DIEN THl/dNG THifC Q SINH HOAT THI/dNG GAP d MACH'DIIN Hoang HCTu Than I.C6NGTC(PHU nguyen nhan, neu khdng phli kiem tra cdng to Cdng to phu thUc chit eung la may dem dien nlng Sd dl chia b TrUdng hop chl mdt sd khlch cong to phu va chinh 11 viee q u i n hIng cd edng tP phu, mdi eong tP ly cdng to Theo dieu le cung d p v l sd phu d n eong vao chi sd - 5% de bu dung dien, mdi hp dung dien la khach lupng tdn that tU cdng to chinh den hang cua dpn vj cung Ung dien Tren cdng to phy Sd cdn lai: ed sd hop ddng, don vi cung Ung dien W^ = W^-(1.02-I.05}SW_[2) se eho khlch hIng thue eong td Od I I edng to ehinh Ke tU cong tP chinh se khlch hang khdng co eong trd len tdi mang dien chung don vj tP phy chia tra tien cung yng dien quan ly TU sau cdng t d Oat cong tP phu can t u i n theo ehinh trd di thupe quyen quin ly khai qui tae dat eong tP, eu the la : thac eda hd dung dien Thuc te cd the cd nhieu khach hIng dung dien ehung mot edng to ehinh Khi dd, de d e ddn vi khlch hIng se cung t r i tien dien duac cdng bang, mdi khlch hIng can cd mdt cdng t d rieng, gpi la cdng t d phu Phln biet hai trudng hop : a Neu tat e l khaeh hIng deu cd cdng to phy, viee phan bd chi sd cdng tPtinhnhUsau: - Cong t d phai dupe ddn vi cd chUc nang kiem tra va kep chi - Dly ty ngudn vao edng to phai la day d p ehi hoac d p lUC, d p ABC, day du-p!ex,,, dam bao khong the lay dien trudc cdng to, - Sau b i t dly, day nap vd ehe kin va kep chl - Dinh ky kiem tra lai dp chinh xle eua eong tP XLJr LY DI$N A P C A O VA THAP ddly, W^,|^ - sd dien nlng ddn V! khlch hang thy i phai t r i ; Vi/^ ehi sd cdng td chinh; 6u goi la lech dien dp Tat e l d c thiet bi dien deu co the lam viec vdi dp lech dien ap cho phep Neu lech nam gidi han -W% £ du £ +5%, thiet bi dien lam viec binh thudng, Ra ngoli pham vi dd, phli eoi la khdng binh thudng Xet hai trudng hop: Dien dp cao • 06 la trUpng hop du> 5% Oien ap eao se dan den d c hau qua sau: i Tang ddng dien lam viee eua thiet bl, do, lam tang tdn hao, gay ndng qua mUe Dae biet, vdi cac thiet bj dung dien cap nhiet nhu md han, bep dien, ban la, hole den spi ddt, den dien tU, , eong suat ti le vdi binh phuong dien ap Neu dien I p tang 5%, cdng suat tang 10,25%, dien aptang 10%, eong suat tang 21% Ket q u i la thiet bj gia nhiet qua mUe, de gay chay hdng li Tang t y thong Idi thep v l dd, t i n g tdn hao loi thep Ton hao ti le vdi binh phuang dien ap Cac thiet bj cd Idi thep nhu bien ap, cuon chan luu, cac loai dong CO, se bi ddt nong qua mUc Mdi thiet bj dCing dien deu dupc thiet ke vdi dien ap nhat dinh, goi la Tdm lai, dien ap cao, d c dien dp dinh mUc -U^, Oien I p djnh W^ - chi sd cdng t d phu ciia mUc eua thiet bj phli phu hop vdi d p thiet bj se l l m viec manh len (den khach hIng thy i; SW^ - tdng chi sd dien ap ngudn eung dp.Trong mang sing hdn, bep ndng hon, ddng cd elc cdng to phu; dien sinh hoat, d p phd bien la 220 V quay nhanh va khde hon), tieu thu nhieu cdng s u i t hon va cung bi ddt Ve ly thuyet, tdng SW, p h l i bIng Thuc te, dien ap mang eung ndng nhieu han, d i bi hdng d c h W^ try di lupng ton that tren mang tU d p thudng sai khle it nhieu so vdi dien, g i l m tudi tho v l cd the bj cdng to chinh den elc cdng t d phy dinh mdc Goi U,^ la dien I p thuc dat ehly hdng Do cd sai sd, nen neu tinh ra, ti sd W/ vao thiet b i , t y s d : Dien dp thap: Od la trudng hap IW^ =1,02+0,08 la cd the chap nhan 6u = (U,^-UJ/U^{3] du < -10%, tye la dien apthUc dudi dUdc Neu sai lech qua Idn, d n tim Dien Jk Doi songl 25 S DIEN THl/dNG THtfC 10% so vdi djnh mdc Oien I p t h I p d i n d^n cle h l u qua sau : 1, Gilm tinh nang l l m vigc ciia thidt bi, nhU d^n k^m sang, bep dien, md h i n k i m ndng, ddng cd g i l m tde dd, lue keo yeu, ,., Cung theo qui l u l t ehung, didn I p gilm, cong suit eiia den, b i n I I , g i l m binh phUdng l l n , mo-men quay cua ddng cd cung g i l m binh phuong l l n , Ket q u i ta thiet bj dien khdng thuc hidn dUpe chyc nlng CLia minh (den khdng du sang, bdp khdng dun sdi nUdc, mo han khdng ehly thidc, quat khdng dii mIt, ,,), U^ = U^ + U^ = 2U^{4) - N^u hai p h l n d I u spng song (hlnh b): Vly chuyen tCfsong song sang n6i ti^p, diin dp dinh mCfc tdng gd'p ddi cdn ndu chuyen ti/ n6i tiep song song, di^n dp dinh mite gidm cdn rndtnCta ii Vdi cle dong co k^o miy cd md-men d n it thay ddi nhu tu lanh, m i y dieu hda, m i y khIu chay dien, bdm nude, dien ap gilm, ddng dien se t i n g len Ket q u i I I dong Cd bi qua t l i , cuon day bi ddt ndng qua mUc, Ngoai ra, neu dien ap gilm nhieu, dong ca ngUng quay hole khdng md may dUde, rat nguy hiem, iii Mdt sd thiet bj dien td l l m viec vdi ddng di^n ty, neu thudng xuyen lam viec vdi dien I p thSp, ddn rIt mau gia coi Den ong lam viec vdi dien ap thap rIt mau den dIu, De giU lech dien I p pham vi cho phIp, ta dung bien ap dieu ehinh hole dn ap, Khi dd can cd bien phap de phdng dien ap cao va thap, Hinh - D6I ndi song song - ndi tiep Caeh thay ddi d p dien I p cua ddng eo nhu sau: Trudng hap :Odng co 220 V dung d mang llOV.Md D O N G T H I ^ T B! dCAPDI^N AP K H O N G PHU HOP dong cP ra, thay hai phan d I u ndi tiep vdi (trudng Oien ap eua thiet bi dung dien phai phu hop vdi dien hdp ddng ca 220 V cd tat c l d e cuon d l y dau dIu song I p ludi d p Trudng hop dien ap dinh mUc khdng phu hpp song hau nhu khdng gap), Khi dd chuyen hai phln tif ndi vdi d p dien ap mang dien, phai y.(s ly, Thudng gap d c tiep t h l n h song song, se cd ddng co 110 V Xet hai trudng trudng hpp sau : hpp thudng g i p : i Cap dien ap mang la 110 V, dien ap thiet bl la 220 V, Khi dd d n cd bien phap g i l m U^^ cua thiet bi di mot nda hoac tang gap d6i dien ap ngudn ii Cap dien I p mang la 220 V, dien ap thiet bi la tlOV, Khi can g i l m dien I p mang di mot nda, hole tang U^^ ciia thiet bl len hai Ian lii Thiet bi eo dien ap thap nhu6 V, V, 12 V, 24 V, van mudn sydung vdi dien ap lOV hay 220V, Caeh tien dung nhat la diing on I p hay bien I p dieu chinh tao cac dien ap d n thiet, thda mIn yeu cau sy dung, Tuy nhien, viec dung tryc tiep dien ap mang van la d c h tien Idi han, Sau day se gidi thieu mdt sd bien phap chinh CO the ap dung mang dien gia dinh, a Doi noi ddy ben thiet bj i Doi not cuon day song song - noi tiep dong co vong chap hay cdc thiet bi cd nhieu cuon ddy Trong thUc te, sd bdi day d ddng eo vong chap bao gid cung la sd ehin, hai hoac la bdi sd eua hai bdi (4,8, bdi) Oem chia so bdi hai phan va gpi dien I p djnh mdc moi phan la U , dien ap dinh mdc eua dong cd la Ug, se cd: - Neu hai phan dau ndi tiep (hinh la), dien I p ddng 26 I ^/fn ^ t^ song d^=H, So/7^ sang Hinh - Doi n6i dau dong cd c6 hai boi ddy Ddng cd co hai boi ddy ddu noi tiep, danh dau bdn dau day cua hai boi nhu hlnh 2a (chd ndi lien hai bdi, gpi dau thudc eudn la X,, dau thudc cuon la A^), cat eho ndi, dem X, dau vdi X^, A^ dau vdi A, Hai dau d l y II A, va Xj nhu eu (hlnh 2b), Ddng caco bon boi day (hinh 3a), eoi hai bdi ndi tiep la mdt phan (phan mdt gom bdi +2, phan hai gdm bdi 3+4) va tien hlnh gidng nhu tren (coi A , - X j l a e u p n IjA^-X, la eudn 2}.Thlo mdi ndi X^ - A3, dl'u X^ - X^, A^- A,, hai dau day r a l l A , , X , nhucu(hlnh3b), DIEN THI/dNG THl/C 220 y Hinh - Doi noi ddu ddng ca cd bSn bdi ddy Q trUdel, mdt g e j » ' ' v l q u a t lam viec binh thudng theo so dd trudc Vi hai mach d I u ndi tiep, nen cd the dau vao dien 220 V, dien ap trdn mdi cuon van chi xap xi 110 V Khi thyc hien d n lUu y chon C = (1,5-2)C sd hinh 5a Ching han, n^u tu C = 8mF, C = 12-16mF, cdn neu C 4mF, C = 6-8mF Khi ddi ndi, cho ddng ca lam viec v l ddng dien qua cuon lam viee, bIng xap xi nhU so dd cu la dat, TrUdng hop khong dupc ddng dien, thuc hien dien ^p tren eudn l l m viec (dien I p giUa hai d I u AI - XI tUe hai d I u R-C) ndu xap xi 110 V (bIng nda ngudn dien I p ngudn la 220 V) la tdt Neu thap hon 110 V, tUc ty C'cdn hai b l , nguoe lai, neu cao hon 110 V, tyc tu C hdi Idn Khi d d d n thay doi C Trudng hap : Odi ndi ddng cd 110 V 220 V Trudng hpp chi thuc hien dugc ndu ddng cp 110 V cd d c eudn d l y dau song song Mudn ehuyen sang 220 V, ta ehi viee ddi sang cIch dau ndi tiep, CIch thye hien la q u i trinh ngUpe vdi tren d l y (ddi tU so dd b sang sP dd a dhinh2va3) o^- u^ Hinh - Chieu dong dien cdc boi ddy Neu dong eP 110 V ed d e day dau ndi tiep nhau, khdng ddi t h l n h 220 V dupc Chu y: Khi doi cdch ddu ddy, cdn dam bdo chieu dong dien tUng boi khong thay doi so vdi trUdc Muon the, chi cdn kiem tra Id canh hai boi lien ndm cung mot khe cuc co chieu dong dien gidng Dieu ndy duac minh hoa tren hinh b Doi noi ddng ca qugt chgy tu Dong cd chay tu gom ed hai cuon dly, eudn l l m viee Aj - X, v l eudn md m i y Aj - Xj Hai dau X, - X^ dau dau chung C, cdn dau A, dUa la dau l l m viec (R), dau Aj la dau md m i y (S) CIch dau d l y binh thudng cua dong eo ve tren hinh 9.5a va thi vee-td tren hlnh 5b Ty m d m l y C ndi tiep vdi dau md m i y S, dau chung vdi dau lam viec R, dau v i o d l y pha A Dau chung C dau v i o d l y ngudi X, Ddng dien I, cham pha sau U, cdn ddng 1^ cd tu C, nen vUdt pha trude U Ket q u i gdc lech j giUa I, va 1^ xap xi 90° (hinh 5b) v l dd, tao md-men md miy Neu quat ehe tao vdi dien I p llOV, d n dau vao mang 220 V, ndi chung, khdng can quan lai day, rat tdn kem, ma cd the thue hien so dd d i tien ve tren hinh 5e CIch thye hien nhU sau Td dau day ehung C, dau tdi tu C, rdi tdi dau md m i y S, dau tdt d l y ngudi X Cdn dau l l m viec R dau v i o d l y pha (A) Ddng 1^ II tdng cua ddng 1^ qua eudn md miy v l ddng 1^ qua ty (hlnh 5d) Ddng 1^ theo qui dinh, di t y Aj tdi X^, nen se bIng -1^ Ket q u i , I, van vUdt Hinh - Doi noi dong cOqugt chay tutUllOV thdnh 220 V a) Ddu chay liOV(sad6 chinh qui), b) Do thi vec-totuang Ung vdi mach chinh qui c) Ddu chgy 220 V (so coi tien); d) Do thi vec-ta Ung vdi mach dd cdi tien Tu Ceo the t i n dyng ty Ceu va dau song song them mot tu mdi Neu cd dieu kien, nen thay the han mot ty C mdi cd trj sd dien dung thich hpp, dien I p cho phep tU 150 V trd len de ddng cP quat l l m viee an toln CIc ly luan tren d l y neu vdi ddng coquat v l cd the I p dung cho ddng co mdt pha ndi ehung Hinh - Ddu noi tiep qugt nOVvditu dien demac vdo dien dp 220 V Dien Jk Doi songl 27 £] DIEN THCdNG THt/C c N6i ti^p tu diin vdi qugt 110 V, dd'u vdo diin 220 V Ghi chCi: D^ fy C phdng di^n tich du, cdn mdc vdo hai ci/cti^m0tdl^n trdR= 100-300 kW, I-2W Cleh mic ve trdn hlnh 6, Sd dd thay th^ tUdng dUdng ve tren hinh 7a, dd quat dUde thay bdi dl^n trd r v l NHOTNG H I / HdNG THdNG THl/CTNG MACH dien d m L Gpi j II gdc pha cua quat, g i i sCf II dl§n I p d | t DI£NGIAD)NH v i o quat d n dat U^ = 110 V, tU dd, d c t h l n h p h l n U^ v l Mach di^n gia dinh cd nhyng hy hdng chfnh I I dift U, tren quat I I : m^ch, ch|p m^ch / rd di^n v l q u i t l i U =L/^cos/;^ SI/c6 din mach Vdi quat, cd thd lly cosj_^= 0,8 TU d d : Dirt maeh I I hi^n tUdng didn bj n g i t d mdt chd v l U=O.BU =0.8xnO = 88V dd, khdng cd ddng didn qua thidt bj dung di^n NhUng nguydn n h i n thdng thudng I I : Nd elu chl ho$c CB tic ddng elt mach Oien I p mang U gdm hai t h l n h p h l n U, v l U^, vdi U_ I,-U^.Tyhlnh7b: ii.MdinditidpxucxIu iii Tudt d l y khdi eye b i t dly, U = ^L' -L': = V22(r"^^l