi dflt, dim bao an toin chd mgch difn nhi SODUNG Nliieu ngfldi nghi ring day clii de dim bio cho dyng cy dung difn khdng bj hdng klii difn ip cao qui djnh mfle lim ddng difn ldn qui ddng djnh mfle Thfle eie cau ehi mgch difn gia dinh ehi ed tic dung ngal mgch ngin mgch hogc qua tii, edn neu difn ip ldn qua djnh mfle lim ddng difn qua dyng cy dflng difn cd ldn gap ddng djnh mfle thi cau ehi cung khdng ngit mgch vi diy chi eie bing difn thfldng ldn hdn ddng difn sfl dyng mgch nhieu Khi mdi ddng mgch eho cic dyng cy ddt ndng hoac dyng cy cd dpng ed thi ddng dien ban dau thfldng ldn hdn ddng difn djnh mfle nhieu, vi the neu mgch difn gia dinh mi cau chi nhd chi chju ddng difn xap xi ddng difn djnh mfle cua cic thiet bj dif n mgch thi eau ehi ludn ludn bj dflt Trong mpt sd miy vi thiet bj difn mudn dim bio an toin ngfldi ta dung cau ehi dng de cd the ngit mgch difn ddng difn ldn hdn ddng lim vifc binh thfldng eua thiet bj difn Xin neu vi dy thfle te de giio vien tham khio: Miy qugt di de lim mat khdng phdng dung difn 220V 80W, ddng difn lim vifc binh thfldng ehi 0,3A nhflng miy lip cau chi 2A van hay bj dflt miy de liu khdng dung vi ddng khdi dpng cua ddng cd kha ldn -Qugt tich difn chgy acquy 12V ddng difn lim vifc binh thfldng vi ddng difn ngp dfldi 1A nhflng cau ehi 2A • TAP CHi T H I ^ BI GlAO DUC- s6 78 - 2/2012 qugt van hay bj dflt Trong mpt sd miy mde ngfldi ta dung ciu ehi dng de ngit mgch d ddng dif n vi nhift dp quy djnh theo tri sd ghi tren ciu ehi Vi dy: Ngfldi ta lap dp vao cudn diy cua bien the nhd hoic stato eua qugt difn mpt cau chi edghi 2A-130''C, cauchiniyed tie dung ngit mgch ddng difn d cupn diy bien the hay qugt tdi 2A hoic cupn diy cua bien the hay stato qugt ndng tdi 130"C Cf mgch difn ciia ndi edm difn binh thfldng dung gia dinh ngfldi ta lap mpt cau ehi ed de 10A-250°C, cau ehi niy ngat difn vio ndi cdm xiy ngin mgch ndi cdm lim ddng difn ldn hdn lOA hoic ndi cdm bi ndng tdi 250°C de trinh chiy ndi rd le d diy ndi khdng lam vifc Trong mpt sd may mde dat tien (miy photocopy logi cao cap) ngfldi ta lap song song vdi miy ben mpt ehi tiet nhd (kich thflde nhfl mpt tu gdm nhd) de bio vf miy Khi difn ip vio miy cao hdn difn ap quy djnh thi xiy ngin mgch lim cau chi nd, mgch difn vio miy bj ngit Khi difn ip trd lai binh thfldng, mudn miy hoat dpng lgi ta phii thay ehi tiet bao vf niy rdi mdi thay cau ehi va ddng mgch cho may lim vifc Vi vgy giao vien can phii cho hpc sinh tiep xue vdi thfle te de biet nhflng dieu thdng thfldng ddi sdng va ki thu^t,de hieu siu them bii hpc Trinh vifc hpc vit li chi hieu hdi hdt tren li thuyet, tiep xue vdi thfle te thi td Id md