T " ^— A^T" CHU VAN BIEN Gi^o vien chuong trinh bo tro Itien thurc V$t li 12, kenh yffZ - Dai Truy^n hinh Viet Nam Bo tra hion IMi « i i LUYEN m DAI HOC IKEN KENHWi PHAN LOAI VA fHUONG PHAP GlAl CAC BAI TOAN CO BAN, DIEN HINH, HAY, LA VA KHO. Phan i!: Dltn HOW CHIEU • Danh cho ttn sinh lOp 12 On tap va thi Bai hqc, Cao dang. V' Blen scan theo nOl dung va cau tnic 6& tN ciia BO GD E DT, , HA HOI NHA XUAT BAN DAI HOC QUOC GIA HA NQI Cty TNHH mv C h u ae . C h u d e 1. B A I T O A N L I E N Q U A N D E N THCJl G I A N 1) Q u a n he gia tri hieu dung 12 B A I T O A N L I E N Q U A N D E N D I E N LLfONG 19 BAI T O A N LIEN Q U A N DEN M A C H RLCNOI TIEP 23 BAI TOAN LIEN QUAN DEN BIEU 37 D I E N PHLfC DIEN VA DIEU KIEN LECH PHA 47 B A I T O A N L I E N Q U A N D E N C O N G S U A T vA H ESO CONG SUAT BAI TOAN LIEN QUAN DEN GIAN D OVECTO DOI CAU TRUC M a c h chi c6 R t h i u va i cung pha va R = ^ = • ••' ''^v^ 'f v 104 132 II; ' • • • ~ " i ' , = (oL = M a c h chi c6 L t h i u som h a n i la M a c h chi c6 C thi u tre h o n i la — va Z^- = Uo lo Uo (oC lo D o i v o i mach chi c6 L , C thi u v i i o n g pha v d i i nen In / u A2 U„ V i du : D a t vao hai dau m o t cuon cam thuan L mot dien ap xoay chieu c6 gia hieu d u n g qua L la 2,4 A . De c u o n g d o hieu d u n g qua L bang 3,6 A t h i tan so CLia d o n g dien phai bang A . 75 H z . . U U Chude2. 1= MAY DIEN BAI TOAN LIEN QUAN DEN M A Y PHAT DIEN XOAY CHIEU t r i hieu d u n g U k h o n g doi va tan so f thay d o i . K h i f = 60 H z t h i c u o n g MACH, B A I T O A N L I E N Q U A N D E N ClJC T R I 1: • 58 71 H O P K I N , G l A T R I TL/C THCfl :: DI^N Phuong phdp giai B A I T O A N L I E N Q U A N D E N M A C H C H I C O R, C H I C O L , C H I C O C BAI TOAN LIEN QUAN DEN THAY Vipt BAI TOAN LIEN QUAN DEN MACH CHI C6 R, CHJ C6 L, CHJ C6 C MACH DIEN B A I T O A N L I E N Q U A N D E N C O N G HUCJNG MACH DWH Khang _ B. 40Hz. C. 25 H z . D. V H z . I , =• I. = P H A 200 MI- v ' Ir ^""^'^ ^ f2 = f, .1L = . ^ = 40 ( H z ) => C h o n B. U I2 3,6 "If'a'l 0'.' IV^ 27:f7L B A I T O A N L I E N Q U A N D E N M A Y PHAT D I E N X O A Y C H I E U PHA . 211 BAI TOAN LIEN QUAN DEN DONG C ODIEN 215 hieu d u n g qua mach la 2A. Neu mac tu vao nguon u = Ucos(1207tt + 0,5::) BAI TOAN LIEN QUAN DEN M A Y BIEN AP 225 (V) thi c u o n g d o hieu d u n g qua mach la bao nhieu? BAI TOAN LIEN QUAN DEN TUYEN 237 A. 1,2N/2A. TAI DIEN B A I T A PD I N H T I N H B A I T A PD I N H L U O N G V i du : M o t tu dien k h i mac vao nguon u = uV2 , 286 ' C. V2 ""'XHuongdan 253 ^,„rn:.-.:v;.r.r::.::;:::.T;::::.:^^^ , B . 1,2A. cos(100Kt + 7t) (V) thi cuong A. D . 3,5 A . ••*'-,''-:''>:^'/2 (V) t h i d o n g dien CO gia t r i tuc t h o i %/6 (A). H a y tinh tan so cua d o n g dien. A. B. ( H z ) . 120 (Hz). ' ' • 360.6 44=:> Z L = 2nfL = 360.2 ' C. 100 (Hz). Huang =1 , — +— ^ =1 dan In I dan 4+4=1 fUo=200 10000 i.4=i = Wf^ """lo =2=>I = V ( A ) = 120V2 Io-2^/2 = 60 ^ f = lOO(Hz) => Chon C. t K h i tan so tang gap d o i neu la tu t h i d u n g khang g i a m Ian nen d o n g hieu d u n g tang Ian, tuc la F = = V A . N h u n g theo bai F = 0,5 V A = 1/2 nen X = L cho: Z , =2niL 50 =- imi i'" Uo _ 200 ^0 7t L = i(H)=>ChonB. V i d u 5: (DH-2010) Dat di§n ap u = Uocoscot vao hai dau cuon cam thuan c6 t u cam L t h i c u a n g d o n g dien qua cuon cam la Uo U U, D . 60 ( H z ) . (I C rJl_ -^nnan 30000 •2 • on ' '" B. cuon cam t h u a n c6 t u cam I/TT (H) > B.IOOV. V, t h a i d i e m t2 t h i : n A . i = HLcos a)t + — coL C . i = - ^ cos coL B. i = 2. (ot-- n D. i = Huang dan V i mach chi c6 L t h i i tre pha h o n u la n/2 nen (OLN/2 cos 7t a)t + — 2. 7t cos c o t - COL V 2J. Bo trfi kien thijrc V,jt li I. roil = —^cos cot iren kcnh VTV2. t^p - Chu V^n coL-cos Blen Chu y: Mach ^om L ndi tiep voi C thi dien dp giim hai dau doqn mach u = ui, + uc •Chon C. Vi du 6: Dat dien ap u = Uocos(1207Tt - TT/4) (V) vao hai dau mgt tu dien thi von kenhiet (c6 dien tro rat Ion) mac song song voi tu dien chi 120^/2 (V), ampe kenhiet (c6 dien tro bang 0) mac noi tiep voi tu dien chi ( A ) . Chon ket luan diing. ,i' A . Dien dung ciia tu dien la l/{7,2n) (mF), pha ban dau ciia dong dien qua tu dien la n/4. J B. Dung khang cua tu dien la 60 Q, pha ban dau ciia dong dien qua tu dien n'; la = 71/2. . v h r nM'. Wvrl D. Dien ap cue dai giira hai dau tu dien la 120 y/l (V), dong dien cue dai qua tu dien la V ( A ) . Huong dan Dien dung tu duoc xac dinh tir =— = ^ " ^ coC I A 1207rC I20V2 2V2 =i.C= V i du 8: Mot doan mach mSc noi tiep gom: tu dien eo dung khang Z c va cuon cam thuan c6 cam khang Z i , = 0,5Zc. Dien ap giira hai dau tu: uc = 100eos(1007it + 7t/6) V. Dien ap giiia hai dau doan mach la: A . u = 200eos(1007it - 57t/6) V. • •' B. u = 200cos(100Txt - 7r/3) V. C . u = 100eos(1007it-571/6) V. D. u = 50cos(1007it + 7:/6) V. Huong dan , 1+: • |«~.- = thi du'a vao he thi'fc \ V i du 7: Do thj bieu dien cuong tuc thoi cua dong dien xoay chieu chi c6 cuon cam thuan c6 cam khang ZL = 50 Q o hinh ve ben. Viet bieu thue dien ap tuc thoi giira hai dau cuon cam. ' " hi,;: i ( A ) A . u = 60cos(507it/3 + 7t/3) ( A ) . B. u = 60sin(1007rt/3 + n/3) ( A ) , C. u = 60eos(507it/3 + n/6) ( A ) . D. u = 30cos(507rt/3 + Tt/3) ( A ) . hoac Uo=IoZc Mach chi c6 C thi i sdm pha hcfn u Id K/2. Mach chi c6 L thi i tre pha hcfn u Id n/2. ••1 2) Neil cho ii;i2 ui;u2 thi dim vao he thuc /.I 44Uo=? T2 TT2 (I J__Uo Mack chi c6 C thi i sdm pha hcfn u la TZ 12 vd ZQ = coC Mach chi coLthii tri pha hem uldn/2vdZi=(dL Huong dan 5071 • \% -n,.:,, T • \ Vi mach chi eo L thi u som pha han i la 7t/2 nen 507rt 71 71 • CO = ?. In 150 V thi cuong dong dien mach la A . Bieu thuc ciia cuong 27t i = — den i = Old — = = 0,01 12 12co , co = ?. dien CO dien dung 0,2/7t (mF). thoi diem dien ap giua hai dau tu dien la = — ycidang.dive i = 0nernp = — 2. Thdi gian ngdn nhdt ditii = IQ V i du 9: (DH-2009) Dat dien ap u = Uocos(1007rt - 7t/3) (V) vao hai dau mot tu i = IQ cos (cot + cp) = 1,2 cos (cot + cp)(A) Liicdau,i • Z L + u^ Thay U Q ^ I Q Z L = 1- (F) Vi mach chi c6 C thi i som pha hon u la n/2 nen 1207rt-^ + ^ 120Trt + • Chon A . i = I>/2cos 1207tt-4 + -2 =4cos :fUSU.:dt' Up u = -0,5uc + U c = 0,5uc = 50 cos 1007Ct + - (V)=>ChonD. j j i ,:v 6, Chu y: (dm) in:t)\i ^n;.iC) .!'-/2 cos(1007rt + 7r/6) ( A ) . B. i = 5cos(1007rt + 7t/6) ( A ) . C. i = 5cos(1007tt - 7r/6) ( A ) . D. i = V2 cos(1007rt - 7t/6) ( A ) . h/.'AM.ii'^y'AH Cdch 1: Gidi tuan tu: 1 Huongdan );|^:Kr;i;flj!p*iJ,r.):^i;^»;.fi!a iriJ'rrs! hamh. it'jil: ••.!,!'• : :: ,. Bo trfl kicn Ihitc V^t li LTDH tren hcnii VTV2, \ / => C O S l O O T l t - u = I Q Z C COS l O O T l t - - 3/ \ = u + sin l O O T T t V 2J -1 [1,50 Cdch 2: Gidi nhanh (van J Cty Bicn 3. IQZC u = I Q Z , ^ cos -i 3y u, ^5.10 + ^2 150 Thny U() = l o Z c -4 .I„=5(A) In .50 chieu. Biet dien ap c6 gia t r i tiic t h o i 60^6 lOOKt-- = -+k.27T lOOTit-- = = 600V2cos[ l O O T i t - - | ( V ) . V j + 1.271 (V) t h i d o n g dien c6 gia t r i tuc t h o i -^6 ( A ) . Ban dau d o n g dien tuc thoi bang gia t r i cue dai, bieu thii'c C L i a d o n g dien la + A ( s ) ( k = 0/1,2 ) 240 50 t = -- (V) t h i d o n g dien c6 gia t r i tuc 1200 3) Ta thay: ^/2 6, t h o i yfl (A) va k h i dien ap c6 gia t r i tuc t h a i SOs/l 2014 + — ( s ) ( l = 1,2,3 ) 50 = 1006 d u => t = 1006T + , . De t i n h t2 ta c6 the d u n g v o n g tron l u g n g giac: A. i = 2^y3cos(^007tt + 7t/2) ( A ) . B. i = V2 coslOOTtt ( A ) . C. i = V c o s i t ( A ) . D . i = ^/3 cos(507it + 7r/2)(A). Huong 360.6 360.2 10071 CO Up coC I„ rad • CO = 50TC 200 (s) t = 1006.0,02 + — = 20,135 (s) 200 ' ^> , , 2K + - (t>, - On , dan Uo=120V2 Vift _3^ = 0 V c o s f l 0 t . . ' ' " ^ - - l = 0 V ( V ) . •I 6y i = 5cos 100Ttt + - ( A ) : ^ C h o n B. V i d u 10: Dat vao hai dau tu dien c6 dien d u n g 1/{3n) (mF) m o t dien ap xoay 2) Giai p h u o n g t r i n h : u = 600 (V) => cos l O O T t t - - = 1- Kliang MTV DVVH => In = A => i = 5cos 1007:t + - V i mcich chi c6 C thi i som pha hem u la TI/2 nen tat): D u a vao he thuc: -4r + Tnnn V i mach chi c6 tu dien nen dien ap tre pha hon d o n g dien la n/l: u ( \ i = IQ cos t^p - Chu Vdn 4) Ta thay: 2014 = 503 du: => t = 503T + t j . De t i n h t2 ta c6 the d u n g v o n g t r o n l u o n g giac: V i ban dau d o n g dien tiic t h o i bang gia trj eye dai, bieu thiic ciia d o n g d i e n CO dang i = I,, cos cot thay so vao ta d u g c i = 2V2 COSSOTTI ( A ) => Clion C. V i d u 11: Dat vao hai ban tu dien c6 dien d u n g 100/(37r) (|aF) m o t dien ap xoay 27t O , - On t , _= ^2 CO lOOTt (s) = > t = 503.0,02 + 120' ' • 120 chieu u = Uiicos(1007it + (pu) (V) t h i d o n g dien qua t u c6 bieu thuc CM i = V cos{1007tt + 7x/3) ( A ) . loan cho dien ap (dong dien) a thai diem tim dong dim 1) T i n h d i e n ap g i i i a hai ban t u tai t h o i d i e m t = (ms). 2) Xac d i n h cac t h a i d i e m de dien ap u = 600 (V). » 3) Xac d j n h t h o i d i e m Ian t h u 2014 de u = -300 V2 (V). 4) Xac d j n h t h o i d i e m ian t h u 2014 de |u| = 300 V2 Huang 1) T i n h d u n g Ichang: Z c = — = 0 ( Q ) . coC dan (V). t• 6041 600 y: Vi v6i mach chi chiia L hoqc C thi u va i vuong pha nen thuang c6 bai (dien dp) a thai diem triivc hoqc sail mot khoang thai gian (vuong pha) A t = (2n + l)T/4: U2 I ',/ V i d\ 12: D a t vao hai dau doan mach chi c6 cuon cam t h u a n c6 d o t u cam 0,4/7t (H) m o t dien ap xoay chieu u = UocoslOOTct (V). N e u tai t h a i d i e m ti dien ap la 60 (V) t h i c u o n g dong dien tai t h o i d i e m ti + 0,035 (s) c6 Ion la A. 1,5 A . B. 1,25 A . C. 1,5 V3 A . D. V2 A. Cty B S tr^ kieti thUc V^t II LTDlt tteti k&nh VTV2. t$p - Chu VSn Bi&n Huong 71 =0,035 = — Cam khang Z, = w L = ( Q ) . V i t2 60 pha nen: 40 dan = l , ( A ) = > C h o n A. V i du 1: Dat dien ap xoay chieu c6 trj hieu d u n g 120 la hai thoi d i e m v u o n g m o t dien ap xoay chieu u = UocoslOOnt (V). N e u tai t h a i d i e m ti dien ap la 50 (V) t h i c u o n g d o n g dien tai thai d i e m ti + 0,005 (s) la: B. , A . C. 1,5 A . Huong z, =• (oC = . . i '(t]+0,005) 1007rt + - 2. COS •(ti+0,005) - D . 0,8 (s). T h o i gian hoat d o n g s: b arccos 12071 U,) 2/;^"^t!::'''';:''^^'^'''^^ 60V2 = 60.4. Bie't den sang k h i dien ap =50 A. 0,5 Ian. 1007i(ti+0,005)- ° 100 7= = —(s) => Lnon 120V2 L. '' dat vao den khong nho h o n 155 V. Ty so giCra filsJ , (|„., ,>|' ,| ^0 ' T h a i gian hoat d o n g t r o n g m o t chu k i : t^ = 41, = 4.—arccos— thai CO gia tri bang 0,5Io vao n h u n g thai diem j. B. 1/400 s v a 2/400 s. dan K h i bai toan chi yeu cau t i m hai thai diem dau c6 the giai p h u a n g trinh sin (cot + cp) = s i n a = Un l u o n g giac: arccosi • D . 1/600 va 5/600 s. I Huang b . T h a i gian hoat dong t s: thj = t.f.4.—arccos— (s) ;' losinlOOTit. T r o n g khoang thai gian tCf den 0,01 ? c u o n g d o n g dien tiic . t ' d i j n g v o n g t r o n l u o n g giac. A. 1/300 s v a 2/300 s -?. C. 1/500 s va 3/500 s. ''''"^ U(, ~ • ,:, De xac d i n h cac thoi diem c6 the d u n g giai p h u o n g t r i n h l u o n g giac hoac Thoi gian hoat dong s: ft^ = f.4.—arccos — v V i du 1: (DH-2007) D o n g dien chay qua m o t doan mach c6 bieu thuc i = b T h a i gian hoat d o n g t r o n g m o t nua chu k i : 2t, = 2. —arccos-—- —T 2T 2) T h a i diem de dong dien hoac dien ap nhan mot gia tri nhat dinh chi hoat d o n g k h i u nam ngoai khoang (-b, b) (xem h i n h ve) CO D . Ian. tt chi hoat d o n g k h i dien ap tuc thai c6 gia t r i k h o n g nho h o n b. Vay thiet bj CO Ian. dan T tT h o i gian den tat m o t chu k i : t, = T - tj^ = — => — = => Chgn B. rfniiiaO, M o t thiet bj d i e n duoc dat d u a i dien ap xoay chieu u = Uocoscot (V). Thiet b i " C. ^ T h o i gian den sang m o t chu k i : . . ^ b T 155 t, = 4.—arccos = 4.—arccosCO 2n 220V2 r' i;*, ' ' * • p , B. Ian. Huang lift: ^- = - , ( A ) =>Chon A . 1) T h a i gian thiet b i hoat dong. ,. • dan khoang thai gian den sang va khoang thoi gian den tat t r o n g m o t chu ky la Phuangphdpgidi HtU „ V tan so'60 H z vao hai V i du 2: Mc)t den o n g su d u n g dien ap xoay chieu c6 gia trj hieu d u n g 220V. BAITOAN LIEN QUAN DEN THOfI GIAN;0 r C.2/3(s). Huong CO dan ;„••• , B. l/3(s). t = f.4. —arccos D.-1,5A. = 0 Q ; u = Uo cosl00Tit=i> U(f^j = U , , coslOOTtti cos Vlft dau m o t bong den h u y n h quang. Bie't den chi sang len k h i dien ap dat vao A. l/2(s). V i du 13: Dat vao hai dau doan mach chi c6 tu dien c6 dien d u n g 0,l/7i (mF) A.-0,5 A. M I V U VVH Khang den k h o n g nho h o n 60 N/2 V. T h o i gian den sang m o i giay la: .-./c',,; r-iT- Train T arcsin^ ' arcsin^ ! '—* arccosS- cos(o)t + cp) = c c « a : j cot + cp = a + (271) o,t + (p = r - a + (27i) ^P^^fk^''^-- cot + (p = a + (2?:) „: ., ojt+ = - a + (27t) (Neu t i m t < m o i cong ? : ) . O b — arccos — b —arccos — i = Iosinl007it = ^ (s) 600 => Chon D. -(s) ^J^'' 1007tt = — = > t = 600 1007rt = - : t = 13 B6 trff kiSn thCrc V^t l i L T B t l trSn kSnh VTV2. t^p - Chu VSn Cty Bien Timti nrv DVVH Khang Vipt V i du 2: D i e n ap hai dau doan mach c6 bieu thiVc u = 200cos(1 OOTit + 57r/6) V i du 4: D i e n ap giua hai dau m o t doan mach ccS bieu thuc u = U()COS(2TTt/T). (u bang v o n , t d o bang giay). T r o n g ii - O =• ^ t= -—(s) Chon A. (Neu k h o n g cong them 2n V r Cac t h a i d i e m ma u = 0,5Uo va dang tang t h i chuyen d o n g t r o n deu nam o 1007rt + — = - - + 27i=>t = — ( s ) 600^ ^ 100 . ] B. 12055.T/6. Huotig dan Cdch 1: Gidi phumig trinh luong gidc Lan ,-\y-'''' D . 1/200 va 7/600 s. Huong dan u = 100=^ cos lOOTTt '• A. 12089.T/6. B. 1/400 s va 2/400 s. \f|s^,,i;,:, C. 1/500 s v a 3/500 s. , i 12083T + 20131 = • ChonU. V i du 5: D i e n ap giua hai dau m o t doan mach c6 bieu thuc u = Uocos(2Tit/T). dong: Ti'nh t u t h o i d i e m t = s, t h i thoi d i e m lan t h u 2010 ma u = 0,5U() va dang + 2Tt nen thoi gian: giam la 71 „ 5T: - - + 271 - - - 0) Lan 10071 A.6031.T/6. 600 V i t r i xuat phat: „ dien ap tuc thoi c6 gia t r i bang 100 V u n g v o l pha dao d o n g : 71 57r Lan 3^^^"T 2 = — + 27T nen thoi gian: t = ^ - O o w 10071 200 V i du 3: D i e n ap giCra hai dau m o t doan mach c6 bieu thuc: u = 120sin]007rt TT Lan 2010 (u bang v o n , t bang giay). H a y xnc d j n h cac thai d i e m ma dien ap A. t = J/3 + k ( m s ) . B. t = l/6 + k ( m s ) . C. t = l/3 + 20k (ms). D. t = 5/3 + 20k (ms). '* Hicangdan . , u = 120sinl007tt = 60 71 . . ' ' hihm^:r>: , i n n . „ => OOTlt = — + k27t u = 1007i.l20cosl007rt>0 , ^ -+k .10' (ms) = - + . k ( m s ) => C h o n D . =>t = +k (s) = 1600 100 J 600 100 C. 12059.T/6. '< dan Huang = ( IOOTT.O) = D . 6025.T/6. '" " ' T ma u = 0,5Uo theo chieu am: t, = — . 2010 ma u = 0,5Uu theo chieu am: T/6 ^'tW)-' =>ChonB. u = 60 V va d a n g tang ( v o i k = 0,1, 2, .). B.12055.T/6. • , , , ,^ V i du 6: Dat vao hai dau doan mach m o t dien ap u = UocoslOOrct (V). T r o n g chu k i t h u cua d o n g dien, cac thoi d i e m dien ap tuc t h o i u c6 gia t r i bang dien ap hieu d u n g la A. 0,0625 s va 0,0675 s. V C.0,0025 s va 0,0075 s. % •I ' ••/ j. ' •"' B. 0,0225 s va a0275 s. D . 0,0425 s va 0,0575 s. Huang dan Cdch 1: Gidi phuang trinh luong gidc. ' ; Bidttff USn thiic V^t It LTDH trSn kenh VTV2. t4p - Chu Van Cty Timii Blgn Chu y: Trong mot chu ki c6 tliai diem de /u / =b< = j = i > t i =0,0025(s) C h u k i t h u 1: u = n md lul •COSl007tt = - = - j + 27r=>t2 = a ] ( s ) Chu k i thu- 2: { It^ = t + T = 0,0375(s) Chu k i t h u 3: :.f 1, ' 'J '-^-> [ t , = t + T = 0,0575 (s) n ti = ^ 7t „ O, = — + 2;: den Id : Lan den u-i Id : Lan den Id : 0) => to = _^ = 0,0225(s) '?r.' :.}:£rifiJ i '' ^^"'^ vd den Id: Lan 4n + den Lan 4n + den la Lan 4n + den la = nT t4„+] t i u ^ i = t i + nT. , , So l a n f neu dU => t = nT + t, nhanh: • = n t = nT + t2 neu d u = > t = nT + t3 => t :2 A, = n T +14 Ta co the ,., [ n e u d U = > t = nT + t2 Huong Ta nhan tha'y: rut 'meo' -'iiu/ ••) f:V dan •' 2013 = 503 d u ^ t2oi3 = 503T + tj. Ta d i i n g v o n g t r o n l u g n g giac de t i n h t i : \' T Idm 24 , „ , ' ^hmr (A) £ , v D. t = 12073/1200 (s). C . t = 2411/240 (s). - gt) B. t = 9649/1200 (s). K:V-M • Do do, chu ki dau tien c6 hai thai diem ti ti; chu ki thu c6 hai tlwi diem = t i + nT +1 dp d o n g d i e n tuc t h a i bang c u a n g d o n g d i e n hi^u d u n g la diem tren true ung vai hai diem tren vdng trdn lugng gidc (trit hai vi tri Men). t2i,vi 4n A . t = 12043/12000 (s). (A) Chii y: Ncu khong han chcboi dieu kien dang tang hoac dang gidm thi ung v&i mot t4 = t i + T; . thai diem lan thie - n/3) (A) (t b a n g giay). T h a i d i e m t h u 2013 gia t r i t u y ? t d o i ciia c u o n g +271-0 IOOTI VJ^ V i du 8: D o n g d i e n xoay chieu qua m o t doan mach co b i e u t h i i c i = Iocos(1007it IOOTI Oj-Og Lan neu dif = 0,0025(s) t5 = t i + T = 0,0425(s) Chu k i thiV 3: ^ ^ => Chon D. tg = t + T = 0,0575 (s) • Lan Kbang loo':. { -0 (0 f.3 = t i + T vd ld:ti. , , Ta CO the rut meo lam nhanh: ' xoay chieu qua m o t doan mach co bieu t h u c i = Iocos(1007rt - n/3) (A) (t bang giay). T h o i diem t h u 2009 c u o n g d o n g dien tuc thai N e u biet gia t r i tuc t h a i t h a i d i e m t i m gia t r j a t h a i d i e m khac ta co i = Io/V2 la A. t = 12049/1440 (s). ; ; , .1 C . t = 24113/1440 (s). Ta tha'y: B. t = 24097/14400 (s). D . t = 22049/1440(8). Huang 2009 3) Cac gia tri tuc thoi cac thoi diem dan = 1004 dU ^ t2oo9 - 1004T + t^, Ta d u n g v o n g tron l u a n g giac de t i n h t i : T the giai p h u a n g t r i n h l u g n g giac hoac d i m g v o n g t r o n l u g n g giac. V i du 1: (DH-2010) Tai t h a i d i e m t, d i e n ap u = 200 ^ cos{1007tt - n/2) (trong u t i n h bang V, t t i n h bang s) co gia t r i 100 V (V) va d a n g g i a m . Sau t h a i A. -100 V. U(t^) =200V2cos > «,':-»U,l/:i.J' T 24097 t2oo9 = 1004T + — = ^ ~ - ( s ) ^ Chon B. Cdch 1: U(,l IK B. 100 V3 (V). Huang t ^ j d i e m 1/300 (s), d i e n ap co gia trj la = -200o)sin OOti ^ — C. -100 ^ (V). 'f j f D . 200 V. ST dan = IOOV2. COti — ^ 7t 7t ^ = — => coti = ^ 5n — cot 17 Cty mHHnTVDVVHlihang B6 trjf kie'n thiic V^t li LTBH tren kcnh VTV2. t^p - Chu VSn Bien ti + = 200V2cos 300 j ' 71 300> 2_ ^ CO t1 + V ^ — = -100^/2(V)=>ChonC. Cdch 2: K h i i = N/2 (A) va dang giam t h i pha dao d o n g c6 the chon: O j = —, Cdchl: K h i u = 100 V2 (V) va dang giam t h i pha dao d o n g c6 the chon: =- . Sau t h a i d i e m 1/300 (s) (tuang u n g v a i goc quet Acj) = (oAt = 1007t/300 = 7t/3) t h i pha dao d o n g : O2 = + AO = — f =>U2 =200V2cosO2 =-100>/2(V)=>ChonC. thoi d i e m gan nhat de i = ^/6 (A) t h i pha dao d o n g O2 = - — + 2T[ . 0' D o do, t h o i gian: t i = — B. 271/3. ' • A . (A) hoac - ( A ) . B. - V2 (A) hoac ( A ) . C. ->/3 (A) hoac (A). D . Vs (A) hoac - ( A ) . dan V i k h o n g Hen q u a n den chieu dang tang hoac dang g i a m nen ta c6 the giai p h u o n g t r i n h l u g n g giac de t i m nhanh ket qua. i = 4cosl207i t i +• 240 1207iti = ± ^ 2J 2. = ±2(A) i = V2 cos(1007it + (p) (A), t t i n h bang giay (s). Vao m o t t h a i d i e m nao do, B. 5/600 (s). Huang Cdchl: t = C. 2/300 (s). dan •'^•i^f>fi-" T. T T 3T (s)=^Chon A. + — + — + — =: = 12 4 200 T __l—^ -A \2 = IQ cos (cot + 0,5A 0,5AV3 ^/3Io =>(cot + cp2) = - 92) = - ' D u a vao v o n g l u g n g giac, hai d o n g dien xoay chieu c6 cung t r i tuc thai 0,5 ^/3 lo, d o n g d i e n dang g i a m iVng v o l niia tren d o n g dien dang tang l i n g v o i nua d u o i . H a i d o n g dien lech pha la Acp = — •, ' . .3 d a n g g i a m t h i sau it nhat la bao lau t h i i = + V6 A? A . 3/200 (s). LA1 i ' l = - W I Q sin(cot + (pi) > Cdchl: V i d\ 3: D o n g dien xoay chieu chay qua m g t doan m a c h c6 bieu thiic 1= sfl Ava i,=IoCos(cot.cpO = - ^ ^ ^ ^ ^ ^ ^ ^ ^ _ . ^ Acp = - => Chon A. COS 1207rti + - = COS V,;, i '2 = -COIQ sin (cot + (p2 ) < C u a n g d o n g d i e n a t h o i d i e m t = ti + 1/240 (s): dan :"'=,'"v;:r Cdchl: Z D.7C/2. C. 7t. Huong Tai t h o i d i e m ti nao do, d o n g dien c6 c u a n g = 4cosl207tti = 2V3 • =— ^ = (s) => Chon A ' ' 0) lOOTt 200^ V i du 4: Vao cung mot thoi diem nao hai dong dien xoay chieu h = Iocos(cot + cpi A . 7t/3. bieu thiic i = 4cos(1207it) (A), t bang giay. Huong - ^ + 2TC-~ A q tang m o t d o n g dien dang giam. H a i d o n g dien lech pha n h a u V i du 2: D o n g d i e n chay qua m o t doan mach c6 c u a n g d o n g dien bang J- - va i2= Incos(cot + 92) CO ciing trj tuc thai 0,5^/3 lo, n h u n g m o t d o n g dien dang ,,, . 2V3 A . D e h t h a i d i e m t = ti + 1/240 (s), Vl^, B A I T O A N L I E N QUAN DEN D l | N D . 1/100 (s). Chon A . LlT^NG Phuong phdp giai 1) Dien lugng chuyen qua tiet dien thang day dan Theo d i n h nghia: i = ^ dt dq = i d t . D i e n l u g n g chuyen qua tiet dien thang ciia day dan t i n h t u t h a i d i e m ti den Ctyrmin 30" va cuang hieu dung mnch la N/3 (A). Dien t.6 thuan cua cuon day la A. 40 Q. B. 10 Q. ''" • C. 50 Q. Huong dan A O U K U M B : U K = 40x/3.sin 30" = 20^3 ( V ) ZA.OUK+,.UAN : U K „ . ^tj^ D. 20 Q. |U'R=80(V) fi ' n -CO truong hop bang A. 75 W. B. 160 W. Dap an C C. 90 W. ' D. 180 W. ' ' 307 Bo trp kien thiic V$t IS LTOtl tren henh VTV2. t^p - Chu VSn Bien' "au 47: Doan mach A B no'i tie'p g o m hai doan mach A M va M B . Doan mach Cau 44: Dat m o t n g u o n dien xoay cliieu c6 hieu dien the'hieu d u n g U va tan so A M la m o t cuon day c6 dien t r a thuan R = 40 Vs n va d g t u cam L = 0,4/n f vao hai d a u d o a n mach g o m R, L, C mac noi tie'p, t r o n g d o cuon day If H , doan mach M B la m o t tu dien c6 dien d u n g C thay d o i dugc, C c6 gia t r i t u o n g . N o i hai dau t i i dien v o i ampe ke thi thay no chi l A , d o n g thoi h u u han va khac k h o n g . Dat vao hai dau doan mach A B m o t d i e n ap: d o n g dien tuc t h a i chay qua ampe ke'cham pha m o t goc — so v o i hieu dien UAii = 240cosl00t (V). Dieu c h i n h C de tong dien ap hieu d u n g (UAM + U.MB) dat gia t r i cue dai. T i m gia trj cue dai cua tong so'nay. the tuc t h a i g i i i a hai d a u doan mach. N e u thay ampe k e b a n g m o t von ke A.240V. B.240^/2V. , Huong t h i thay no chi 167,3V d o n g thai hieu dien the tuc thai giiJa hai dau v o n ke c h a m pha m o t goc ^ so v o i hieu dien the tuc t h o i giiJa h a i d a u doan mach. SM" dung Biet rang ampe ke va v o n ke deu l i t u o n g . H i e u d i e n the hi6u d u n g cua 120N/2 _ A M _ M B n g u o n dien xoay chieu la sin 60'.0 A. 100V. V > • B. 125V. < >L, .u . C. 150V. C. 120V. ^ sin a ' , A. . ' i ' , ' . ' , s i n a + sinp => D a p an C ^ ^. sinP AM + MB D . 175V. --1 D . ^ V. i , dan dinh li ham so sin cho A A N B : '= nii-j ,.:> :'• ' -''' .o Cau 45 ( D H 2010): Dat dien ap xoay chieu c6 gia t r i hieu d u n g k h o n g d o i , tan so' 50Hz vao hai d a u doan mach mac no'i tie'p g o m dien t r a t h u a n R, cuon 2sin"tPcos"^P '^,^8"^''^' cam t h u a n c6 t u cam L va t u dien c6 dien d u n g C thay d o ' dugc. Dieu chinh dien d u n g C den gia t r i t = —VLC ——F 471 hoac ——F In t h i cong sua't (UAM+UMB)-240V2COS^ tieu t h u tren d o a n mach deu c6 gia trj bang nhau. Gia trj ciia L bang A. — H . B. - H . C. — H . /li,^, = max-240V2(V) tn' - r : D . - H . => D a p an D C a u 48: D a t m o t n g u o n dien xoay chieu tan so 50 H z vao hai d a u d o a n mach Cau 46: M o t d o a n mach xoay chieu noi tie'p A B g o m d i e n t r o t h u a n R, cuon R L C mac n o i tie'p, t r o n g dien d u n g C bien d o i . K h i tu d i e n c6 dien d u n g cam t h u a n L va t u dien c6 dien d u n g C. D i e n ap giua hai dau doan A B la , Ci = l/(37r) m F t h i c u o n g hieu d u n g cua d o n g dien t r o n g mach c6 gia trj u = Udcoscot (V) t h i dien ap tren L la UL = Uocos((ot + 7i/3) (V). M u o n mach cue d a i . K h i t u d i e n c6 dien d u n g C2 = 3/(257t) m F t h i hieu dien t h e ' h i e u xay cgng h u o n g t h i dien d u n g ciia t u bang A.CV3. d u n g a hni dau tu dien c6 gia t r i cue dai. Dien t r o R c6 gia t r i la C. 0,5C. B. C . D . 2C. A.30Q. , Zi - Z r 7t (PL = — m a (pi - = — =>(p = — => tan (p = —i= ^ = tan — R =>R = (ZL - Z c ) V >0 ,j, , . . 71 , 7t 71 UAB=UL^ZAB=X/R'+(ZL-ZC)' =ZL coC cong hi/dng thi Z'c = 2-^=>c'=o,5c mC :. = coC D.60Q. HumgdUn Z c i = - ^ = 30Q coCj =^2(ZL-ZC) = ZL=^ZL=2ZC Muohxdy • • • ZC2 C.50Q. B.4OQ. 250 /mnxZL=Zci=30Q R'+Z2 Ucmax Zc2 = - 250 R^+30^ "T~ 30 R = 40Q Cau 49: Dat d i e n ap xoay chieu c6 gia trj hieu d u n g U va tan so k h o n g d o i vao =Zi =>Z'c=2Zc , . hai d a u A va B cua doan mach mac noi tie'p theo t h u t u g o m bie'n t r o R, . • . , cuon cam t h u a n c6 t u cam L va t u dien c6 dien d u n g C thay d o i . Cac gia trj R, L, C hfru han va khac k h o n g . V o i L = L i t h i dien ap hieu d u n g giira hai d a u bien tro R c6 gia t r i k h o n g doi va khac k h o n g k h i thay d o i gia trj R cua 309 j bien tra. V a i L = L i thi dien ap hieu dung tren doan mach chi chiia R C bang 100 V. G i a trj U bang A.200V. ' \. I O O V V . D.20GV2V. ClOOV. Hu&ngddn U R = IR = R U I cuon cam t h u a n v o i d p t u cam 1/n H va tu dien c6 dien d u n g 0,l/7t m F . D i e n l i n g la •gR=>ZLi =Z, A . 59,6 V va 33,3 V . . C. 50 V v a 100/3 V . L = 2LI:^ZL2=2ZLI=2ZC = U den 2007t rad/s vao hai dau doan mach n o i tiep g o m d i e n t r o R = 300 Q, ap hieu d u n g giira hai dau cuon cam c6 gia t r i Ion nhat va n h o nhat t u o n g R2+(ZL-Zcr ^ U R C = I Z R C Cau : Dat d i e n ap xoay chieu u = 100 ^y2 coscot V v a i 00 thay d o i l u IOOTI rad/s R^2 + Z^ V R ' + ( Z L - Z C ) ' =u " R^ = U = lOOV V R ' + ( Z C - Z C ) ' ' 300^ 1/71 VIO~VTC Cau : M o t doan mach A B g o m doan A M va M B mac n o i tiep. D o a n A M g o m ^ tren A M va tren M B l u o n h i o n lech pha TC/2. K h i mach cong h u o n g thi khong ton tai. (0 : = 0 = ^ U L = dien ap tren A M c6 gia t r i hieu d u n g U i va tre pha so v o i d i ^ n ap tren AB ai. va 50 V . UcoL A B m o t dien ap xoay chieu chi c6 tan so thay d o i d u g c t h i dien ap tuc thai ap tuc thai tren A M lai tre pha hon dien ap tren A B m o t goc V2 V lOO.lCO 100 ^300^ + ( 0 - 0 f "3 100.200 80VS ^300^+(200-50)^ CO = IOOTI = > U L = dien tro R n o i tiep v o i t u d i e n C, doan M B chi c6 cuon cam L. Dat vao i m o t goc a i . D i e u chinh tan so de dien ap hieu d u n g tren A M la U2 t h i dien B.lOOVvaSOV. > D . 50 Huang dan :33,3V » 59,6 V Cau 52: D a t dien ap xoay chieu u = Uocoscot (Uo k h o n g d o i va co thay d o i dugc) vao hai dau doan mach g o m dien t r a thuan R, cuon cam t h u a n c6 d o t u cam Biet a i + a2 = n/2 va U2 = 0,75Ui. T i n h he so cong suat cua mach A M k h i xay L va tu d i e n c6 dien d u n g C mac noi tiep, v o i CR^ < 2L. K h i co = 90 rad/s cong h u o n g . hoac CO = 120 rad/s t h i dien ap hieu d u n g g i i i a hai d a u cuon cam co cung A . 0,6. B.0,8. C.l. D.0,75. Huong dan m o t gia t . j . D i e n ap hieu d u n g giCra hai dau cuon cam dat cue d a i k h i A . 105 rad/s. ' B. 72 V2 rad/s. Huong U, COStti ^ =—- U U2 . costto = — ^ = S i n a i ^ U ^ + ^u J = 1- U2=0,75U] - . i l l = 0,8 u co, COo C0|C02 V2 C. 150 rad/s. D . 75 V2 rad/s. dan = 72 V271 (rad/s) ^/cof+cof ^2 J Cau 53: Dat dien ap xoay chieu u = UocoslOOTit (V) vao hai dau doan mach mac ncVi tiep g o m dien t r o thuan R, tu dien co dien d u n g 0,4/7r (mF) v'a cuon cam t h u a n CO cam k h a n g Z i . thay d o i . Dieu chinh Z L Ian l u g t bang 15Q, 20Q, 29Q va 50 Q t h i c u o n g dc) hieu d u n g qua mach Ian l u g t bang I i , I2,13 va I4. T r o n g so'cac c u o n g d o hieu d u n g tren gia t r j Icrn nhat la C. h. B. I2. A. I i . Huang Zr=- coC * D. k dan = 25(Q) Vi t r i dinh ZLO = Zc =25(Q) Gang g a n d i n h I cang I d n = > Z L va Z L g^n h d n Z L O = 25Q hcfn n e n chi can so s a n h I2 va I3. Zu, = ^ ' ' ^ :=> 25 ^ ^ Z'L2 = > Z L ^ I2 < I3 311 Cau 54: Cho m o t donn mach xoay chieu g o m dien t r o thuan R thay d o i duoc, Mach cgng hudng => Z L = cupn day thuan cam L va tii d i e n C theo thiV t u mac noi tiep v o i nhau. Dat vao hai dau donn mach mot liK/n ap xoay chieu co gia trj hieu d u n g 0 V va tan so f thay doi dugc. K h i f = H z t h i c u o n g d o d o n g d i c n hieu d i u i g Uc =100(V) = Ui. = R thay d o i . Dien d u n g nho nha't cua tu dien la A . 25/TC(HF). .V , B . 50/Tt (HF). C . 0,1/7r (|.iF). D . 0,2/:: (nF). Huong dan U R L = I.ZK,., = U I c^zf R^ + zf . ""'^ = — = lOOQ ^ V =>C> ? ^ hai dau mach dien mgt dien ap xoay chieu co gia t r i hieu d u n g 0 V va co tan so thay ctoi dugc. Gia tri cue dai cua dien ap hieu d u n g tren cugn cam la A.300(V). V „ • ,J .r R^ Z\ n y J thuan cam c6 d o tir cam H , tu d i c n c6 dien d u n g 10'' (F). Dat vao hai dau m a c h dien dien ap xoay chieu chi co tan so goc o) thay d o i . K h i dien ap hieu d u n g hai dau tu C dat gia tri cue dai t h i co co gia trj la B. 707 (rad/s). ,^ C. 2,5.10"^(rad/s). D . 500 (ra'd/s). Huong dan -„ C , B. 0 ( V ) . (l000^/2f VlO-^' I ^ = 1000(Q) ^ ' U c max Z L = Z , =>(oL = 1000 =>(o = 500 (rad / s) C. 0 ( V ) . Huong dan '12,5.10-"^ 10 100' ,-6 u C max D. ( V ) . J- vj.v. = 100Q Hi rnfi;j ngtjo ,/J 12,5.10,-3 L C a u 55: C h o doan mach k h o n g phan nhanh dien t r o 1000V2t), cugn day A . 400 (rad/s). ,73 ii day thuan cam co t u cam , m H va t u dien co dien d u n g pF. Dat vao . gR Z[ < lOOQ => Z c = Z L < 200Q = ^.10-^F lOOn.200 >R = 0 ( Q ) Cau : M g t doan mach khong phan nhanh g o m : dien t r o thuan 0 iX cugn = ( Z , - Z c ) ^ =>Zc = Z L Z = sJR^+Zl U ' - U ? , + ( U L - U C ) ' v . ' A. R U K =100V3(V) 73 +Mdc von ke : t r o n g mach la A va dien ap hieu d u n g giCra hai dau R L k h o n g thay d o i = L-6 = u , _ = u . ^ = u C • = 200.- 10 R Z \, " 100.100 •J - = 250(V) iA\) Cau 58: Cho doan mach M N theo thi'r t u gom dien tro R mac noi tiep v thuan cam L ncYi tiep vcVi tu dien co dien d u n g C thay d o i dugc. la diem noi L v o i C. Dat vao dau doan mach dien ap xoa i UMN = 100 V2 cos(1007it + (p) V. Thay d o i C de dien ap hieu d u n g tren doan 0' thay d o i C de dien ap hiei-i d u n g tren t u cue dai t h i lap bieu thuc dien ap p,\l,a :?.S • A M cue dai thi bieu thuc dien ap tren d o la UMA = 0 ^ c o s l 0 i t V . N e u tren doan M A la Cau 56: M o t doan mach xoay chieu noi tiep A B g o m dien t r o thuan R, cugn A . UMA = 100V6cos(1007it + 7T/6) V. B. UMA = 200 76 cos(1007:t + 7r/6) V . cam thuan L va t u dien C. K h i noi hai cue cua tu dien v o i m g t ampe ke'co C. UMA = 10076 cos(1007rt + 7t/3) V. D . UMA = 200 76 cos(1007:t + 7t/3) V. ' dien t r o ra't nho thi so chi ciia no la 0,5 A va d o n g dicn qua ampe ke tre pha Hwwi^ dan so vcVi dien ap giua hai dau doan A B la 7i/6. Ne'u thay ampe ke bang von ke = IZviA = + = ^ « Cong hUdng , f I J,.,j.„ ,, T nmQ mAh U U | . L iMA s d m p h a h d n u M N la-- vS 313 " M A = 0 C O S lOOTCt .V. • ; A + - (V) (R + r) C O S ( p i = C S ( P • 2) l(R+rr + ^ 200 / 0,. cojC L=CR L-^^ =>LC = Or A' '-—^ (R + r)^ \ M C02L - 0J2C =R ^-^•Wfi^ * C02 (R + r) • cos (pj = • n (R4-r)2 + cojC C0|L = R 100 (R + r) R./'^i -R^2 CO2 Y ™i ( 1—- "1- = 0,96 \ CO2 \ •'•)'r''Xifiyi'iV. lV«2 Cau 61: Cho mach dien noi tiep gom cupn day thuan cam co tu cam L ! thay doi dugc, tu dien C va dien tro R. Dien ap dat vao hai dau doan mach N u = 100 V6 .coslOOnt (V). Khi dien ap hieu dung tren cuon day dat gia trj cue Cau 59: Dat dien ap xoay chieu vao hai dau doan mach noi tiep pom dien tio dai ULMnx thi dien ap hieu dung tren doan mach chua RC la 100 (V). Gia trj R, cuon cam thuan L va tu dien c6 dien dung C thay doi dirge. Khi C thay ULM.IX la doi thi dien ap hieu dung cue dai tren R, L va C Ian lugt la x, y va z. Ne'u A. 100 (V). B. 150 (V). z/y= V'S thi z/x bang i C . 300 (V). D. 200 (V). ] B. 0,75 V2 . ,,; A. 0,5 N/5 . yy.) ryAii; ' m.^imii C. 0,75. Huong dan u , ( U R m a x va U L ^ , , cong huang I ^ , , = - ' :, , _ w D. >/2 . > .^i , { Huong dan 'y U Cmax iy-iiQ / l > ioifrJ |UJ-URC u, => ; U L = 7100^+3.100^ = 200( V ) Z = U I R U, z = R = , V U ^ - = 0,5N/5 Cau 62: Cho mach dien xoay chieu RLC vol R la bien tro va cuon day co dien X Cau 60: Dat dien ap u = 125 -Jl coscot (V), co thay doi dugc vao doan mach noi I t r a thuan r = 10 Q. Khi R = 15 Q hoac R = 39 Q cong suat cua toan mach la tiep AMB. Doan mach A M gom dien tro R noi tiep tu dien, doan mach MB I nhu nhau. De cong suat toan mach cue dai thi R bang chiia cuon day c6 dien tra r. Biet dien ap tren doan A M luon vuong pha v6i | A . 27Q. B. 25Q. rad/s thi mach AB co cung he so cong suat va gia trj bang B.0,85. : C.0,91. (R + r ) ^ + ( Z L - Z c ) Huong dan -Zn Zr U A M -L U M B =^ tancpAM t a n ^ M B = -1 => ~ — — = -1 => L = CR^ c-\ > t)K MI D. 36 Q. - => (R^+r) + (R2 + r) = (R,+r)(R2+r) = ( Z L - Z c r .^-^U 2ZL-ZC R^ 314 u2(R + r) D. 0,82. C. 32 Q. j Hwang dan dien ap tren doan MB va r = R. Voi hai gia trj co = lOOn rad/s va co = 56,257T A. 0,96. ft; RQ + r = |ZL - Z C ' i 315 CtyTmiii Pirv t> VVH Khang-yi^T— .(Ro + r f = ( R , + r ) ( R + r ) = ^ R n +10 = ^ ( + 10)(39 + ) = ^ Ro = Q B 1/ ::' f R r, L = R>/5 Ucmax Z r = =R«0,499 — JR2+(ZL-Zcf ' ^_ u,. \ / \" —> M M u' t Cau 63: H a i doan macli n o i tiep R L C khac niiau: mach T va mach 2, cona h u o n g v o i d o n g dien xoay chieu c6 tan s o g c k Ian l u g t la (oo va 2(oi). Biet tu cam ciia mach gap ba t u cam ciia mach 1. N e u mac noi tiep hai doan mach d o v o i m o t mach t h i no se cong h u o n g v o i d o n g di(R = L(coj-ci)2) = 100Q =>y' = . u = > R = 80(P.) VI202 ^ 4j,2 _ » Zco = —^""^-V^ = A. > Z c „ = 75(Q) ^ Zc3 ^ Uc3 ^ Ucnnax (OjL VIft ^ ( Z L - Z c ) ' + r + r = 2lZL-Zc Rrmax = 2Pn 2ZL-ZC R2=ZL-ZC R2 + = 76^ r = 2R2-76 =^R2 =60,8Q Cty TNHHMIV Cau 71: Dat dien ap xoay chiou 220 V - 50 H z vao hai dau doan mach n o i tiep Huang g o m dien tro 50 f2, cuon cam thuan c6 cam khang 100 Q va tu dien c6 d u n g khang Zc thay d o i . Dieu chinh Zc ian i u g t bang 50 Q, 100 Q, 180 Q va 200 Q thi dien ap hieu d u n g tren t u Ian l u g t bang U c i , Ucz, U c i va Uc4. T r o n g so cac dien ap hieu d u n g noi tren gia t i i ion nha't la A. Uci. (,,,:; n B. Uc2. C.Va. P= u2(R Zro = , ,5b::;ipvfi^'>-, , , = " k : ) ^ 0,008R2+Zf Zcl, = ' ' =0,0056 •" ^'«> .A:-; .muh Zc4 = 0 ' ' =0,005 Gang gan di'nh .1,;,' (R + r ) ^ + ( Z L - Z c ) «Ro =?> ( R „ + r ) +r= ZL-ZC = ( R i + r)(R2 + r) R„ + = 7(15 + ) ( + ) ; -f' \ u- Ro = Q "'"'^ 7 ^ = 1,58 x/T4 U C = L J L „ , , , = U . (R . „ + r ) Z \4 =u. 4,5 ^ ~ r^- CI : ^au 73: Cho mach dien xoay chieu RLC v o l R la bien t r o v a cuon day c6 dien t r a t h u a n r = 10 Q. K h i R = 15 Q hoac R = 39 Q cong sua't ciia toan mach la n h u nhau. D e c o n g sua't toan mach cue dai thi R bang 20 B.25Q. C. 32 Q. R = 100V5 = ^ = 2,5Zc2 = , ( Z L - R ) = ^ Z L = R ZL Ur 1800 I /-M II I U^R^ + Z^ Zci " = 10VT4Q L L C . A.27Q. -——^-2,5Zc2 u Cmax J(R + r ) + ( Z L - Z c f i.t.ii^D Zci ' UZc " U c i = IZQ = ^'^' D . 36 Q. U C . . , . = H S . 0 R ^ VR^ 4R' R = 0 = > U = 100^/5(V) u 75: M o t doan mach R-L-C mac noi tiep. Dat vao hai dau doan mach m o t dien ap xoay chieu c6 gia t r i hieu d u n g U , tan so'thay doi duac. Tai tan so 80 H z dien ap hai dau cuon day thuan cam cue dai, tai tan so 50 H z dien ap hai ban tu cue dai. De cong sua't mach cue dai ta can dieu c h i n h tan so' den gia trj A.loVSHz. B.20VTOHZ. C.loViOHz. D.lOHz. 321 B6 tr^hicn thJrc V^t liLTDH tren kenh VTV2. tpp - Cliu V^n Blen Huang L R2 ULmax CO1CO2 = L va tu dien cc) d i i ' n d u n g C mac ncVi tiep, vc'>i CR^ < 2L. K h i (o = coi hoar co = = ^ = C02= 2OVTO t r o R, cuon day cam thuan L = 2/7i H va tii dien c6 dien d u n g C thay doj 2coi t h i dien ap hieu d u n g giua hai ban tu dien co ciang m o t gia tri. K h i CO = 50 rad/s thi dien ap hieu d u n g giua hai ban tu dien dat cue dai. T i n h co:. A . 25 V2 rad/s. B. 10/lO rad/s. doan mach. K h i C = Ci/2,5 thi dien ap hieu d u n g gifia hai tu cue dai. Tinh tan so goc cua d o n g dien. A. 2OO7: rad/s. B. rad/s. SOTT •'•f^. C. IOOT: rad/s. i •• Huang dan +C = C, =^ tan(p, = ^ ^' = D . lOjtrad/s. \""r" ' ' \ ^ K =Z L -Zci ;y. C. 100/3 rad/s. «o = ^ ( « i + « ) ^ ' - S ' ^ ' =2,5(of =>o), =:10x/iO( rad/s) cuon cam thuan ccS dc) t u cam 1/n H . Ne'u dat mc)t t r o n g cac dien ap xoay chieu sau day vao hai dau doan mach trC'n thi c u o n g dc) hieu d u n g r^,;.j mach kVn nha't iVng vcM dien ap nao? C. u = U«cos(957rt) V. ^' + Uc = max Z(22 = — ; ^ n 71 ^»^' . | D . u = Uocos(707tt) V. , " • ; ' => — = 1(1^"' • (o^LC, = ^ co^ --^ B. u = Ui)Cos(857tt) V. Huang dan ^/->Z(2i = '''''' . Cau 79: Doan mach ncVi tiep g o m dien tro, tii dien co dien d u n g 0,l/7i mV va A . u = U()Cos(1057it)V. 2,5 D . 12,5^/lO rad/s. Hmhtg dciu dupe. K h i C = C: = OAlu mF thi d o n g dien tre pha K/4 S O v o i d i e n ap hai dau " vao hai dau doan mach g o m dien tro thuan R, cuon cam thuan co tu cam Cau 76: Dat dien ap xoay cliieu vao hai dau doan mach A B no'i tiep g o m dien ' =0,14 Cau 78: Dat dien ap xoay cliieu u = Uocostot (Uo k h o n g doi va co thay d o i duc)c) C0,|, = VC0,C02 => f,|, ^ ^ .7 LC U c m a x ^ Z L =(02L = Z , TT =-, = rr> CO = 1007c(rad/s) Gang gan v i t r i cong h i f d n g I cang Ic'in chi can so s a n h CO3 = 95:1 rad/s va CO4 = 10571 rad/s. ^" .'^^ :,,„:, •, rg- Cau 77: Dat dien ap xoay chieu vao hai dau doan mach A B n o i tiep g o m dien tra R, cuon day cam thuan L va tu dien co dien d u n g C thay d o i d u g c . Khi ' C = Ci t h i d o n g dien som pha n/4 so v o i dien ap giica hai dau doan machK h i C = Ci/6,25 t h i dien ap hieu d u n g giua hai tu cue dai. T i n t i he so cong sua't mach A B k h i do. A . 0,14. :? , •! ••;•••;/• B.0,71. C.0,8. D . 0,9. | HuOltg dmi ';'' +C = Ci =^tan(pi = ^ i - ^ ^ = t a n y =:>Zc, = Z L + R ' , . ^ ^ COQ = C ) ' r=> (IOOTT)^ = ( ' --^ { ' * 105,371 > CO4 = > I3 < I4 ' -i r'ii' Cau 80: M o t doan mach A B g o m doan A M va M B mac noi tiep. D o a n A M g o m tu dien C noi tiep vcVi dien t r o R, doan M B chi co cuon cam L . Dat vao A B m o t dien ap xoay ciiieu chi co tan so'goc (o thay d o i d u g c thi dien ap tuc t h o i tren A M va tren M B l u o n l u o n lech pha 7r/2. K h i mach cong h u o n g t h i dien ap tren A M va M B co cung gia trj hieu d u n g . K h i o) = coi thi dien ap tren A M ccS gia trj hieu d u n g U i va tre pha so vc>i dien ap tren A B m o t goc a i . K h i co = (02 thi dien ap hieu d u n g tren A M la U2 va dien ap tiic thai tren A M lai tre pha h o n dien ap tren A B m o t goc a2. Bie't a i + a2 = TC/2 va +C = - - r - = > Z c = , Z c i - , ( Z L + R ) 6, 2n U i = 0,75U2. T i n h he so cong sua't cua mach l i n g v o i coi va C02. , ,-,7 *\'tr., fi-V A . 0,75 va C. 0,75 va 0,75. 0,45. B. 0,45 va 0,75 , . . • D . 0,96 va 0,96. Huang divi ;; 322 + U c = max , ( Z L + R) = ^ Z^ ^ Khi cong hMng U ^ M = U ^ B = > U R = U, ' 323 la 92,0%. Biet dien tro suat ciia dong nho hon dien tro suat ciia nhom 1,47 TraSng hap Mt k i : .Ur cogR = — {•MY>r rr,(p = ^ a ---9^0 u " =? => cos(p = ssin2a inza , AM Ian. Neu dung day dan bang dong cung kich thuoc voi day d i n bang nhom noi tren de thay day nhom truyen tai dien thi h i | u suat truyen tai di^n se la MB T H I : cos iii; Cau 82: Hieu suat ciia qua trinh truyen tai dien nang tren day dan b3ng nhom U sinp = iii- ; • r_ A. 92,5%. n')ih !:n cos(p2 = 0,96 ; • • ^/ ^ /; - ' \'' ' PR, I-H1 = PR: 1-H, = l-Hi_Ri 1-0,92 1-H, 1-H, R, = 1,47 =:>H2 =^0,946 U^cos^cp Cau 83: Mot may bien ap c6 loi do'i xung gom n nhanh nhung chi c6 hai nhanh dugc qua'n hai cuon day. Khi mac mot cupn day vao dien ap xoay chieu thi cac duong sue t u no sinh khong bi thoat ngoai va dugc chia deu cho hai nhanh lai. Khi mac cuon vao dien ap hieu dung U thi a cuon de ho c6 dien ap hieu dung U2. Khi muc cuon vai dien ap hieu dung U2 thi dien ap hieu dung a cuon dg ho la A. U(n + l)-2. B. U ( n - l ) - . D. U ( n - l ) C. Un-2. Huang dan 02 = Cau 81: Mot mach xoay chieu RLC noi tiep chi c6 tan so f dong dien thay doi dirge. Khi f = 12,5 Hz va f = 50 Hz thi cong sua't tieu thu cua mach nhu nhau. Thay doi f cho cong suat toan mach Ion nhat th' thai gian s c6 bao nhieu Ian cuong dp dong dien qua mach bang 0? A. 50. B. 15. C. 25. Pi = P2 ^ I , = I2 ^ R2 + co,L =>f = 7W = 25(Hz) (24 'ft a A f C O TT L M »2Cj = max =>(o = — =^0) =(0,0)2 M ^ n % J J o ( ( i wC (n-1) (n-l)Ni El (n-1) U2U'2 _ N2 N,02 N2O', (n-1)' (n-l)N2 U2.U'2 U.U2 (n-1)" u U ' , =• ' (n-1)" n,,f,v,v , AB gom R, cuon cani thuan L va C mac noi tiep. Khi roto cua may quay deu voi toe Ian lugt ni vong/phiit va n2 vong/phiit thi cuong dong dien ^ R2 + coL - U2 _ N2O2 _ Cau 84: No'i hai cue ciia may phat dien xoay chieu mot pha voi mot doan mach D. 75. Huong dan O2 = O, hieu dung va tong tro cua mach doan m^ich AB Jan luct la Ii, Zi va I2, Z2. Biet I2 = 411 va Z2 = Zi. De tong tro ciia doan mach AB c6 gia t n nho nhat thi roto ciia may phai quay deu voi toe bang 480 vong/phiit. Gia tn ciia ni va n2 Ian lugt la A. 300 vong/phiit va 768 vong/phiit. V B. 120 vong/phiit va 1920 vong/phut. => Tron^^ chu k i dong dien = hai Idn C. 360 vong/ phiit va 640 y^ng/phut.#^ => Trong s dong dien = Ola 25.2 = 50 idn D. 240 vong/phiit va 960 vong/phut. 325 Bo trp kien thiic V$t li LTBH tren henh VTV2. t^p - Chu van Huang f= E = Bien Q^U 87: D i e n ap h i ^ u d u n g giua hai cue cua mot t r a m phat di§n can tang len dan = o ) | => n2 = n i .CO = 27lf 60 N2TrfO, l2=4Ii a)2L- V2^ cojC •cof =0,25 (0, = 0,5cO() => n j = 0,5n() = 240 =i> n2 = n , = 960 Z| = (oL = 1OOQ; Z c = bao nhieu Ian de g i a m cong suat hao p h i tren d u o n g day tai dien 100 Ian, n = xnj „^,,,, ^ , , ,;, ^ XZL-^C 276 ^. i 2x j ,; xE h • = max ( 877 2^ x , A ; n = xn] = x 576, x , . (v/s) • N = 2000 327 Cau 89: M o t may phat dien xoay chieu mot pha c6 d i e n t r o t r o n g k h o n g dang Huang ke, mac vao doan mach n o i tiep RLC. K h i toe d o quay ciia roto bang n i hoac n2 t h i c u a n g d o hieu d u n g t r o n g mach c6 cCing gia t r i . K h i toe d o quay cug roto la n(i t h i c u o n g hieu d u n g t r o n g mach cue d a i . C h o n he t h i i c d u n g . A. n() = (nin2)"-\• • ' - B. no^ = a5(ni2 + n22). • C. nir2 = 0,5(nr2 + n2-2). „^ Huong ' " E = NOn ^/2^V2 + n2j A. D i e m C each d a u A m o t doan A. 25 k m . ; CO " B. 50 k m . C. 75 k m . Huong sib; ^ B.220. C. 250. Huang P- Pcos^ D. 85 k m . dan D e h d d a u B : x - f R = — = 75Q=:>R = - x I D o a n m a c h dKu B : 2x AC = N e u dat ae m a y tai nha may dien thi cung cap d u d i e n nang cho cp P- , , D . 200. •2x + dm P^R 16U^ cos^ cp P^R 64U^ cos^ (p 100 R.(200-2x) U 500 R + (200-2x) Q A B = 25km (75-2x)(200-2x) 500 275 - 4x X = 25Q 100-x •— = 192P, B P = 200Po 100- = 198R X C a u 93: M o t m a y bien ap eo loi d o i x u n g g o m ba n h a n h n h u n g chi c6 hai " : D i e n nang d u g c t r u y e n t u may tang ap dat tai A toi m a y ap dat tai n h a n h duoe qua'n hai cuon day. K h i mac m o t cuon day vao d i e n ap xoay B bang day d o n g tie't dien t r o n d u o n g k i n h cm v o l t o n g chieu dai 200 k m . chieu t h i cac d u o n g sue t u d o no sinh k h o n g bj thoat ngoai va dugc C u o n g d o d o n g dien tren day tai la 50 A , cae eong suat hao p h i tren d i r o n g chia deu cho hai n h a n h l a i . K h i mac cuon vao dien ap hieu d u n g 60 V day tai bang 5% cong suat tieu t h u B. Bo qua m o i hao p h i t r o n g cac may thi cuon k h i cte h o eo dien ap hieu d u n g U2. K h i mac cuon v o i dien ap bien ap, coi he so cong suat cua cac mach so cap va thtr cap deu bang 1, hieu d u n g U2 t h i dien ap hieu d u n g cuon k h i de h a la dien t r o suat cua d o n g la 1,6.10 « Q m . Dien ap hieu d u n g may t h u cap cua may tang-ap c? A la A. 43 k V . 528 = 41000(V) n g u o n la 0,168 A . K h i dau B h o t h i c u o n g d o n g d i e n qua n g u o n la 0,16 , d u d i e n nang Ian l u o t cho 192 may hoat d o n g va 198 m a y hoat dong. P,t = P - A P = 0,05 k h o n g d a n g ke. K h i l a m dc:)an mach dau B t h i c u o n g d o d c n g dien qua .J. Ian lu'ot m a y tang ap c6 ti scY v o n g day N2/N1 = va N2/N1 = t h i ncxi tieu A. 280. 0,05 t o n g cong cua d u o n g day la 200 Q. D o day each dien k h o n g tot nen tgi m o t Cau 90: D i e n nang t r u y e n tai t u nha may phat dien den n o i tieu t h u . N e u d i i n g thu 50.41 d i e m C, n g u o i ta d u n g n g u o n dien eo suat dien d o n g 12 V, d i e n t r o t r o n g V \ I,R d i e m C nao d o tren d u o n g day c6 hien t u o n g ro d i e n . De phat hien v i t r i C f A P = i f R = 0,05PB = , U , I | ^ U j = U = U j + I j R = 41.10-^50.41 = ( V ) * ( k V ) V2 Z ^ rL 71(0,5.0,01) 7r(0,5df dan CO l l S 200.Kr ~ ( Q ) -8 Cau 92: M o t d u o n g day tai dien g i i i a hai d i e m A, B each 100 k m . D i e n tro -co NOn V2 = 1,6.10 Dien dp diXa ten diCdng day d A : .,ll,!r,i1 = D . nu = 0,5(ni + n2). f = n p =>(o = 2ni = 2npn En R = p— = p diin , , P !2 JvV. .V: {. C. 40 kV. A. 15 V. B. 60 V. x D . 20 k V . C. 30 V. Huong HD: -1 ^ ^ D . 40 V. ' ' ' ' dan U'2 =15V 329 •xiry'rrwnTivrv-a-rrTr-Tanmg-r,^ l a u 94: M o t thiet bj dien diroc dat d u o i dien ap xoay ciiieu u = 200':oslOOnt (V), t t i n h bang giay (s). Thiet bj ciii boat d o n g i 2.10 = ^ • • 13 = 6cos cot-- f = - ^ = 12,5=>(o = 27:f = 257t 60 E > '.li'r; . i i = 6cos((i)t) = 372 va dang tang A. C = — ^ 257T.80 2.V2VR2+(10-Zcf ^ ^ 5^ ^ = r ^ R = 30Q Day c h i u dupe c u o n g dp d o n g dien hieu d u n g toi da la A . Bie't nhiet ^ l u p n g to.i mdi t r u o n g x u n g quanh t i le thuan v o i d i e n tieh mat ngoai eua =-.lO^^F 7C day. Ne'u day eo d u o n g k i n h m m t h i day m o i ehju dupe c u o n g d p d o n g dien hieu d u n g toi da la ^ A . 32 A . R Zau 96: D o n g co k h o n g d o n g bp pha mac h i n h sao, k h i d o n g eo hoat d o n g B. A . ,. - ^ d i e n cac cuon day 1, va Ian l u p t la 0, 27r/3 va -27r/3. Vao t h o i d i e m Tidj Q = k7ld2i = 24 A . D. A. Huong dan Q = k7rd,URiI?t = p ^ I ? t b i n h t h u o n g a d i e n ap 200 V thi eong sua't tieu thu cua d o n g co bang 1620 72 VV va he so eong sua't la 0,9 eho m o i pha. Pha ban dciu eua d o n g , R2l2t = p A - l t nd2 ill 41? , , ,; I9=ll d2 Ui; 1,5 1,5 = = 24A 10,5; 331 Cty Tisnii nirv nx'vii Cau 99: Neu toe d o quay cua roto tang them v6ng/s thi tan so ciia d o n g dien d o II = 0 ( , ) ^ + 400(0,1)2 : ! = , V may phat tang t u 60 H z den 70 H z va suat dien dong hieu d u n g d o may phat thay d o i 40 V so voi ban dau. H o i neu tiep tuc tang toe cua roto Cau 102: M o t may bien ap l i t u o n g luc m o i san xuat c6 ! i so d i e n ap hieu d u n g them v6ng/s nua thi suat dien dong hieu d u n g may phat la bao nhieu? giOa cuon so cap va t h u cap bang 2. Sau m o t t h o i gian s u d u n g d o l o p each A . 320 V . d i e n kern nen c6 x v o n g day cuon t h u cap bj noi tat, v i vay t i so d i e n ap hieu B. 240 V. C. 280 V . Hu&iig f, = n p = 60Hz f = np: D.400 V. dan d u n g giua cuon so cap va t h u cap b3ng 2,5. De xac d j n h x n g u o i ta quan them vao cuon t h u cap 135 v o n g day t h i thay t i so d i e n ap hieu d u n g cuon fn = f2 = ( n + l ) p = H z J ' ^ | p = 10 so cap va t h u cap bang 1,6. So v o n g day bj noi tat la f3 = ( n + ) p = 80Hz A. X = 50 v o n g . N2nf Dap an C A. \ u., , , M . j y rv^UK "I I = , ( A ) => P(„ = I R = 5,375^32 = 1584,2W > 178W 334 42) le t h u a n v o i chieu dai cua day). Do su co, d u o n g da / bi ro d i e n tai d i e m Q cong sua't cua d o n g co la 0,9 va cong sua't hao p h i nho h o n cong sua't co hpc I = 1(A) y day CO d i e n t r o tong cong Q (coi day tai dien la d o n g cha't, r o dien tro ti •>•) 'I ' , ' 1, ' * ' I » 'AM ( ( jiiy !4>i (J,)^;'. / \ I * ', iifi < (1 - / I 1 , ' ' ill , . , ^ , I, . ^ , t A ! • , 331 [...]... •:yY;, Chuy:_ ' ; • '• ^ COC, 2 1 7 © i L i C i = 1 = ^ — - = (OiLi : „; :.::, ^1 Neu cho lien he L thi khu C: • » 2 L 2 C 2 1 — : 50 100 20 0 *r « X Khi mach R i L ^ C j noi tiep R2L2C2 xdy ra cong huang ta c6: wL, + w L j = • CO ( L j +1 .2) = a»b;3;wwti C0C2 bv C0?L,C,=1:::>L, + —!— 0)C2 >i ;\s U^R =r R = — R = => 40 = (R + r )2+ (Z, - Z c f R2 -21 0R + 20 00 = 0=> J- s , 5 (R +20 )2+ (60 -20 )2 R = 10(Q) ,:,vyb => Chon B R = 20 0(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... 100 V 2 ( V ) ) ) 30 V i du 5: D a t dien ap xoay chieu u = 22 0 ^ /2 coslOOTit (V) vao hai d a u d o a n mach A.i tren doan mach chua RL2 A i = 2N/2cos(1007it + 7 t / 6 ) ( A ) v a U i^^^ = WO %/2Z30x(30 + i ( 3 0 - 0 ) ) Trenmanhinh y/ft TnmnnrvDVVHKltang u = iZ = ^ Z ZL = dan _ 6 _ x (100 + 1(100 -20 0)) = 100^y2Z lOOi ^ ^ r, 12 41 Cty TiyHHMTVDVVnKhang V^t li LTDH tren k&nh VTV2, t^p 2 - Chu TTTT... 0 : u , i C l i n g p h a A 0,168 lit ; \,: B 0 ,22 4 lit C 0,1 12 lit D 0,056 l i t Huong ^an Q i / 2 = 2 ^ = 2 - ^ = 0, 02( C) ft) ^ t Qi /2 n , 2 = ^ : ^ l l , 2 T 96500"" 0, 02 96500 "2 • IOOT: phan chua d u n g djch H2SO4 v o i cac dien cue t r o T i n h the tich k h i 0 dieu kien tieu chuan thoat ra trong thoi gian 16 p h u t 6 m o i dien cue B 0, 023 5 lit ' C 0,047 lit , U UR UL UC C u o n g d... U L va = 50V2 V Ian luot A.I2V5V D.UC-UL = 100V2 V C.30V2 V D 60 V Cdch 1: ; I2 ^ = 3 1 , ; i j som pha hon u; -2C U2LC = U 2 L - U 2 C = U l R z O 3 Z L - ZC = R UILC = U I C - U H = U2K r : i > Z c - Z l , = 3 R R = t a n — = > U C - U L = 100(V) IR 12 tre pha hon u; I , 1 12 (1) (2) Tu (1) va (2) => Z L = 2R; Zc = 5 R Ban dau tan ( - c p i ) = ZL-ZC 1 u OKL Z = Z RL VR" - X J R ^ + ( 2 R - 5 R )... la 20 W Gia tri R bang , = U | + ( U L - UC)^ p = I2R = 2K-.R C 15Q Huong dan ^ D 2 0 Q - ,X tieu thu cua doan mach la A .24 0>y'3W Cdchl: B. 120 W C 24 0 W D 120 >/3 W • • u = 120 sin 1007rt + - j = 120 cos lOOnt-V 3; 6, (V) i = 4cos 100TUt + - ( A ) 6) 3 UR = 40(V) \ Cdch 2: Goi i* la so phuc lien hop cua i thi cong suat phuc: P = - i u 20 = — =^ R = 80(Q) =^ Chon A R V / R2 ' P = UIcoscp = 60N /2. 2> /2 C... 12' J d u o c ket qua EE cos 0,84 nghia la coscp « 0,84 => Chon B doan mach X Dat vao 2 dau mach m o t dien ap u = 120 N /2 cosl007:t (V) t h i c u o n g do d o n g dien qua cuon day la i = 0,6 V2 cos(1007:t - 71/6) ( A ) T i m hieu (50 + 5 0 i ) dien ap hieu d u n g giua 2 dau doan mach X A 2 4 0 V 20 0Z- B. 120 N/3V C.60^/2V D. 120 V Huong dim ux = u - U L = u - I Z L = 120 >y2 - ( 0 , 6 V 2 Z ~ 30 )20 0i... la 50 \ /2 Q va d i e n ap som pha hon d o n g dien la n/4 20 0 ' lOO N e u d o n g dien qua mach c6 bieu thuc 1 = 2 V2 cos(100Tit + 7t/6) ( A ) t h i bleu thuc dien ap gii>a hai dau doan mach la A u = 60cos(l OOKt + 571/ 12) (V) B u = 30 V2 cos(1007it + 7i/4) (V) C u = 60cos(1007rt - 7i/4) (V) D u = 30 N /2 cos(1007rt - 57r/ 12) (V) 2^ /2Z — TC 12 Huong dan u = i.Z = 2 V 2 Z - ] x ( l 5 + i ( 2 5 - 1... : UAM = 50 V2 COS(1 OOnt - 7Tr/l 2) V va UMB = ISOcoslOOnt (V) d o n g d i e n den gia t r i CO bang H e so cong suat cua doan mach A B la A A 0,86 B.0,84 0.0,95 D 0,71 2 COg B 0 ,25 COQ C 0,5 COQ D 4coo thUc V$t It LTDII trphtSn Ht'ni hcnh C t r Tiyilll MTV D VVn VTV2, t^p 2 - Chu VMii isk-ri Huong dan Z[ =W(,L (i)C = 20 (a) j^hi f = 2 f, t h i Z L 2 = 2 Z L , 20 L= - >Z|, ^50- + 2, 25.Zr, =• hay... 20 0N/2Z-~ 20 0-j2Z~n 1007tt + - 12 A u = 100 V2 cos(1007rt - 1171/ 12) (V) B u = 100 V2 cos(1007tt + ll7t/ 12) (V) C u = 50cos(1007it + 7t/ 12) (V) D u = 50 N /2 cos(1007tt + 7t/ 12) (V) ( V ) => Chon A Huang du 7: Cho d o a n mach xoay chieu noi tiep theo d u n g t h u t u g o m cuon cam t h u a n 1 CO d o t u cam L i = 0,1/?: ( H ) , d i e n t r o t h u a n 40 Q va cuon cam t h u a n 2 C O do t u cam L2 . Chude2. :: 1: MAY DIEN BAI TOAN LIEN QUAN DEN MAY PHAT DIEN XOAY CHIEU 1 PHA 200 BAI TOAN LIEN QUAN DEN MAY PHAT DIEN XOAY CHIEU 3 PHA 211 BAI TOAN LIEN QUAN DEN DONG CO DIEN . + (UL-Uc)' Vi du 13: Doan mach xoay chieu noi tiep gom dien tra thuan R, tu dien C va cuon cam thuan L. Dat vao hai dau doan mach mot dien ap xoay chieu on djnh thi dien ap hieu dung. coC.U^j;'="'^y; =.k = ^^I,=l,2V2(A)=>ChonA. Zc [l2=(02CU2 Ij (0|U, Vi du 3: Doan mach dien xoay chieu tan so fi = 60 Hz chi c6 mot tu dien. Neu tan so la h thi dung khang cua tu