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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 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 = (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 + — 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 = — 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 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 + - 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, = —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: ' 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(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 = — •, ' 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 B6 trp kiSn V4t It L T D H thiic tren kenh VTV2, t^p 2- Chu cty munnrvDvvnKhang Van Blgn Huang dan M N = 100cos30° =5073 ' ' ' M B = M N V =50V6(V) AMNB Id tarn side vuong can taiN :=>{ ^ ^ n U M R sam hcfn U NMBR la — vift au 40: Doan mach dien xoay chieu tan so fi = 60 Hz chi c6 mpt iu dien Neu tan so la b thi dung khang ciia tu dien tang them 20% Tan so A f2 = 72Hz B f2 = 50Hz C £2 = 10 Hz D f2 = 250Hz Huang dan ^ = = 0 % + 20% = 1,2 =^ f2 = = 50(Hz) • ' Zci 12 1-2 {,\ Cau 41: Mot tu dien phang khong hai ban song song each mot khoang d dugc noi vao nguon dien xoay chieu thi cuong hieu dung qua mach la 5,4 A Dat vao tu dien va sat vao mot ban tu mot tarn dien moi day 0,5d c6 hang so dien moi e = thi cuong hieu dung qua tu la A 2,7 A B.8,1A C.10,8A.P.7,2A •„V Humgdan , y,,,, > + - = 100V3cos lOOnt U M R =50V6.N/2 COS lOOTit U Ci=Cn = 9.10^.47id • = 2C0 9.10^.471.0,5d E.S QA CintC2 9.10^.471.0,5.d =>Zr = Cau 39: Dat di^n ap xoay chieu u = \]yi2 coslnit (V) vao hai dau doan mach noi tiep gom dien tra R, cuon cam thuan L va tu dien C thi dien ap hieu dung tren R, tren L va tren C Ian luot la 136 V, 136 V va 34 V Neu chi tang tan so cua nguon Ian thi dien ap hi^u dyng tren dien tro la A 25 V B.50V C.50^/2V T D 80 V.; ^ ^ 3' U = N / U I T ( I V ^ U ^ = ^136^+(136-34)2 ^ ^70^^^ UL=UR=>ZL=R R ^4 uf ,jr ZL=2ZL-2R=>U'L=2UR f = 2f: ^ ^ 306 =>I = - I o = - , = 7,2(A) Mif I i ' 1! t ' "•au 42: Dong dien xoay chieu chay qua mot doan mach c6 bieu th'vc i = 2>/2 cos(1007it + (p) (A), t tinh bang giay (s) Vao mot thai diem nao do, ' i = %/2 A va dang giam thi sau it nha't la bao lau thi i = + ^6 A? / ^^ A 3/200 (s) B 5/600 (s) C 2/300 (s) D 1/100 (s) ' Huong dan ^/2 V6 ' ~12 4"^4^6~4 200' ' + -A 0,5A 0,5AV3 Cau 43 (DH 2011): Mot doan mach AB gom hai doan mach AM va MB mac noi tiep Doan mach A M gom dien tro thuan R i mac noi tiep voi tu dien c6 dien dung C, doan mach MB gom dien tro thuan R2 mac noi tiep voi cuon cam •thuan CO dp tu cam L Dat dien ap xoay chieu c6 tan so'va gia tri hieu dung , khong doi vao hai dau doan mach AB Khi doan mach AB tieu thu cong suat bang 120 W va c6 he so cong suat bang Neu noi tat hai dau tu dien thi dien ap giiJa hai dau doan mach A M va MB c6 cijng gia trj hieu dung nhung l^ch pha y , cong suat tieu thu tren doan marh AB 64 =>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 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 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 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 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 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 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 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 , " • ; ' => — = 2 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,|, ^ ^ 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 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 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 ^ ^ 2 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 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 •>< C a u 106: M o t d o n g co dien xoay chieu co dien t r a day cuon la 20 Q, mach dien A 72Z, + j =4 Zc dien nang d u g c truyen tai den noi tieu thu N , each M k m Biet d i r o n g IOOI2 A 0,25 R + ( Z , - Z C ) ' xac d j n h v j t r i Q , trirdc tien n g u o i ta ngat d u o n g day k h o i may phat va tai CO dien r.p hieu d u n g 220 !>•• ^ -= R2 I rioo72f UV2 J =^ZC=2R;ZL=R D 300 V ^ luV2 1 IURLV2, + I - Cau 108 ( D H 2012): T i r m o t t r a m phat dien xoay chieu m o t pha dat tai v j t r i M , u KL C max < ^ U R L 2Z, + = R2 ' i'K ' >•) 'I ' , ' 1, ' * ' I » 'AM ( ( jiiy !4>i (J,)^;' / \ I * ', iifi < (1 - / I 1 , ' ' ill , , ^ , I, ^ , t A ! • , 331