BotroKienthucLuyenthiDaihocTrenkenhVTV2VatlyPhan2DienxoayChieu p2

L = - H => Chon B 1007rt + - - (A) ' , ^ « p ,(,ji tan so 50 H z Ban dau d o lech pha giira dien ap giCra hai dau mach va d o n g dien la 60" t h i cong suat tieu t h u mach la 50 W Thay d o i C de dien ap giira hai d a u mach c u n g pha v a i i thi mach tieu thu cong sua't la U'»i(b./t P = UI cos CP = — c o s ^ ^ > = ^ ^ = R P| C W Hitoitg dan ' ' • D 120W •,,U.l>l' - ri J i}i f T O ^ ri'>i>m 'fia'"., song v o i t u d i e n C i thi d o n g dien mach la i2 va cong suat tieu t h u la P2 Biet P I = 3P2 va ii v u o n g pha v o i i : Xac d j n h goc lech pha cpi va (p2 giua ^ P2 = P, cos (pj >•• • C i t h i d o n g di^n t r o n g mgch la i j va cong sua't tieu thy la P2 • ^^'^^ ^2 P i va i , v u o n g D 480W Huaitgdan noi tie'p v o i t u dien c6 dien d u n g C thay d o i K h i C = C i d o n g dien 60 ' ' ! ' ( ' • D (pi = -7r/4 va (p2 = 7t/4 Huang yj3 if;tb , D ' j ^ i • Chiiy: Kcl hap }(•• noi tie'p v o i tu dien co dien d u n g C i K h i d o d o n g dien t r o n g mach la i i va C (pi = 7i/4 va (p2 = - i / va t u d i e n co dien d u n g C thay d o i dugc D i e n ap d a t vao hai dau mach c6 B 0 W I • y-i" V i d u 8: Dat dion ap xoay chieu on d j n h vao hai dau doan mach g o m cugn day dien ap hai dau doan mach v o i ii va i2 V i d\ 6: Doan mach xoay chieu g o m dien tro thuan R, cugn day t h u a n cam L A l O O W = V3 71 => Chon C A tpi = t / va (p2 = - i / tan cp = ui u cong sua't tieu t h u cua mach la Pi Lay mc)t tu dien khac C = 4Ci mac song cos"(p=>(n = — R too P = I - R ^ 0 = I-'.100=?>I= l A M - -''^ ' ' ' 'p' 'iK/I C o > C i = > Z c < Z c i =>(p2 - 'PI = T = = ^ ^ = l + ^ Vtft r Huang dan Vv Gia t r j L i cua cuon cam va bieu thuc c u o n g d o d o n g dien qua mach dirge xac d i n h '^^'•^ A I g n s j b ti^- B (pi =-7r/6 va (p2 = 7i/3 C (pi = -7t/3 va (p2 = n/6 •fiîikf.U> v.240 = P,,„g haChonB .final} i=fy.^ ^ ^ iJi'if 61 Cty B S trp kiSn thitc V^t It LTDtl tren kenh VTV2 t^p - Chu Vitn Blen Huang V i d u 10: T r o n g m o t mach dien xoay chieu g o m m o t d i e n t r o t h u a n mac noi tiep v o i m o t tu dien D i e n ap hieu d u n g dat vao doan mach la 150 V, d o n g dien chay t r o n g mach c6 gia t r i hieu d u n g A D i ^ n ap h i ^ u d u n g g i i i a hai ban tu d i e n la 90 V Cong suat tieu t h u ciia doan mach la A 200W B W C W = U K + U c =>150 =UR+90^ ^ HV7:) D 270 W Huang dan U ' doan mach g o m tu C n o i tiep v o i cuon day t h i dien ap hieu d u n g tren t u la 100 V S V va tren cuon day la 200 V D i e n t r a t h u a n ciia cuon day la 50Q C o n g suat tieu t h u d i e n ciia doan mach la: ' '' " C 120 W Huang tancp = DVVH Khang Vipt dan = 200(Q) ; U = tan - => Uj = Uc = U , = H ( V ) U ' = U?+(U| -Ue)^ = 0 ' V i d u 11: Dat m o t d i e n ap u = 100 V2 coslOOnt (V), (t d o bang giay) vao hai dau ' coC MTV U,=100(V) H UR =120(V) B 100 W = , P = I^R = I U K = 240 ( W ) =^ Chon C A 150 W = ' ;; Zr Tisnn I = Zc 2V3 P = l'r = •t) ^ r = ^ = 200^/3 (Q) = -V(A) 200V3 * 28,9(W) => Clion B V i d u 14: M o t mach d i e n xoay chieu noi tiep g o m tu dien c6 d i ^ n d u n g C, dien D 200 W tro t h u a n R va cuon cam t h u a n c6 cam khang 80 Q D o Ion he so cong suat dan ciia doan mach RC bang he so cong suat ciia ca m a c h va b a n g 0,6 D i e n t r o t h u a n R CO gia t r j B.30(Q) A 50 (Q) => 100^ = 200^ + 3.100^ - 200V3.UL U, =100V3 [ U , =100 , =>P = I r = — ^ = 200{W)=>ChonB r " ^'' d a u doan mach RLC no! tiep cuon day thuan cam c6 L = 0,l/7t H t h i tli d i e n ap hieu d u n g tren t u va tren cuon day bang va bang 1/4 d i e n > ^ hieu d u n g tren R C o n g suat tieu t h u tren mach la B W - R COSCPKC = : = 0,6 Zc =0,5ZL =40(Q) R = 30(Q)=:>Chon B = 0,6 =U, D 120W • Z'^^î^J a hai dau t u d i e n 120 V H e so cong suat ciia mach la A 0,125 B 0,87 C 0,5 Huang dan U2=U^+(UL UC)'_ Mach cong hUdng => I = — p = I^R = — = 360(W) => Chon A R • ' * ^ ' C = 0,1/K (mF) Dat vao doan mach dien ap xoay chieu u = 100 V2 cosSOnt (V) thi thay d i e n ap g i i i a hai dau cuon day sam pha h o n d o n g d i e n t r o n g mach la 7t/6, d o n g t h a i d i e n ap hieu d u n g tren cuon day gap d o i tren t u dien Cong suat tieu t h u ciia doan mach la B.28,9W C 240 W ^c=^la=^l+î coscp = /f d u 13: M o t doan mach g o m cuon day no'i tiep v o i t u d i e n c6 d i e n d u n g A.200W ( r i ' r i ' j i b i/2 cos(1007rt - n/6) V v i A.360W Huang if!> D 100 (Q) C.67(Q).' D.57,7W U U 'I'lOr i : '1 , t j - ,JS + jl202=u|+(UL-120f ll202=U|+u2 ; = 0,87^ ' D 0,75 ' Chon B ' M i , , , viLi' |UL=60.1:? U K = 6OV3 «'lU f!;,Ue ,; «!•(•' r'^•.f Z, =coL = ( n ) ; Z e = — = 100(Q) wC - = ^ + 25-+ U , - U , 75 + 75f U , =20(V) Up + U [ U , - 15{V) ,,i ^ \ • U ' • • ( îJ ,1 P = 1'^R = " *• » , , -R = R = 40(D) - 200R + 6400 = : 200r2R R^ +(20-100)^ 400 = R^+(Z,-Zc)^ R = 160(Q) V i d u 17: D o a n mach dien xoay chieu mac no'i tiep g o m tu ctien, dien t r a t h u a n Chon D ^ >iH va cuon cam t h u a n D i e n ap hieu d u n g hai dau doan mach va tren cuon V i d u 20: D a t vao hai dau doan mach m o t dien ap xoay chieu co gia t r i hieu cam Ian k t o t la 360 V va 212 V He so cong sua't cua toan mach coscp = 0,6 d u n g 200 V D o a n mach g o m cuon day co dien t r o t h u a n R co cam khang D i e n ap hieu d u n g tren tu la A 500(V) ! , , , , , , A , , r.: ^ r^:' m cos(p = ^ B 200 (V) -O' ^ C 320 (V) " ' ^ = 0,6=Û|, =0,6U = I ( V ) - " S , D 400 (V) , , ,,5,^ „ 140 Q mac n o i tiep v o i tu dien co d u n g k h a n g 200 Q Biet cong sua't tieu t h u tren mach la 320 W H e so'cong sua't ciia mach la B 0,6 hoac 0,8 A 0,4 Huang ill >,n,'r*^nit\ (bi U - = Uf, + ( U | - U^.)^ => 360- = 216- + ( 2 - U(.)- ^ Z, =a)L = 140(Q);Zc = P = 1^R = - ^ R = V i d u 18: Doan mach dien xoay chieu mac no! tiep g o m tu dien, dien t r o thuan mach va tren tu Ian l u o t la 300 V va 140 V D o n g dien mach tre pha so voi dien ap hai dau doan mach va he so cong sua't cua mach coscp = 0,8 C 3,2 ( A ) D (A) Humtgdan U- = Uf^ + ( U | - U e ) " ^ 300- =240- + { U , -140)- =>U| = ( A ) ^ Chon A R "''t' =320(V) ^'5'" = 0,8 •ChonB !r:,M V i d u 21: D a t vao h a i dau doan mach m o t dien ap xoay chieu 100 V - 50 H z I/TI ( H ) va tu dien co d u n g k h a n g Zc Biet cong sua't tieu t h u tren mach la 100 W va k h o n g thay d o i neu mac vao hai dau L m o t ampe-ke co dien t r o k h o n g d a n g ke Gia t r j R va Zc Ian luc^t la A.40i^va30Q B Q v a Q u = 400cos(1007rt) ( V ) M a c h AB g o m cuon day co dien t r o t h u a n R co d o t u cam 0,2/7: ( H ) mac noi tiep v o i tu dien co dien d u n g 100/K (HF) N e u cong : U^R 100^ R p R'^ + Z,c rZc=50(Q) R = 50(Q) C Q v a a R^+Z^ D 20 Q va 50 Q dan 100-R '""""R^ + (Z,,-ZC)^ V i d u 19: Dat vao hai dau ctoan mach A B m o t dien ap xoay chieu: sua't tieu t h u R la 400 W t h i R bang - 125R + 3600 = = 0,6 Huong • R ^ + ( Z , - Z J - • + (140 - 200)^ Chil y: NCni hict cCm;^ siid't tiC'u thu trcii toan mach de tinh dien tnr Iioac cos(p ta dim vao con;^ thu'c: P = l~R = R^ +(140-200)^ D o a n mach mac n o i tiep g o m dien t r o t h u a n R, cuon cam co d o t y cam L = Z, >Z^-=>U| >Uc;coscp = - ^ = 0,8 =i.U|, = , U = 240(V) ^ Zi D 0,75 ;7t iJfi? v/.ni I f i u a ^/.no'j t'>::ci 2001R => 320 = R^+(Z,-Ze)^ R = 45(Q)=> coscp = C u o n g hieu d u n g d o n g qua mach la B ( A ) dan R R R = 80(Q)=> coscp = — = Z yJR^ +(140-200) va cuon cam t h u a n co cam k h a n g 80 Q Dien ap hieu d u n g a hai d a u doan A (A) C 0,45 hoac 0,65 ^ = 200(Q) coC U-R =500(V) Chon A 64 i,v.:io!: Huong dan + Uf ) + Uf, + 2U„U, - 2U, Ue + U^^ Vift = 100 R2+(100-ZJ^ = 100 U ^Jl'nwtl Mach dien liic dau > Chon B M a c h dien sau 65 Bo tip hien thiic Vpl li LTDH Cty VTV2, t^p - Chu Van tren hSnh V i du 22: Dat vao hai dau doan mach AB mot dien ap xoay chieu 100 V - 50 Hz Mach AB gom cuon day c6 dien tro thuan 20 Q c6 cam khang 60 Q mSc noi tie'p voi tu dien c6 dung khang 20 Q roi mac noi tiep voi dien tro R Ne'u cong suat tieu thu R la 40 W tiVi R bang A Q B 10Qhoac200Q ' ;i;:,-OfJL C 15^2 hoac 0 Q • i^'iU T2T, PR UÔ r.^; : D 20Q • Huong dan ,\) ->\s U^R =r R = — R = => 40 = (R + r)2+(Z, - Z c f R2 -210R + 2000 = 0=> J- s , (R +20)2+(60-20)2 R = 10(Q) ,:,vyb => Chon B R = 200(Q) ^ = - ^ = 0,5(A) ^'^ U j 120 -2 ^ — = * / ( R d + r)^ +(1007rL)2 = — tie'p, dien ap giua hai dau doan mach u = 50 \/2 coslOOnt ( V ) Dien ap hieu V Bie't cong suat tieu thu mach la 20 W Gia tri R bang , = U | + ( U L - UC)^ p = I2R = 2K-.R C 15Q Huong dan ^ D Q - ,X tieu thu cua doan mach la A.240>y'3W Cdchl: C 240 W u = 120sin 1007rt + - j = 120cos lOOnt-V D 120>/3 W • 3; 6, (V) i = 4cos 100TUt + - ( A ) 6) UR = 40(V) \ Cdch 2: Goi i* la so phuc lien hop cua i thi cong suat phuc: P = - i u = 120 - 207,85i => P = 120(W) ^ Chon B 4Z- V i du 24: Mot mach dien xoay chieu gom dien tro R noi tiilp voi cuon day c6 6J dien tro Q Dat vao hai dau doan mach dien ap u = 40 ^/6 coslOOTtt ( V ) , (t (Phan thuc cua cong suat phuc la cong suat tieu thu phan ao la cong bang giay) thi cuong dong dien cham pha hon dien ap giua hai dau suat phan khang) doan mach la Tt/6 va cong suat toa nhiet tren R la 50 W Cuang hieu Thao tac ba'm may tinh: sau nhap - '-i";*') dung mach la: A A hoac A \'d B A hoac A V sau ba'm dugcketqua 120-207,851 ' I = 1(A)' I = 5(A) mac no'i tie'p voi mot UAD = 100 V2 cos(100nt + nil) ( V ) ; um = 100 76 cos(1007it + 2TI/3) ( V ) va i = V2 cos(100r!:t + 7T/3) (A) Cong sua't tieu thu cua doan mach AB la A 173,2 W C 0,639H D 0,636H Htiatig dan Khi den sang binh thirang thi cuong dong dien chay qua va dien tro thuan cua den: ?in-: i i iiK 220 V - 50 Hz, thi den sang binh thuong Do t u cam cuon day la: B 1,15H ,, • : thoi tren cac doan mach va dong dien qua chung Ian lugt c6 bieu thuc: Chon A bong den 120 V - 60 W Noi hai dau mach dien voi nguon dien xoay chieu ~r::::Z 7: 120Z Vi du 27: Doan mach AB g5m hai doan A D va DB ghep noi tie'p Dien ap tiic Huong diin V i du 25: Mach dien gom cuon day c6 dien tro thuan 10 A 1,19 H ba'm IshiftlfUfzll^ ' • C A hoac A D A hoac A UIcoscp = PR + I^r ^ 40V3.1.— = 50 + I^.IO 66 B.120W • 20 = — =^ R = 80(Q) =^ Chon A R V / R2 ' P = UIcoscp = 60N/2.2>/2 C O S — = 120(W) =:> Chon B \ ^ 50^ = U ^ + (30 - 60)^ Chon B thi dong dien mach c6 bieu thuc i = 4cos(100TTt + nib) (A) Cong sua't dung hai dau cuon cam va hai dau tii dien Ian lugt la U L = 30 V va Uc = 60 B lOQ L «1,15(H) Huang dan V i du 23: Mot mach gom co dien tro R, cuon cam thuan L va tu dien C mac noi A 80Q yj^ Khang Vi du 26: Dat dien ap u = 120sin(1007Tt + TT/3) ( V ) vao hai dau mot doan mach lOO^R J TISnn MTV own Bien B 242 W - )i , C 186,6 W D 250 W ' Huong dan Eîen ap tong: u = L I ^ D + " D B Cong sua't phuc: ,'•'1 u = ^^72Z-1 flO072Z- + 100V6Z—1 = 173,2 + 2001 3; I 3,J ^ =>P = 173,2(W)=>ChoiiA • " = -1 , / u:, , ' xHtK^: - : v : a 67 Cty Bd trp hien thiic V$t IIL TO I I trcn k&nh VTV2 t^p - Chu Via M a c h no'i tiep chua tu cho d o n g xoay ^ chieu d i qua n h u n g k h o n g cho d o n g , | i | voi ' 1 = - Z L =50%/3(Q) +Z Nguon xoay chieu (RLC): Zc = V i d u : ( D H - 2012) K h i dat vao hai dau m o t cuon day c6 t u cam 0,4/7i (H) (oC = 36,6(Q) U^R 100^50 R2+(Z|-ZC)^ 50^+(50V3-36,6) aOO(W)=^ChonD 0,4 ( A ) Sau do, thay hieu dien the bang m o t dien ap xoay chieu c6 tan Vi dii 4: (DH-2009) K h i dat dien ap k h o n g d o i 30V vao hai dau doan m?ch g o m so 50 (Hz) va gia t r i h i ^ u d u n g 12 (V) thi c u o n g d o d o p g d i e n hieu d u n g qua dien t r o thuan mSc noi tiep v o i cuon cam thuan c6 t u cam 0,25/Tt (H) t h i cuon day bang : d o n g dien t r o n g doan mach la d o n g dien m o t chieu c6 c u o n g d p A Neu A 0,30 A B 0,40 A i^ v i ; : ; " u C 0,24 A ' - • ' D 0,17 A Huangdan dat vao hai d a u doan mach dien ap u = 150 V2 cosl207rt (V) t h i bieu ' thuc ciia c u o n g d o n g dien doan mach la • ,v«t nail ' j u d q R = — = 30(Q) ' ' A i = 5N/2cos(120Tit-7t/4)(A) B i = 5cos(1207tt + 7i/4) ( A ) C = 5^/2 cos(1207it + 7t/4) ( A ) D i = 5cos(1207rt- 71/4) ( A ) i' Huong dan Nguon xoay cliieu : Vi :UV- , h = •I R-+Zf = 12 , ^ = 0,24(A)z=>ClionC V30-+40- Mac vao nguon chieu : R = y = 30 ( f i ) d u 2: Dat vao hai dau cuon day co t u cam L = 0,35/7i ( H ) m o t dien ap Z L =coL = 30(Q) k h o n g d o i 12 V t h i cong suat toa nhiet tren cuon day la 28,8 (W) N e u dat Mfic vao nguon xoay Chieu : Z = vao hai dau cuon day dien ap xoay chieu c6 tan so 50 H z va gia t r i hieu •' d u n g la 25 V thi cong suat toa nhiet tren cuon day bang bao nhieu? • A 14,4 (W) B.5,0(W) C.2,5(W) Nguon chieu : Pi = — => R = — = 5(Q) • : • V -Silt • Nguon xoay chieu: ' 'Z| =a)L = 35(Q) P, = U^R = R-+Zl 5^+35^ = , ( W ) =^ Chon C du 3: Dat vao hai dau ong day m o t dien ap m o t chieu 12V thi c u o n g d o n g d i e n t r o n g o n g day la 0,24A Dat vao hai dau ong day m p t dien ap xoay chieu c6 tan so 50 H z va gia t r i hieu d u n g 100 V thi c u o n g d o n g R ' •••SI/ = 30V2 ( Q ) !(, = = 5(A) = !=:>« = — > : u sdm pha hdn i la — i = 5cos 1207rt - - ( A ) => Chon D V i d u 5: Dat dien ap xoay chieu c6 gia trj cue dai Uo vao hai dau m o t dien tro thuan R t h i cong suat tieu t h u la P K h i dat vao hai dau dien t r a m o t hieu S + zl tancp = D 28,8 (W) Huattg dan Vi r j p i - UWJrKnang dien hieu d u n g ong day la l A Mac mach dien g o m ong day noi hep 2) Mach R L mic vao nguon mgt chieu roi mic vao nguon xoay chieu * TimnniV BlSn I dien the k h o n g doi c6 gia t r i Ug t h i cong suat tieu t h y tren R la ^ A P B.2P C.PV2 ^ Huang dan Nguon xoay chieu • P = I R = R D.4P _ 'i,; ; 2R 69 B d t r a kle'n thurc Vît If LTDlt t r e n kenh VTV2 t^p - Chu VSn Cty Bicn J ,2 DVVHKhang VIft m o t n g u o n d i e n tong h o p c6 bieu thirc u = [100cos(100Trt + 7r/4) + 100] V =*P' = 2P =>ChonB T i n h cong suat toa nhiet tren dien t r o Chu y: A SOW B 0 W mach noi tiep chi'm tu thi chi ddng dien xoay diicii di qua: I^^ = , ^ mach not tiep khong chi'ra tu thi cd dong dien xoay chieu va dong mot chieu deu di ^ 1,^,= — Do do, dong liicu dun Chon D V i du 7: Dat m o t d i e n ap c6 bieu thiVt u = 200N/2 cos2(1007rt) (V) vao hai dau d o a n mach AB g o m d i e n t r o R = lOOQ va cuon cam t h u a n c6 d o t y cam T r o n g toan hoc de cong hai vec to a va b , SGK h i n h hoc, g i o i thieu hai quy tac: quy tac t a m giac va quy tac h i n h b i n h hanh 0,25/7t ( H ) mac n o i tiep Cong suat toa nhiet tren d i e n t r o la , A.280W B SOW C W D SOW Humgdan ^ Ap d u n g cong t h i i c bac vie't l a i : u = lOO-Jl + 100N/2cos2007tt ( V ) Z L = 2007t.L - 50 ( Q ) ; P = I^^R + I^^R = [ R P = 10012 100^100 100 1002+502 R +- U^R = ( W ) r > C h o n A Hinh a 71 Bo trg hicn thiic V^t li LTDII tren kenh VTV2 Cty T/SHff MTV DVt^H KHang t$p 2- Chu VSn Bl€n Vlft a) Quy tac tarn gidc N o i d u n g cua q u y tac tarn giac la: Tir d i e m A t u y y ta ve vec t o A B = a, roi t u d i e m B ta ve vec t a B C = b K h i vec t o A C d u o c goi la tong cua hai vec t o a v a b (Xem h i n h a) b) Quy tac hinh binh hanh d'> viôx }>noh A > if!-i n y n > n f - f ( , J >••'•('( , r r p r f N o i d u n g ciia q u y tac h i n h b i n h hanh la: T u d i e m O t u y y ta ve hai vec to o O B = a va O D = b , sau d u n g diem C cho O B C D la h i n h b i n h hanh thi vec t o O C la tong ciia hai vec t o a va b (Xem h i n h b) Ta thay k h i d u n g q u y tac h i n h b i n h hanh cac vec t o deu c6 chung m o t goc O nen goi la cac vec t o b u o c , Goc h o p b o i hai vec t o a va b la goc B O D (nho h o n 180°) V a n d u n g q u y tac h i n h b i n h hanh de cong cac vec t o t r o n g bai toan dien i xoay chieu ta c6 p h u o n g phap vec t o buoc, neu van d u n g q u y tac tarn giac t h i ta c6 p h u o n g phap vec t o t r u g t ("cac vec t o n o i d u o i nhau") 2) C a so vat l i ciia phirong phap gian vec to ' ""^ *Chgn ngang la true dong dien, diem O lam goc *Ve ISii luol cac vec-to" bieu dien cac di^n ap, cung chung goc O theo nguyen tac: ji: ' ik + L - len + C - xuSng + R - ngang Do dai cac vec-to' ti le vol cac gia tri liieu dung tuolig ling *Chi t6ng hffp cac vec-to" dien ap c6 lien quan den du kien cua bai toan ^ -., •Bieu dien cac so Ueu len gian •Dua vao cac he tliijc lutmg tam giac de tim cac dien ap hoac goc chuabiet Mot so'diem can heu y: ; ,5> , • Cac dien ap tren cac phan tu* d u g c bieu dien b o i cac vec to ma chieu dai t i le v o i dien ap hieu d u n g ciia no D o lech pha g i i i a cac dien ap la goc h o p boi gii>a cac vec t o t u o n g l i n g bieu Xet mach d i e n D a t vao d a u doan A B m o t dien ap xoay chieu Tai m o t thoi d i i n chiing D o lech pha gii>a dien ap va c u o n g d o n g dien la goc h o p boi ^ d i e m bat k i , c u o n g d o d o n g dien m o i cho tren mach dien la n h u vec t o bieu dien no v o i true I Vec t o " n a m t r e n " ( h u o n g len tren) se nhanh N e u c u o n g d o d o n g dien d o c6 bieu thiic la: i = IQ coswt ( A ) t h i bieu thuc ^^y; dien ap g i i i a hai d i e m A M , M N va N B Ian l u g t lac , ( ^ j u^^l = U L V cosf Q t + - ( V ) UMN , ; i ^.i^.uuA - n pha h o n vec t o " n a m d u o i " ( h u o n g xuong d u o i ) Viec giai cac bai toan la nham xac d j n h Ion cac canh va cac goc ciia cac tam giac hoac t i i giac, nha cac he thiic l u g n g tam giac v u o n g , cac he thuc l u g n g giac, cac d j n h l i ham so sin, ham so cos va cac cong thiic toan hgc • , , M A ' y ] t i f f J ^rit =UKV2coswt(V) " N B = Uc\/2cos ( D t - - (V) + D o do, dien ap hai dau; A , B la: u^g = u + U^N +"NB• + Cac dai l u o n g bien thien dieu hoa ciing tan so' nen c h i i n g c6 the bieu dien b a n g cac vec t o Frexnel: U ^ B = U L + U R + U C (trong do I o n ciia cac vec to bieu t h i dien ap hieu d u n g ciia no) + —•— D e thuc h i e n cong cac vec to tren ta phai van d u n g m o t t r o n g h a i quy tac cong vec to Ve gian vec ta theo phuong phap vec to buoc gom cac hu&c nhu sau: a'- • • T •:.d 3) V e gian vec to bang each van dung quy tac h i n h binh h a n h - Phuong phap vec to bupc (vec to chung goc) — • T r o n g toan hgc m o t tam giac se giai dugc neu biet t r u o c (hai canh m o t goc hoac hai goc m o t canh hoac ba canh) so yeu to' (ba goc t r o n g va ba canh) 73 Cty Bo trg kien t h ^ c Viit l i L mil l i c n henh VTV2 t^p - Chu T/VHH nrv T i m tren g i a n d o vecto tam giac biet triioc ba y e u to (hai c a n h mot goc, Khang Vipt hai goc mot c a n h ) , sau dcS giai tam giac de tim cac y e u to c h u a biet, c u tiep u, tuc n h u v a y c h o cac tam giac lai D o dai c a n h c u a tam giac tren g i a n bieu thi d i e n ap h i e u d u n g , d o Ion 400,/ /•I / goc bieu thj d o lech p h a M o t so he thii'c l u o n g tam giac v u o n g : i a' -~ b' + c 1 h- DVVn VSn B i e n b- • H O , o I 306'^ I 11, Chii y: Khi sit dung gian vec ta ta tinli duyc dien ap hieu dung va lech pha T c- u, />- = a.b' R Tie CO th(;'tinh dwgc dong dien, cong sud't: P = l-'R M o t so he thi'rc h r o n g t a m giac t h u o n g : V i d u 2: Tren doan mach xoay chieu k h o n g phan nhanh c6 b o n d i e m theo d i i n g t h i i t u A , M , N va B G i i i a hai d i e m A va M chi c6 cuon cam thuan, a' = b' + c giOa hai d i e m M va N chi c6 dien tro thuan, giCia d i e m N va B chi c6 tu - 26ccos A a b c ^ sin A sill B sin C Phu'ong phdp vec ta bugc chi hicu qua v6i cac bai todn CO R nhm giua dong thai lien qua den dien dien D i e n ap hieu d u n g giCta hai d i e m A va M la 150 (V) va dien ap hieu d u n g g i u a hai d i e m N va B la 200/3 (V) D i e n ap tiVc t h a i tren d o ^ n A N va tren doan M B lech pha 90" D i e n ap hieu d u n g tren R la ' R C dpbatclieo O ^ N ' ^ M B V i d u : Tren doan mach xoay chieu k h o n g phan nhanh c6 bon d i e m theo d u n g t h u t u A , M , N va B Giua hai d i e m A va M chi c6 cuon cam thuan, giua hai d i e m M va N chi c6 dien tro thuan, giOa hai d i e m N va B chi c6 tu A lOO(V) ' 200 L D 180 (V) He thiic ktcing : - =h = be b" R -KJ ,B 300.400 h r 150 / be 'b^+c^ 7300^+400^ 74 A/f UR + U , , U^n = OR + U c = ( V ) = > C h o n A i 150 = 0 ( V ) = > C h o n A UT V i lien quan den U ^ N -L ^ M B " ^ n ta tong h g p theo q u y tac h i n h b i n h hanh = • HethiJtcIildng:h^ =b'.c' Huong dan cac vec ta dien ap do: * cac vec t o dien ap do: U ^ N = UR + U| , 0^415 = OR + U c doan M B lech pha 90° D i e n ap h i ^ u d u n g tren R la C 500 (V) ' D 180(V) V i lien quan den 0^^^ U^û nen ta tong hap theo q u y tac h i n h b i n h hanh d u n g hai d i e m M va B la 300 (V) D i e n ap tuc t h o i tren doan A N va tren B 120(V) C.90(V) Huong dan dien Dien ap hieu d u n g giua hai d i e m A va N la 400 (V) va dien ap h i f u A.240(V) B 120(V) O Uc o 150' ? \ 0 / , 200/3 ! I \ \ A 1 = a J b ' 75 B6 lis> hicn lliiic yjt li LIOll litin Chu y: Neii cho bict « ^ coC tanip,^, VTV2 t^p — Chu V^n Bien cty Timn MTV p vvn m^ng vi^t = L/C tht sm/ ra: R = , , L — = Z,Zc » hcitli ^ R tancpRc = -1 « = - l R 0^, • - • ; _L Y i d v 5: T r e n d o a n m a c h x o a y c h i e u k h o n g p h a n n h a n h c b o n d i e m t h e o Vi c d u n g t h u t u A , B, C v a D G i u a h a i d i e m A v a B c h i co t u d i e n , g i u a h a i d d i e m B v a C c h i c d i e n t r o t h u a n , giCra d i e m C v a D c h i c c u o n t :•./ t h u a n c a m D i e n a p h i e u d u n g g i i r a h a i d i e m A v a D l a 100 0^^ V i d u 3: M a c h d i e n x o a y c h i e u n o i t i e p A B t h e o d u n g t h u t u g o m c u o n Cam t h u a n L, d i e n t r o t h u a n R va URC = 0,75UKL v a A 0,8 tu dien C Cho biet dien ap hieu dung R- = — = ZLZC hieu d u n g chay qua m a c h la (A) D i e n ap tire t h o i tren d o a n A C va tren ctoan B D l e c h p h a n h a u " n h u n g g i a t r i h i e u d u n g t h i b a n g n h a u D u n g A.40Q B.lOOa dan •' C.^>/3:Q, Huong, , i j i V H '-ntiCi j r ' i s h '^^ncvv s i n a = 0,6 '' • ac d e u n e n R \}Q = 0,75a sin a = 0,45a => COS (p = — ,r[ & u i O , S fr/ lA ,,M ''''' : 0,864 = > C h o n B t u d i e n C Cho biet dien ap hieu dung = L/C T i n h h e s o ' c o n g s u a t c i i a d o a n m a c h A B A V2/7 C 43J7 B ^/3/5 Huong = C ,2 = Z,Zc =>UR D I • = 0 ( Q ) !> C h o n B d i e m M v a B l a 40 ^/3 ^ doan AN va tren doan MB lech pha n h a u 90", d i e n a p t u c tren pha u,, = J-r^ChonC phwcmg phdp vec to huge thi khong + ( U L - U c )^• tan cp = U]3 - m"-^ theo (V) NB va hieu C N M UT 1,0, o — ^ AN lech 30" R va dung > ,Zc = t r o t h u a n R va UKL = V3 URC v a UB o V ==l O100,0( (VV)) U V i d u 4: M a c h d i e n x o a y c h i e u n o i t i e p A B t h e o d u n g t h u t u g o m c u o n c a m L, d i e n '"-^ D u a v a o g i a n d o vec t o t i n h d u o c : M+i^L-^cf thuan * •D UK = U = 100N/3(V) U L = a c o s a = 0,8a cos = • 4i = U,- = ^ C T i r d o s u y m a c h c o n g h u o n g : Uf, = 0,75a c o s a = 0,6a U,, u, B -^H IJ cos a = 0,8 D 20 Q dan: T a r n g i a c c a n co m o t g o c 60° la t a r n U R = ULU(_ => A v u o n g t a i t a n a = 0,75: (V) va c u o n g k h a n g c i i a t u d i e n la = L/C T i n h h e so c o n g sua't c i i a d o a n m a c h A B D 0,867 B 0,864 C 0,5 Huong cam • • nen ve vec ta tongl Chi UR, UL, UC roi dp dung ; cos cp = HJL , U nen he Dien tro thuan cua \ Ail c u o n d a y la A Q B l O Q C Q D 20Q \ \ Un \ 77 B S trgkiSn thiic V$t IILTOH ttenkSnh VTV2 l./)> Huong ih van Cty Blen dan i du 8: Tren AOUKUMM : UK = 40>/3.sin30" = 20V3 ( V ) v ; ( :y; ) Ji uf j>iit, ' ' • I I I ' ; , v , : r ;

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