Môn Vật lý và bổ trợ kiến thức luyện thi Đại học trên kênh VTV2 (Phần 2: Điện xoay chiều): Phần 2

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Nối tiếp nội dung phần 1 tài liệu Bổ trợ kiến thức luyện thi Đại học trên kênh VTV2 Vật lý - Phần 2: Điện xoay chiều, phần 2 giới thiệu tới người đọc kiến thức và phương pháp giải các bài toán cơ bản, điển hình, hay, lạ và khó về chủ đề máy điện. Mời các bạn cùng tham khảo.

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Nội dung Text: Môn Vật lý và bổ trợ kiến thức luyện thi Đại học trên kênh VTV2 (Phần 2: Điện xoay chiều): Phần 2

BS trpkien thtic V$t If LTDH t r e n kenh VTV2. t^p 2-Chu Van Bl6n CtyjmtH MTV i>VVHKhang Vl^t Huang dan Chu d e 2 . 27p '"^••"-t:: 10 f = n , p i = 27.2 = 54(Hz) => Chon D. •:f^iV , .... , o , • '^x: ^ Chi'i y : Khi may phat c6 so'cap cue thay dot Ap va so vong quay thay doi An (nen BAITOAN LIEN QUAN DEN MAY PHAT DifN XOAY CHIEU 1 PHA dot don vi la vdng/giay) thi tin/ thuoc triiv'ng hop delira chon dau '+' hay dau '-' An{vdng/s) Ne'u may phat c6 p cap cue n a m cham va roto quay v o i toe d o n v6ng/s thi trong cdc cong thuc sau : Hi =• ,, tan so d o n g d i e n do may phat ra: f = np . ^ ^ ^ Pi J, Ne'u may phat c6 p cap cue nam cham va roto quay v o i toe d o n vong/phut f2 = n2P2 - ( n i ± A n ) ( p i ± Ap) =^ Pi = ? V i d u 3: M o t m a y phat dien xoay chieu m o t pha phat ra d o n g dien c6 tan so'60 t h i tan so d o n g d i e n do may phat ra: f = ^ . Hz. Ne'u thay roto ciia no bang mot roto khac co nhieu hon m o t cap cue, Ne'u liie dau p h a p t u y e n eua k h u n g day h h o p v o i cam u n g tir B m o t goc m u o n tan so v a n la 60 H z t h i so v o n g quay cua roto t r o n g m o t g i o thay doi a t h i bleu thue tir t h o n g g u i qua mot v o n g day O i = BSeos(cot + a). 7200 v o n g . T i n h so cap cue cua roto c i i . > ' "- ^ Ne'u cuon day c6 N v o n g g i o n g nhau, t h i suat dien d o n g xoay chieu trong A. 10. B. 4. C. 15. D . 5. cuon day la: e = - N ^ ^ = ojNBSsin(rj)t + a ) . Huang dan ,, ,, . .. 7200(o6n^) 7200(uon^) , ^ . u . . . . , b rfnn . • Ttr t h o n g cue dai g u i qua 1 v o n g day: cI>o = BS. :: j .,r} ^ri = = = 2{vongls) ynouv rr5 iv (r> on : Bien d o cua sualt dien d o n g la: E(, = coNBS. Uftn 0£ / ii;GI rs V I:- EQ mNBS lob ^^'vfiT' W'^ Mi('h:c':>'£'v f] = n ] p i = 6 0 ( H z ) = > n | = — H Sua't dien d o n g hieu d u n g : E = Pi •'•6 • ' K h i p2 = p i + 1 ma f2 = f i nen toe d p quay phai g i a m tuc la n2 = n i - 2: Chuy: .^>c-,,'.u, ^.j, ^...j-jni, >^. v , ^.I/^M h = "2P2 = ("1 ~ 2 ) ( p i +1) • • ' ,H>,' i.i£K Ne'u luc dau n ciing huvng voi B ih'i a=0 (mat khung vuong goc vai B ) . 60 Thay h = 60 H z va n j = — ta duoc: 60 = -2 (PJ + 1 ) P ] = 5 => Chon D. Ne'u liic dan n nguvc huvng voi B thi a= K (mat khung vuong goc voi B j . Pi Pi Nculucdau i i vuong goc voi B thia = ±7r/2 (mat khung song song voi B j . V i d u 4: M o t k h u n g day det h i n h v u o n g cgnh 20 cm co 200 v o n g day quay deu V i d u 1 : (CD-2010) M o t may phat dien xoay chieu mot pha c6 p h a n cam la rotd trong t u t r u o n g k h o n g d o i , co cam u n g 0,05 (T) v o i toe d p 50 vong/s, x u n g n quay v o i toe d o 375 vong/phut. Tan so cua sua't dien d o n g cam u n g ma ma\ quanh m o t true nam t r o n g mat phc^ng k h u n g d a y va v u o n g goc v o i t u tr phat tao ra la 50 H z . So cap cue ciia roto b3ng t r u o n g . Tai t h o i d i e m ban dau phap tuyen cua k h u n g day ngug-c h u o n g v o i A. 12. B. 4. C. 16. D . 8. « fiso- t u t r u o n g . T u t h o n g qua k h u n g 6 t h o i d i e m t co bieu thuc >(i , , ' , , Hudtig dan • :l v* sw A. (j) = 0,4sinl007tt ( W b ) . B.^ = 0,4cosl00Ttt (Wb). > V T u cong thuc f = => 50 = ^ =^ p = 8 ' ' ' C. ChonD. Huang dan o) = 271.50^1007t(rad/&); l^f.q ,i^m iMi^in-'^'-yr ' V i d u 2: H a i may phat dien xoay chieu m o t pha phat ra d o n g dien xoay chicni C O cung tan so f. M a y t h u nha't c6 p cap cue, roto quay v o i to'c d o 27 vong/^ O = NBScos{1007tt + n) = 200.0,05.0,2^ cos (lOOjtt + 7t) M a y t h i i hai c6 4 cap cue quay v o i toe do n v6ng/s ( v o i 10 < n < 20). T i n h f. O = 0,4cos(1007tt + 7t)(Wb) A . 50 H z . B. 100 H z . C. 6 0 H z . D. 54 H z . n^ChonC. 201 200
V i du 5: ( D H - 2 0 n ) Mot khung day dan phang quay deu voi toc do goc . ^Ju 8: Mot khung day dan det hinh tron ban kinh 1 cm gom c6 1000 vong, quanh mot true co djnh nam trong mat phang khung day, trong mot t i i uay voi toe do 1500 (vong/phiit) quanh mot true nam trong mat phang cua truong deu c6 vecto cam ung tu vuong goc voi true quay cua khung. Sua't khung day, trong mot tCr truong deu eo cam ung tu 0,2 T c6 huang vuong dien dong cam ling trong khung c6 bieu thiic e = Eocos(cot + nil). Tai thoj rrdc voi true quay. Tinh sua't dien dong hieu dung trong khung day. diem t = 0, vecto phap tuyen cua mat ph^ng khung day hop voi vecto cam A.8(V). ' B.5(V). C.7(V). D . 6 (V). ung tir mot goc bang Huongdan A. 45". B. 180". C. 90". D. 150". ..I^ = 25(Hz) Huang dan ^60 O = NBScos(Mt + a) {V- ' ' N.27tf.BS _ N.27rf.B7tr^ _ 1000.271.25.0,2.71.10"^ ~ 7 (v) =i> Chon C V2 " sl2 ~ ^/2 «^ ( ) =^ on . 71 71 e = - O ' = o)NBSsin((ot + a) = EQ COS a)t + a - 7 t / 2 •a = — : • a = 71 Vi dy 9: Phan cam ciia mot may phat dien xoay chieu mot pha c6 hai cap cue. 2 2 Cae cuon day cua phan ung mac noi tiep vao eo so vong tong eong la => Chen B. 240 vong. Tir thong cue dai qua moi vong day va c6 toe do quay cua roto V i du 6: Mot khung day det hinh chu nhat c6 200 vong, dien tich moi vong phai CO gia tri the'nao de sua't dien dong c6 gia trj hieu dung la 220 V va tan 300 cm2, dugc dat trong mot t u truong deu, cam ung tir 0,015 T. Khung day so la 50 Hz? CO the quay quanh mot true doi xung ciia no, vuong goc vol t u truong. Khi A. 5 (mWb); 30 (v6ng/s). B. 4 (mWb); 30 (v6ng/s). toe do quay bang M thi suat dien dong cue dai xuat hien trong khung day la C. 5 (mWb); 80 (v6ng/s). D . 4 (mWb); 25 (v6ng/s). 7,1 V. Tinh do Ion sua't dien dong trong cuon day 6 thoi diem 0,01 s ke tu Huang dan liic no CO vj tri vuong goc voi tu truong. f = np => n = — = 25(v6ng/s) > ,; ! » A.4V. B. 4,5 V. C.5V. D. 0,1 V. p , :„ • - ^ Huong dan E^^N27^^ 220.72 , , , o ^ 3 ( ^ , ) Eo = NcoBS =^ 0) = - •«79(rad/s) ^/2 V2 " N27rf 240.271.50 ^ , NBS ^ • ' nr =>Ch0nD. rh'V:--r:^5c F^S;-.".-:' Liig dau khung day vuong goe voi tu truong nen a = 0 hoac a = TI. Chu y: Nen mach dime noi kin va tong dien tro thuan cm niach la R thi cumig do Ta chon a = 0 thi e = E,, sin at ->e = 7,1.sin 79.0,01 « 5 ( V ) hieu dung, cong suat toa nliiet va nhiet luvng toa ra Ian luot la: , j,^^ => Chon C. E . = i;P = I 2 R ; Q = Pt = I^Rt • '> ' ^ 'V: ' Luu y: NeU may tinh dechedo D thi se triing voi dap sosai la 0,1 V! "' V2 R ' Vi du 7: (CD-2010) Mot khung day dan ph5ng det hinh chii nhat c6 500 vong Vi du 10: Phan ung eiia mot may phat dien xoay chieu mot pha c6 2 0 0 vong day, dien tich moi vong la 220cm2. Khung quay deu voi toe do 50 vong/giay day. T u thong qua moi vong day c6 gia tri cue dai la 2 mWb va bien thien quanh mot true doi xung nam trong mat phcing ciia khung day, trong mot dieu hoa voi tan so 5 0 Hz. Hai dau khung day noi voi di|n tro R = 1000 Q. t u truong deu c6 vec to cam ung tu vuong goc voi true quay va c6 do Ion Tinh nhi#t lugng toa ra tren R trong thoi gian 1 phiit. 0,2 V2 /TI (T). Suat dien dong cue dai trong khung day bang A . 4 1 7 J. B.474J. C.465J. D.47CJ. A.110N/2V. B.220V2V. C.llOV. D.220V. ' Huongdan I . • Huongdan (0 = 27:f = 1007r(rad/s) ^' 'vP-^^-^/^C^^^^^^^^^^^^ ' Mot t u truong deu nen p = 1 va f = np = 50(Hz). O T^Rt Ept (NcoBS)^ t _ (200.10071.0,002)^ .60 ^ y: 2R 2R 2.1000 =^ Eo = N.2nf.BS = 500.27t.50.^^^.220.10~^ - 220>/2 (V) 71 , =>ChonB. . , •;. . f ' Chon B. 202 203
Cty TISHH MTV D VVH Khang Vipt V i du 1 1 : Mot vong day c6 dien tich S = 0,01m2 va dien tro R = 0,45Q, quay dgq du 13: Neu toe do quay cua roto tang them 1 v6ng/s thi tan so cua dong vai toe do goc co = T O O rad/s trong mot tu truong deu c6 cam ling tu B = 0,1^ dien do may phat ra tang tu 60 H z den 70 H z va suat dien dong hieu dung ' xung quanh mot true nam trong mat phang vong day va vuong goc vol ca^ do may phat ra thay doi 40 V so voi ban dau. Hoi neu tiep tuc tang toe do duong sue tu. Nhiet lugng toa ra trong vong day khi no quay dugc IOOQ ciia roto them 1 v6ng/s nOa thi suat dien dong hieu dung do may phat ra la vong la bao nhieu? A. 1,39 J. ' B. 0,35 J. ' C . 2,19 J. D . 0,7 J. A. 320 V. ;,. ; n B. 240 V. C . 280 V. '' ' D . 400 V . Huong dan • - 7 7 " Huang dan f i = n p = 60(Hz) 1 Jn = 6 . .:- • t = nT = n — = 1 0 0 0 . — = 207t(s) - .;S.(X!Ot -'-miii-iLlA iP.i7.r:.v. (0 100 f2 = ( n + l ) p = 70(Hz)J ^ | p = 10 J' v^:, ',, Cachl: f = np: _NcaBS _ 1.100.0,1.0,01 2 . f3=(n + 2)p = 80(Hz) 80 1 -3 _ = ^ £ 3 = 3 2 0 ( V ) =^Ch9nA. ,b ; OK =^Q = m = -I^Rt = - .0,45.2071« 0,7(J) => Chon D.I E2-E1 40 70-60 {9 n : ir-i ' i u : , iisH r o M .T,0£',,() Vi E l =240(V) V i d\ 12: Mot may dao dien eo roto 4 cue quay deu vol toe dg 25 v6ng/s. Stato n 60 El each 2: n +1 70 E l + 40 n = 6(v/s) la phan ung gom 100 vong day dan dien tich mot vong 6.10-2 j^i^ ^am ung tu B = 5.10"2 T. Hai cue eiia may phat dugc no'i voi dien tro thuan R, nhung n El 6 _240 ^ _ _ . E ' = 320(V) vao trong 1 kg nuac. Nhiet dg cua nuoc sau moi phut tang them 1,9". Tong n +2 E' 6+2 E' tro cua phan ung cua may dao di^n dugc bo qua. Nhiet dung rieng cua CM y: To'ng sovdng day cua phan leng N = ^' •. Neu phan ung gom k cuon day nuoc la 4186 J/kg.dg.TinhR. n w = 2n( = 1007:{rad/s) Vi du 14: (DH-2011) Mot may phat dien xoay chieu mgt pha c6 phan ung gom NwBS 100.100n.5.10"^.6.10~^ bon cuon day giong nhau mac noi tiep. Suat dien dong xoay chieu do may Eo *66,64(V) V2~ V2 72, phat sinh ra eo tan so 50 H z va gia tri hieu dung 100 72 V . T u thong cue dai 66,64\60 qua moi vong cua phan ung la 5/n mWb. So'vong day trong moi cuon day Q/r]a=-;rt = Q i i , u = c m A t " = ^ R = - « 3 3 , 5 ( Q ) =^ChonB. R crnAt" 4186.1.1,9 cua phan ung la A. 71 vong. •"' " / B. 200 vong. fi = np I =7 C . 100 vong. D . 400 vong. , . Huong dan Chii y: Khi toe d(i quay cm roto thay doi thi tan so': f2 = (n + A n ) p p =? P = 27tf = l 6 0 K ( r a d / s ) h'lB'A .J inn gro/' • • f3 = (n + An')p = ? E72 100.7272 cup g n u b u':iiH oh N- = 400 : . N i = — = 100 2.ifiNOo E,= I O O K ^ I O " ^ V2 71 ^ ... , ^ En 27tfNO(, ChonC. -i: : - ' 7'"'': E21. 27if2NOo '"in. Suat dt^n dong hicu dung tuang leng: E = = —-j=— 72 Chu y: L R C 27:f3N
B S trp k l ^ n thiic V^t If LTDii tr£n k€nh VTV2. t^p 2 - Chu VSn BiSn Cty TNHH nrv O VVn Khang Vifl yji du 17: (DH-2010) Noi hai cue ciia mot may phat dien xoay chieu mot pha f = np => CO = 27tf => Z L = coL;Z(;; = vao hai dau doan mach AB gom dien tro thuan R mac noi tiep voi cuon cam f:'r:;'\Ha'V::.r thuan. Bo qua dien tro cac cuon day cua may phat. Khi roto cua may quay E= 0 x/2 deu voi toe do n vong/phut thi cuong do dong dien hieu dung trong doan mach la 1 A. Khi roto cua may quay deu voi toe do 3n vong/phut thi cuong Khin' = knthi E'= kE;Z'i = kZL;Z'c = — jj f ^ do dong dien hieu dung trong doan mach la >/3 (A). Neu roto cua may quay deu voi toe do 2n vong/phut thi cam khang cua doan mach AB la kE A.2RV3. B.2R/V3. C.RVS. D.R/-/3. R2 + kZ, Huong dan .(•.. , V 3 _ JR_ V i d u 15: Roto cua may phat dien xoay chieu mot pha c6 100 vong day, dien A p d u n g : 7 = 1< = 3.- tro khong dang ke, dien tich moi vong 60 c m l Stato tao ra t u tr'jong deu co '+(kZLf ,J ( cam ling t u 0,20 T. Noi hai cue ciia may vao hai dau doan mach gom: dien 2R Khi toe do quay tang 2 Ian thi cam khang cung tang 2 Ian: Z ' L = 2 Z L = tro thuan R = 10 Q, cuon cam thuan c6 he so tu cam L = 0,2/n H va tu dien V3 CO dien dung C = 0,3/n mF. Khi roto cua may quay deu voi toe do n = 1500 => Chon B. vong/phut thi cuong do hieu dung qua R la Vi du 18: Noi hai cue cua mot may phat dien xoay chieu mot pha vao hai dau A. 0,3276 A. B. 0,7997 A. C. 0,2316 A. D. 1,5994 A. doan mach AB gom dien tro thuan R mac no'i tiep voi tu dien. Bo qua dien ,,„ui:„:«,,r.,: y .iimi^^u Huong dan A .;, tro cac cuon day cua may phat. Khi roto ciia may quay deu »'6i toe do n vong/phiit thi cuong do dong dien hieu dung trong doan mach la 1 A. Khi f = ^ - 25(Hz) m = 27rf = 50n =^Z^=aL = 10(Q);ZL = — = — ( Q ) 60 roto ciia may quay deu voi toe do 3n vong/phiit thi cuong do dong dien ^^NcgSj00.50..0,360.10-^^^3 33^^^ hieu dung trong doan mach la 3\/2 (A). Neu roto ciia may quay deu voi toe v/2 V2 do 2n vong/phiit thi dung khang cua doan mach AB la A. 2 R V 3 . B. 3R. C.RVS. D . 1,5RV7. = s:0,2316(A) =>ChonC, •. . "^^^ > 2 ^ ( Z L - Z C ) Huong dan 2 V i d u 16: N o i hai cue cua mot may phat dien xoay chieu mot pha vao hai dau 7S 372 = 3. VR^+Z 3R Ap dung: Zr = doan mach mac noi tiep AB gom dien tro thuan R, cuon cam thuan L va tu I I 77 R2 + dien C. Bo qua dien tro cac cuon day cua may phat. Khi roto cua may quay deu voi toe do n vong/phut thi dung khang cua C bang R va bang bon ian Khi toe do quay tang 2 Ian thi dung khang giam 2 Ian: , I cam khang cua L. Neu roto cua may quay deu voi toe do 2n vong/phiit tlVi 1,5R cuong do hieu dung qua mach AB se Z'c=- Chon D. 2 77 A. tang 2 Ian. B. giam 2 Ian. C. tang 2,5 Ian. D. giam 2,5 Ian. Vi du 19: Mot may phat dien xoay chieu mot pha c6 dien tro trong khong dang Huang dan ke. Noi hai cue may phat voi cuon day c6 dien tro thuan R, he so tu cam L. R Luc dau: = R, Z L = Khi roto quay voi toe do n v6ng/s thi dong dien hieu dung qu?. cuon day la -J 1 A . Khi roto quay voi toe do 2n v6ng/s thi cuong do hieu duag qua cuon day la 2 7 M (A). Neu roto quay voi toe do 3n v6ng/s thi cuong do hieu = 2,5=>ChonC. dung qua cuon day la .-: - . I ' R2 + k Z L - A. 0,6 7 2 (A). B. 0,6 7 5 (A). C. 0,6 7 3 (A). D. 0,4 7 3 (A). V
B o t r g hien thiic V^t liLTDtl t r c n kdnh VTV2, t a p 2j-Chu V^n BiSn Cty TIMIII MTVDVVtl Khang Vift Huang dan trong mach ciang pha vol dien ap tuc thai giCta hai dau AB. Cuong do hieu 2E, ZLI=R dung khi do la I , =• • = l;l2 = • = 0,4V2 : +4Z^i El =RN/2 A.2V2 (A). B. 8(A). C.4(A). D. 2(A). Ll Huxmg dan 3E, 3RN/2 l3 = = 3 7 0 2 (A) => Chon B. . , ; v . / ZL-ZC • tan —: Zi - Z c =RN/3 : VR^ +9Z^i V R ^ - 9R^ tan(p = ' R 3 C/i« y: Ncu bai toan lien qiian den do lech pha hone he so cong sud't thi ta scrut ra ^R2+(ZL-ZC)' R2 + (RS/3)' Z, - Z c r =k • = 2- = 8 = > I ' = 8(A) tan (p = R kZ,-^ Zc dime he thirc ci'ia Zi, Zc theo R: R2 + R-^ 2Z, R 2 cos(p = /R-+(Z,,-Zcf - » Chon B. V i du 20: Mach RLC mac vao may phat dien xoay chieu. Khi toe do quay cua Chu y: Khi dieu chinh toe do quay cua wto deniqch cong huv'ng thi rwinig do hieu roto la n (vong/phut) thi cong suat laP, he so cong suat 0,5 N/3 . Khi toe dp dung chwa chac cue dai va khi cuvng do hieu dung cue dai thi mach chua elide eong quay cua roto la 2n (vong/phut) thi cong suat la 4P. Khi toe do quay cua huong.' • • '^^ ^"1- ! • •• ' ' ' « ^ T'' • roto la n ^/2 (vong/phut) thi cong suat bang bao nhieu? Vi du 22: Doan mach noi tiep AB gom dien tro R = 100 Q, cuon day thuan cam A. 16P/7. B. P>/3. C. 9P. D.24P/13. CO L = 2/71 H noi tiep va tu dien eo dien dung C = 0,1/7T mF. Noi AB voi may Htfoiig dan phat dien xoay chieu mot pha gom 10 cap cue (dien tro trong khong dang -!) t6\ vera ^ ke). Khi roto cua may phat dien quay voi toe do 2,5 v6ng/s thi cuong do coscp == . ( Z L - z c r = — (1) JR^ + ( Z L - Z c r dong di^n hieu dung trong mach la %/2 A. Thay doi toe do quay cua roto cho den khi trong mach c6 eong huong. Toe do quay cua roto va cuang do /ji\ T.->2 dong dien hieu dung khi do la »a < hf tn hi i^ll^j F 2 R2+(ZL-Zcr =k 4 = 4.- p A. 2,5 V2 v6ng/s va 2 A. '; B. 25 >/2 v6ng/s va 2 A. OP ..f R2 + kZL - R2 + 2Z, C. 25 V2 v6ng/s va 72 A. D. 2,5 72 v6ng/s va 2V2 A. St' .8 R R ^ 2R Hudnvddn *d£ ^ (2).Tu(l),(2)suyra: Z L = ^ 4'\ 'ixw ,rxV:f •• ' f = np = 25(Hz) => CO = 2ni = 507t(rad/s); Z L = loL = lOO(Q); Zc = — - 200(Q) R^ coC P" 16 I 7 =>E = I 7 R ^ + ( Z , . - Z C ) ' =200(V) , • ^^^^ qn.^ R R R2 + k'Z, - R2 + V2 Khi eong huang: 27if'L = - ^ -=>•f' = 2572(II/) = f72 k' V3 V2V3 27if'C 16. =^P" = —P =>Chon A. Ir, =>n' = n72 =2,572(i;6n^/s) ^: 7 V i du 21: Noi hai cue cua may phat dien xoay chieu mot pha vao hai dau doan E' = E72 = 20072 (V) =^ I ' = 1^ = 272(A) => Chon D. mach AB gom dien tro thuan R, cuon cam thuan va tu dien mac noi tiep. Bo qua dien tro cae cuon day cua may phat. Khi roto cua may quay deu voi toe '«u 23: Doan mach noi tiep AB gom dien tro R = 100 Q, cuon day thuan Ccim do n vong/phut thi cuong do hieu dung trong mach la 1 A va dong dien tiic '^o L = 2/71 H noi tiep va tu dien c6 di^n dung C = 0,l/7t mF. No'i AB voi may thai trong mach cham pha 7i/3 so voi ctien ap tuc thai giua hai dau doan ?hat dien xoay chieu mot pha gom 10 cap cue (dien tra trong khong dang mach. Khi roto cua may quay deu voi toe do 2n vong/phut thi dong dien P). Khi roto ciia may phat dien quay voi toe dp 2,5 v6ng/s thi euang do long dien hieu dung trong mach la 72 A. Thay doi toe do quay cua roto 208 . m..
B S trgklin thitc V^t li L T D H tren kenh V T V 2 . t^p 2-Chu V^n Bien CtyTimnnrvown Khang V/pt cho den k h i c u o n g do d o n g d i e n hieu d u n g t r o n g m a c h dat cue dai. To'c (j. v i dv 25: M p t m a y phat d i e n xoay chieu m o t pha c6 d i e n t r o t r o n g k h o n g dang quay cua roto va c u o n g dp d o n g dien hieu d u n g k h i do la ke, mac vao d o a n m a c h no'i tiep RLC. K h i to'c d p quay ciia roto b a n g n i hoac A . 2,5 N/2 v6ng/s va 2 A . : B. 10/^/6 v6ng/s va 8/V7 A . r\2 t h i c u c n g d p hieu d u n g t r o n g mach c6 c i i n g gia t r i . K h i to'c d p quay ciia C. 25 N/2 v6ng/s va V 2 A . D . 2,5 V 2 v6ng/s va 2 V 2 A . roto la no t h i c u o n g dp hieu d u n g t r o n g mach cue d a i . C h p n he t h i i c d i i n g . Huang dan A . no = (nm2)0'S. B. no^ = 0,5(ni2 + n22). C. no-2 = 0,5(nr2 + nr^). D . no = 0,5(ni + n2). f = n p = 25Hz=>co = 27if = 5071 ^ ' Huang dan Htiti Z L = coL = 1 0 0 ( Q ) ; Z c = ^ coC = 200(Q) ^ = ^R^+{z[-Zcf f = n p => CO = 2ni = 2npn (0 EQ _ N O Q i:>Ei=200(V) E= -co 72 ' , 1 xE 2x 72 7 2 R2 + c o L - coCJ D a t n = xtt] => I = - / 2^^ R2 + x Z i - 1 + X — •3-^ + 1 NcDn 1 X / V V Xy V x 1 = 72 1 1 L_R^ D a y la h a m kieu tarn i h i i c do'i v o i 2V6 8V7 5^6, .- -2 +1 X = - = > X = • 0 3 7 A ; n = xni = 3 (v/s) •Chon B . Vc 2 C 2 CO Vi 24: N o i hai cue cua may phat dien xoay chieu m o t pha v o i m p t doan 1 1 bien so'l/co^ => m a c h A B g o m R, cuon cam thuan L va C mac no'i tiep. K h i l o t o ciia may CO? CO2 4 J quay deu v o i to'c d o Ian l u g t ni vong/phut va m vong/phiit t h i c u o n g do • C h o n C. Hi t,f" 1 d o n g dien hieu d u n g va tong t r d ciia mach t r o n g doan m a c h A B Ian lupt la I i , Z i va h , Zi. Bie't I2 = 4Ii va Z2 = Z i . De tong t r o ciia doan mach A B c6 gia trj BAI TOAN LIEN QUAN D E N MAY PHAT D i f N XOAY CHIEU 3 PHA n h o nha't t h i roto cua may phai quay deu v o i to'c d p bang 480 vong/phut, Phuang phdp gidi Gia t r i ciia ni va 1x2 Ian l u a t la D i e n ap pha U P la dien ap g i i i a hai d a u m p t cuon ciia may phat. A .,300 vong/phut va 768 vong/phiit. D i e n ap day Ud la d i e n ap g i i i a hai dau day n o n g ciia m a y phat d u a ra B. 120 vong/phut va 1920 vong/phiit. '. . ^ v. ngoai. C. 360 v o n g / p h i i t va 640 vong/phiit. D i e n ap d j n h m i i c tren m o i tai U . ' > i' ., jD. 240 vong/phiit va 960 vong/phiit. • ry * Nguon mac sao - T a i mac sao • Huang dan •U = U p T U , U U 60 (If. N27ifOo E= P = Pl+P2+P3=I?Ri+liR2+l3R3 V2 A = Pt (02 = 4cO] => n2 = 4 n i 1 1 Nguon mac sao - T a i mic tam giac l2=4Ii C02L- -(OiL=>cof = 0 , 2 5 (B2C cojC LC U = Ud =Up73 u I1 :> COj = 0,5(0o Zj Z2 ^3 LC => n^ = 0,5no = 240 ( v o n g / p h i i t ) ; n 2 = 4 n i = 960 (vong/phiit) P = Pl+P2+P3=I?Ri+l2R2+l3R3 => C h o n D . A = Pt
B6 trjf Men thiic V^t li LTBII tren henli VTV2. t^p 2 - Chu Vin Bl£n t h u a n lOO Q mac noi tiep v o l t u dien c6 di#n d u n g 0,l/7i (mF). T i n h c u a n g Nguon mac tarn giac - T a i mac tarn giac do d o n g dien d i qua m o i tai. U = Ud=Ui. A. 4,4 A . B. 3 V2 A . C. 2 >/3 A . , D . 1,8 A . U S3 o:» \\:*ifKVi % I - ^ I - ^ I - Huang dan • ••„ gti1 .f: Z L =coL~233,24(Q);Z = J R 2 + Z ^ «380(Q) A. Iph= 1,5 A ; I.h = 0,2 A . ' B. Iph = 2,9 A ; I.h = 0 A . "^ = I2 = I3 = - = ^ 1(A) P = 3I?R = 9 0 0 ( W ) = 0 , 9 ( k W ) C. Iph = 5,5 A ; I.h = 0 A . D. Iph= 2,9 A ; I.i, =0,25 A '4 Huang dan A = Pt = 0,9.8.30 = 2 1 6 ( k W h ) V i tai d o i x u n g nen d o n g d i e n qua day t r u n g hoa bang 0. i , j ii/sq ^f, jj^w = > T i e n d i e n = 2 1 6 ( k W h ) x 8 5 0 = 183600(VND) ' ' T' ^•'=2,9(A) => Chon A. R R V i du 5: M o t may phat dien xoay chieu 3 pha k h i boat d o n g , n g u o i ta d i i n g =>ChonB. M'l..'v- '''V ^ , , von ke nhiet de do dien ap hai dau m o t cupn day t h i so chi ciia no la 127 V. V i d u 2: M o t may phat d i e n ba pha mac h i n h sao c6 d i e n ap hieu d u n g pha N g u o i ta d u a d o n g 3 pha do may phat ra vao 3 b o n g den g i o n g het nhau 127(V) va tan so 50 ( H z ) . N g u o i ta dua d o n g d i e n xoay chieu ba pha vao ba boat d o n g v o i d i e n ap hieu d u n g 220 V t h i cac den deu sang K m h t h u d n g . tai n h u nhau mac h i n h tam giac, m o i tai c6 dien t r a t h u a n 12Q va d o t u cam Chon p h u o n g an d u n g . , •/ • /v„-,,fi') - 51 ( m H ) . Xac d j n h tong cong suat ca ba tai tieu t h u . A. M a y mac h i n h sao, tai mac h i n h sao. ^ D.1452W. • A . 991 W . B. 3233 W . C. 4356 W . B. M a y mac h i n h sao, tai mac h i n h tam giac. t Huang dan ' C. M a v mac h i n h tam eiac, tai mac h i n h sao. Z L - ( 0 L = 16(fi): ' •' , , ., nil i-.hi Z - 7 R 2 + Z [ =20(Q) D. M a y mac h i n h tam giac, tai mac h i n h tam giac. _ , Huong dan P = 3I?R = 4356(W) ^ ^ Z Z N e u U = U P t h i de tai boat d o n g b i n h t h u o n g nguon mac sao - tai mac sao =>ChonC. • hoac n g u o n tam giac - tai mac tam giac. V i d u 3: M p t m a y phat dien ba pha mac h i n h sao phat d o n g xoay chieu c6 tan N e u U = V3 U P t h i de tai boat d o n g b i n h t h u o n g nguon mac sao - tai mac , so 50 H z , suat dien d g n g hieu d u n g m o i pha la 200N/2 V . Tai tieu t h u g o m ba doan mach g i o n g n h a u mac tam giac, m o i doan m a c h g o m d i ^ n tra 213
Neu U = U P / t h i de tai hoat d p n g b i n h t h u o n g n g u o n mac tarn giac - ta Huang dan mac sao. 22072Z^ 22072Z--2;? . • • 22072 — — 3 3 _33g =i. Chon B. V i du 6: (CD-2011) T r o n g m a y phat d i ^ n xoay chieu ba pha d a n g hoat dong Ith ='i"'^"'^=W7^" 20i ' -20i r^f^'^ .,1 ^ i(h = 3376 cosl007rt(A) => Chon C. suat dien d o n g xoay chieu xuat hien t r o n g m o i cuon day ciia stato c6 gia tri cue dai la Eo. K h i suat di?n d o n g tuc t h o i t r o n g m p t cuon day bang 0 thi ' 9= "^^y P^^* ^ ^'"'^ '^^ '^^^^ ^^^^ '^^^Z day suat d i e n d o n g tiic t h o i t r o n g m o i cuon day con lai c6 do Ion bang nhau va 220V, cac tai mac theo h i n h sao, 6 pha 1 va 2 c i m g mac m o t b o n g d e n c6 bang dien t r a 38Q, pha t h u 3 mac den 24Q, d o n g dien hieu d y n g t r o n g day t r u n g A . 0,5Eo V3 . B. 2Eo/3. C. 0,5Eo. D . a S E o V2 . hoa nhan gia t r j : •••vn.fi'i. ' K - ^ ^{"'••{••^ u-'-^'", ''v- '^.-f \ii vi. ;>,t liiln niri^iiift'MiCtfixt lif-irl -jtfi.: Huang dan •'"'^•^'b •; Chon A. Chu y: Neu nguon va tai deu mac hinh sao thi dong dien ti'tc thai qua day trung Uj U T , . \- ..,il>i ^ BAITOAN LIEN QUAN DEN DQNG CGf Dif N hoa: ith = i i + i 2 + i 3 = - = ^ + - ^ +^ (cong3 sophuc) Phuangphdpgidi V,, •^1 ^2 R V i du 7: M a y phat dien xoay chieu ba pha mac h i n h sao d u a van ba tai cung Hieu suat ciia d o n g co: ^ = ^ :iu'h HUV*I « K 1 ' I \. QU/2 coslOOTtt ( A ) , e2 = 220 V2 cos(1007t: + 2K/3) (A), ' A. 2,61.107 (J) va 3,06.10^ (J). B. 3,06.10^ (J) va 3,6.10^ (J). 63 = 220 V2 cos(1007tt - 2K/3) (A) va d u a vao ba tai theo d i i n g t i i u t u tren la " C . 3,06.10^ (J) va 2,61.10^ (J). D . 3,6.10^ (J) va 3,06.10^ (J). , d i f n t r o thuan R = 10/ N/3 Q , cuon cam thuan c6 cam khang Z L = 20 Q va tu Huattgdan d i e n CO d u n g k h a n g Zc = 20. Bo qua dien t r o cac cuon day ciia may phat, ciia day n o i va ciia day t r u n g hoa. D o n g dien chay qua day t r u i . g hoa c6 gia A = Pt = . ^ t = ^ ^ ^ ^ . 3 6 0 0 = 3,6.10^(J) • trj hieu d u n g la ? => Chon D. • A . 77 ( A ) . B. 33 76 ( A ) . C. 33 73 ( A ) . D . 99 ( A ) . 214 ,^ 215
v i d u 2: M o t d o n g ca dien xoay cliieii san ra mot cong stui't co hoc 10 k W va C. 3 c u o r day m a y phat mac theo h i n h sao, 3 cuon day cua d o n g co mac hicLi sua't 80% d i i o c mac vao mach xoay chieu. Xac d i n h dien ap hieu dui-,^ theo h i n h sao. 6 hai dau d o n g co bie'l d o n g dien co gia t r i hieu d u n g 100 ( A ) va tre pha D. 3 cuon day ciia m a y phat mac theo h i n h sao, 3 cuon day ciia d o n g co mac voi dien ap hai dau d o n g co la 7i/3. '' theo h i n h t a m giac. '/fx/'f:; ' 'i:: '/f.b n\ A. 3 3 1 V . B. 250 V. t v: C. 500 V . y'^'^'-' D . 5 6 5 V . ..rt u . u • ./ Huong dan ^A ,;, ^• Huong dan Theo so lieu U = 220 V, U P = 127 V tuc la U = Ui> . M u o n d o n g co hoat p = ^ = U I c o s ( p ^ U = — ^ • = 2 5 0 ( V ) ==>ChonB. , d o n g b i n h t h i r o n g t h i n g u o n mac sao - tai mac tam giac => C h o n D . H H I cos (p V i du 5: (CD-2010) M o t d o n g co k h o n g d o n g bo ba pha mac theo kieu h i n h V i d u 3: M o t d o n g co dien xoay chieu san ra mot cong sua't co hoc 8,5 k W va c6 sao d u g c noi vao mach dien ba pha co dien ap pha Ui'i^ = 220 '^L Cong sua't hieu sua't 88%. Xac d j n h dien ap hieu d u n g 6 hai dau d o n g co bie't dong dien ciia d o n g co la 6,6N/3 k W ; he so cong sua't cua d o n g co la 0,5^3 . dien CO gia t r i hieu d u n g 50 (A) va tre pha so v o i dien ap hai dau d o n g co C u o n g d o d o n g d i e n hieu d u n g qua m o i cuon day ciia d o n g co bang 7r/12. A. 20 A . B. 6 0 A . C. 105 A . v, D . 35 A. A . 3 3 1 V. B. 200 V. C.231 V. D.565 V. Huong dan HtiOfig dan N g u o n mac sao - tai mac sao nen U = UP: 8,5.i0'^ P 6,6^3.10^ p = I i = Ulcos(p: = 200(V) P = 3UIcos(p=>I- I = 2 0 ( A ) z:>ClionA. ,|, H H I COS (p 0,88.50 cos 3 U cos (p V3 3.220. =:>ChonB. • ' ^ ' • • V i du 6: M o t d o n g co k h o n g d o n g bo ba pha mac h i n h sao vao m a n g dien xoay Chu y: Khi miic dong ca 3 pha co dien ap dinh mux trcn moi tdi la U oao may pUdl chieu ba pha mac h i n h sao, co dien ap day 380 V. D o n g co co cong sua't 10 dien xoay chieu 3 pha c6 dien dp pha Id UP tin Hiy vao do Ian cua U jd Ui' md yen KW. H e so cong sua't 0,8. C u o n g do d o n g dien hieu d u n g d i qua m o i cuon can miic lunh sao liny mac hinli tarn gidc. day CO gia trj bao nhieu? * Neil U = Ih' vd dong ca hoat dg)ig hinh thwang th'i nguon mac sao - tdi mac sao A. 57,0 A . B. 18,99 A . C. 45,36 A . D. 10,96 A . , hoiic }iguon mac tam gidc - tdi miic tarn gidc. i:\:0'.'-:'.>- ^ c Huongdan ^''^ * Neil LI = Ui'yfs vd dgiig ca hogt dong Imh thirang tin nguon mac sao - tdi nm N g u o n mac sao - tai mac sao nen U = U P = U^l/^/3 : tarn ChonC. B. 3 cuon day ciia may phat mac theo h i n h tam giac, 3 cuon day cua dgnj? 3Ucos(p 3.220/3.0,85 CO mac theo h i n h tam giac. • ' 216 217
?o' trf> kien thitc V^t If LTPH tren Ttenh^PTV2. t^p 2 - Chu van BieiT / i d u 8: M o t d o n g ca k h o n g d o n g bo ba pha co dien ap d i n h m i i c m o i pha la Vao t h o i d i e m u = 3^2 A va dang tang nen co the chon cot = - - ( n a m 6 nua 380 V va he so cong suat bang 0,85. D i e n nang tieu thu ciia d o n g co t r o n g 4 mot ngay hoat d o n g la 232,56 k W h . C u o n g d o d o n g d i e n h i e u d u n g qua ducji V T L G ) . Thay gia trj nay vao bieu thcic 12 va is: . , 7t 271 moi cuon day ciia d o n g CO la ^: , •:m^_i^ I = 3V2 ( A ) Huong dan 2n P = Pj + l 2 r = > P = 5. + l2rr:>10'* = l ^ ^ + 1 0 2 r = > r = 10(Q) ^ChpnB. i i = 6 c o s ( c o t ) ( A ) ; i 2 = 6 c o s cot + • ( A ) ; i 3 = 6cos cot-- (A) 219
Bdtrgkic'n Ihitc Vfit ULTOlllrcn kcnh VI VJ, t ^ p ^ e - f ^ n u vanm e n cty TimnnrvpyvnKbang vt^t Chii y: Ncii doan mqch xony cliicu AB gain inach L R C pha voi I'M mot goc 30". Hieu dien the'a hai dau cuon cam la 125 V va som RLC run tiSp vai dorv^ ca dien 1 pha thi bleu thiic pha so voi dong dien la 60". Hi^u dien the hieu dung ciia mang di^n va do dien dp iren RLC, tren dgng ca Ian linrt la: lech pha cua no so voi dong dien Ian lugt la •;, „.:>;H n l o> U^B ^ 345(V) => Chon B. Cdch 1: U^B = U | + U ^ + 2URUcoscp /v 6 - Cdch 2: V i du 16: Mot dong co dien xoay chieu san ra cong suat co hoc 7,5 kW va co hieu suat 80%. Mac dong co noi tie'p voi mot cuon cam roi mac chung vho UAB = UR + U U^B = U | + U ^ + 2URUcosq) Un • 380^ - U ^ + 220^ + 2UR220.0,8 UR = 180,337 =^ R = ^ = 361(n) mang dien xoay chieu. Gia tri hieu dien the hieu dung o hai dau dong co 1'^ U M biet rang dong dien qua dong co co cuong do hieu dung I - 4 0 A va trf •Chon C. 220 221
Bd trfi klen thiic V$t li LTBll tren kenh VTV2. l.ip-J - Chu V^n Bl&n V i d u 18: T r o n g g i a hoc thuc hanh, hoc sinh mac no'i tiep m o t q u a t d i e n xoay 80 P ' = UIcos(p: .100 = U.0,5cos(p =0 U c o s 9 = 1 6 0 ( V ) chieu v o i d i e n t r o R = 352 Q roi mac hai d a u doan mach nay vao d i e n ap 100 xoay chieu c6 gia t r j hieu d u n g 380 V. Biet quat d i e n nay hoat d o n g 6 che'dg D i e n ap hieu d u n g tren R : U R = I R = 5 0 ( V ) d i n h m u c v o i d i e n ap d i n h m u c dat vao quat la 220 V v a k h i ay t h i d o lech T u p h u o n g t r i n h vec to: pha g i i i a d i e n ap a hai d a u quat v a c u o n g d o d o n g d i ^ n qua n o la cf), v o l U A B = U R + U chieu len true hoanh coscj) = 0,8. H a y xac d i n h cong suat d j n h m u c cua quat d i e n . va true t u n g ta duge: A. 90W. B. 2 6 6 W . t C. 80 W . D . 16CW. UABCOSCPAB = U R +Ucos(p '•'•• ••••V',-j:\'::i. Uuongdan •.>: (PAB = 10,93° = > U R = 1 1 4 , 2 3 = > R = ^ » 1 1 6 ( Q ) ' . I V;?;,. 120 ^ ' De quat hoat d o n g b i n h t h u a n g t h i R tang 116 - 100 = 16Q. U AB = U + U R = > U i s == + U R + 2 U U R cos (p V i d u 21: T r o n g m o t g i o thuc h a n h m o t hoe sinh m u o n m o t quat d i e n loai 180 , 9 , 1417 V - 220 W hoat d o n g b i n h t h u o n g d u o i m o t dien ap xoay chieu c6 gia t r i 33r - 220^ +120^ + 2.220.120.cos(p ^ c o s ( p = ^ ^ h i e u d u n g 220 V, nen mac no'i tiep v o i quat m o t bien t r o . Ban d a u hgc sinh d o de bien t r o c6 gia t r i 70 Q t h i do thay c u a n g do h i e u d u n g t r o n g mach la =^ P = UIcos(p = 2 2 0 . 2 . — = 389,675(W) => C h o n A . 0,75 A v a cong suat cua quat d i e n dat 92,8%. M u o n quat hoat d o n g b i n h V i d u 20: T r o n g m o t g i a thuc h a n h m o t hoc sinh m u o n m o t quat d i e n loai t h u a n g t h i p h a i d i e u c h i n h bien t r a n h u the nao? ^ 110 V - 100 W hoat d o n g b i n h t h u a n g d u o i m o t d i ^ n ap xoay chieu c6 gia A . G i a m d i 20 Q. B. Tang them 12 Q. »__p5l.»_^Bq^ t r i hieu d u n g 220 V , nen mac n o i tiep v o i quat m o t bien t r o . Ban d a u hoc C. G i a m d i 12 Q. D . Tang them 20 Q. ^ ^ sinh d o de bien t r o c6 gia t r j 100 Q t h i d o thay c u a n g d p h i e u d u n g trong Huang dan m a c h la 0,5 A va cong suat ciia quat dien dat 80%. L u c d a u , d o n g co hoat d o n g d u o i d j n h muc, cong suat tieu thia cua no: T i n h h§ so cong suat toan mach, he so cong suat cua 92,8 P ' = UIC0S(p: -.120 = U.0,75eos(p quat v a d i e n ap h i e u d u n g tren quat liic nay. M u o n ^• 100 quat hoat d o n g b i n h t h u o n g t h i phai dieu c h i n h bien A =t>Ueos(p = 1 4 8 , 4 8 ( V ) t r o n h u the nao? Biet d i e n ap g i i i a hai dau doan mach T u p h u o n g t r i n h v e c t o : U^g = Up, + U s o m pha h o n d o n g dien t r o n g mach. chieu len true h o a n h v atrue tung ta duge: ^' Humg dan UABCOSCPAB = U R +Ueos(p f220eos9AB =70.0,75 + 148,48 L i i c d a u , d p n g c a hoat d o n g d u a l d i n h muc, cong sua't tieu t h u cua no: U A B s i n (PAB = 0 + U s i n (p 1220 s i n CPAB = 0 + U s i n cp 223 999
So' tr(> kicn lltuc V^t li^LTDtlJrcn kcnh VTV2. t^p 2- CQ^ T/vmMTVDvvnKhang VIft =:>Usin 9 = 89,482 ket h o p v o i U cosip = 148,48 , suy ra: (p 0,5424 rad hay Huang dan cosq) = 0,8565. ' V • ' '^JKii • Pco Ulcoscp-Php 11 H = = 1 = 0,875 = 87,5% =>ChonD. * K h i d o n g co hoat d o n g b i n h t h i r o n g : D irjin „o».; : P UIcoscp 220.0,5.0,8 P = UIcoscp 120 = 180.1.0,8565 I = 0,7784(A) 0 d u 24: M o t d o n g co k h o n g d o n g bo ba pha tieu t h u cong sua't la 3,6 k W , Tir p h u o n g t r i n h vec to: U A B = U R + U chieu len true hoanh va true t u n g ta dien t r o t r o n g ciia m o i cuon la 2 Q va he so cong sua't la 0,8. D o n g co mac duoc: h i n h sao mSc vao m a n g dien mac h i n h sao v o i d i e n ap hieu d u n g 200 V t h i U A B COS(PAB = + Ucos(p 220coscpAB = U K +180.cos0,5424 ,' dong CO hoat d o n g b i n h t h u o n g . Coi nang l u o n g v 6 ich chi do toa nhiet U A B sincpAB = 0 + Usin(p 220sin(pAB = 0 + 180.sin0,5424 is:,,,,; trong cac cuon day ciia stato. H i e u sua't d o n g co la U, A. 92,5%. j,B.7,5%. C. 99,7%. D . 90,625%. ^ R = H i i - 58(n) ^ yAu ich va cong sua't tieu thy U2 N2 P, Ujli toan phan) la 4""' '6ng thuc m a y bien ap l i t u a n g ( H = 100%) va mach t h u cap co he so cong A. 8 0 % . B. 9 0 % . C 92,5%. D . 8 7 , 5 %. suatcos(p2: - 1 = _2.cos(p2 = — ^ . , 224
B d trp hidn th-ic V^t IILTDH tr&n k&nh VTV2. t4p 2 - Chu Van Bien Chti y: Nc'u nigt cuon day nao do (VD cuon sa cap) c6 n vong day quart nguvc thi tie Cong thuc m a y bieh ap h' t u o n g ( H = 100%) va t h u cap noi v o i R: truvng ciia n vong nay ngirgc vai tir truvng ci'ia phan con Iqi nSn no c6 tac duni^ khic bat tir truv'ng ciui n vong day con Iqi, lux la cuon day nay bi mat di 2n vong. U2 I, N2 Uj^^Nj—2n Or (-.-(.r n ' l i h i O - v a f e j s o i r M d m ; Jvv". fOf'? " :•• ,.• . V i d u 1: C u o n t h u cap cua mot may bieh ap c6 800 v o n g . TiJ" t h o n g trong bieh the bieh thien v o i tan so 50 H z va gia t r i t u t h o n g cue dai qua i-ngj V i d u 5: M o t may bieh ap l i t u o n g c6 cuon so cap g o m 100 v o n g day va cuon v o n g day bang 2,4 m W b . Ti'nh sua't dien d o n g hieu d u n g cuon t h u cap. t h u cap g o m 150 v o n g day. Mac hai dau cuon so cap vao m a n g dien xoay A . 220 V . ., B. 456,8 V . , C. 426,5 V . D . 140 V . chieu CO dien ap hieu d u n g 5 V. Neu 6 cuon so cap c6 10 v o n g day bj quah Humgdan n g u g c t h i dien ap hieu d u n g 0 hai dau cuon t h u cap k h i de h o la Ec, ^ 2nfNOo ^ 27t.50.8002,4.10-^ ^ 4 2 6 , 5 ( V ) C h o n C. A . 7,500 V. B. 9,375 V . '• C. 8,333 V . • D . 7,780 V . E = V2 V2 V2 Huang dan , ^ i-,:,,;' .';!S:,?1. j,, ......1.. : V i d u 2: (DH-2008) M o t may bieh ap c6 cuon so cap 1000 v o n g day d u o c mac C u o n so cap xem n h u mat d i 20 vong: (ilMi! f*i'-. vao m a n g dien xoay chieu co dien ap hieu d u n g 220 V . K h i do dien ap hiei, d u n g 6 hai dau cuon t h u cap de ho la 484 V . Bo qua m o i hao p h i cua may 7^ = —T; ^T^ = —7z =>U2 = 9 , 3 7 5 ( V ) =:>ChonB. , ' . . U2 N2 U2 150 ^ \ . (W» N2 = 2200 => Chon D . nhieu? • U2 N2 484 N2 A . 75. B. 60. ' ' C'm. ' D . 105. ''P^:' '''' Humgdan r i : U2 N2 U,U', Chu y: NcU tliay do] vai trd ciiu ak cuon day thi: => -1 Ui N] 220 1100 ^, ^ U', _N2 U,U', 77^ = r ^ — — - = > - ~ ^ =i>N2 =105 Chon D . U2 N2-2n 15 N2-3O ^ • V i d u 7: M o t m a y bieh ap v o i cuon so cap g o m 1000 v o n g d u g c mac vao mang ,. V i d u 3: D a t m o t dien ap xoay chieu u = 200coscot (V) vao hai dau cupn day so dien xoay chieu. C u o n t h u cap g o m 50 vong. Bo qua m g i hao p h i 6 may cap cua m o t m a y bieh the l i t u o n g t h i dien ap hieu d u n g do d u g c a hai dau bieh ap. C u o n t h u cap noi v o i dien t r a thuan t h i d o n g dien chay qua cuon cuon t h u cap la 10 V2 V . N e u dien ap xoay chieu u = 30cosail (V) vao h^n t h u cap la 1 ( A ) . H a y xac d i n h d o n g dien chay qua cuon so cap. dau cuon day t h u cap t h i dien ap do d u g c 6 hai dau cuon day so cap bang A . 0,05 A . B. 0,06 A . C. 0,07 A . D . 0,08 A . A.300V. B.2OOV2V. C.3OOV2V. D.I50V2V. Huangdau ' ; ''T ' Huaitg dan V i may bieh ap l i t u o n g va cuon thii cap noi v o i R nen ta ap d u n g cong UiU', IOO72.I5V2 =1 =1 U'2 = I50V2 ( V ) => C h o n D« U2U'2 ' ' 10^/2U'2 V i d u 4: M a c cuon t h u nhat cua m o t may bieh ap l i t u o n g vao mg^ nguoV. diC'^ => Chon A. ' " V xoay chieu t h i suat d i e n d g n g hieu d u n g trong cuon t h u hai la 20 V, Chu y: Nc'u cuon thu cap cm may bieh ap not vai RLC: v-v ioK cuon t h i i hai vao n g u o n dien xoay chieu do t h i suat dien d g n g h i ^ u d^-f' = U2 = : ^ -12 , • '•' t r o n g c u o n t h u nhat la 7,2 V . T i n h d i e n ap hieu d u n g cua n g u o n dien. U2 N2 ^R2+(Zi_-Zcf W M r.: M > A . 144 V . B.5,2V. C. 13,6 V . D.12V. j'' n Huang dan P, U,I, UiU'i . E.E =1 = 1 ^ E = 12(V) ^ C h o n D . U,U', 20.7,2 227
Ir^t hit^n I hut V^t l i Lmil l i c n hcnl, VTV2. t4ip 2 - Chu Van Blin c i y innn nrv own nitang vipr d\ 8: Cho m o t m a y bien ap c6 hieu suat 80%. C u o n so cap c6 100 vong, Huang dan N3 cuon t h u cap c6 200 v o n g . M a c h so cap l i t u o n g , dat vao hai d a u cuon so U3=Ui P,,=P„^UiIi=U2l2+U3l3- 200.il =10.0,5 + 200 ^ ^ . 1 , 2 cap d i e n ap xoay chieu c6 gia t r j hieu d u n g 100 V va tan so 50 H z . H a i dau 1000 cuon t h i i cap n o i v o i m o t cupn day c6 dien t r o 50 Q, d p t u ce,m 0,5/7t ( H ) . =:>Ii = 0 , 0 5 5 ( A ) = > C h o n C . ' C u o n g d p d o n g dien hieu d u n g mach so cap nhan gia t r i : V i d v 11: M o t m a y b i e n ap l y t u o n g , cupn so cap Ni = 1000 v o n g d u p e n o i vao A. 5 A. B. 10 A . C. 2 A . D . 2,5 A . dien ap hieu d u n g k h o n g d o i U i = 400 V . T h u cap g o m 2 c u p n N2 = 50 vong, Huang dan Na = 100 v o n g . GiCra 2 dau N2 dau v o i m o t d i e n t r o R = 40 Q, giua 2 d a u N 3 100 100 d a u v o i m o t d i e n t r o R' = 10 Q. Coi d o n g d i e n va d i e n ap l u o n c u n g pha. U2 =200(V)=^l2 = = 2^^(A) 200 C u o n g d p d o n g d i e n h i ^ u d u n g chay t r o n g cupn so cap la 8.50 A . 0,150 A . B. 0,450 A . C. 0,425 A . D . 0,015 A . •0,8 = •Ii=5(A) Chon A. 100.1 Huang dan ^ Uili i du 9: M o t may bien ap h' t u o n g c6 t i so v o n g day cua cupn so cap va t h u cap = 0,5 ( A ) U2 N2 U2 50 R 40 la 2. C u p n t h u cap n o i v o i tai tieu t h u c6 dien t r o 200 Q, c u p n S T cap n o i v o i 400 1000 U3 40 d i ^ n ap xoay chieu c6 gia t r j hieu d u n g 200 V. D o n g d i e n hieu d u n g qua U2=40(V)=>l3 = = 4(A) cupn SO cap la U,,, a,,, . M3 U3 100 R', 10 A . 0,25 A . , B. 0,6 A . C. 0,5 A . D . 0,8 A . ; UiIi=U2l2+U3l3 • 400.Ii = 20.0,5 + 40.4 => I i = 0 , 4 2 5 ( A ) Huong dan C h o n C. V i m a y bien ap l i t u o n g va cupn t h u cap n o i v o i R nen ta ap d u n g cong Chu y: Khi cho biei Ui, N1/N2, H va mach thu cap noi RLC, detinh Pi, Pz ta lam nhu thii'c: ' s-i • i IT N2 „ , U2 U 2 = — ^ . U i => I2 = --- ^ Ni ^ ^ U , = ^ . U i = lOO(V) => I2 = ^ = 0,5(A) + (ZL .1, sau: UiIi=U2l2+U3l3i suat toa nhiet tren tai tieu t h u la N3_ U3 A . 180 W . B. 90 W . C. 135 W . D . 26,7 W . „ Ni R' yini Huang dan / Kl- • , ^ „ - U2 I, N2 U II N; 1 ^ _L = i ! l t h i se dan den ket qua sai! 120 2 U2R Neu ap dung cong thuc —^ U i = -i- I2 = —^ Ni Ui I3 N. = - rr> U 2 = 1 8 0 ( V ) : ^ P2 = I 2 R = y = 135(W) U2 N2 R2+(ZL-ZC>' i du 10: M o t m a y bien ap ly t u o n g , cupn so cap c6 Ni = 1000 v o n g d u p e n o i =>ChonC. „ • • vao d i e n ap hi?u d u n g k h o n g d o i U i = 200 V. T h u cap g o m 2 d a u ra v o i so v o n g day Ian l u p t la N2 v o n g va Ns = 25 vong, d u p e n o i k i n t h i c u o n g d p V i du 13: Cho m o t m a y bien ap c6 hieu suat 90%. C u p n so cap c6 200 vong, hi?u d u n g Ian l u p t la 0,5 A va 1,2 A . D i e n ap hieu d u n g hai d a u cupn N2 la cupn t h u cap c6 400 v o n g . C u p n so cap no'i v o i d i ^ n ap xoay chieu c6 gia t r i 10 V. C o i d o n g d i e n va dien ap l u o n cung pha. C u o n g d p d o n g d i e n hieu hieu d u n g 150 V . H a i d a u cupn t h i i cap no'i v o i m o t cupn day c6 d i ^ n t r o d u n g chay t r o n g cupn so cap la hoat d o n g 90 Q va cam khang la 120 Q . Cong suat mach so cap la A . 150 W . B.360W. C.250W. ^ D. 400 W . A . 0,100 A . B. 0,045 A . C. 0,055 A . D . 0,150 A . 229
- Chu van B l i n Huong dan Huong dan P2 = P = 3 9 6 ( W ) U, __N, 150 _ 200 = 2,5=>U, =550(V) =>U2 =300(V) 396 U2 N2 220 U2 ~ 400 = 2,25(A) Ucoscp 220.0,8 P2 396 300^90 H = 0,9- I, =0,8(A) U2R 55OI1 =:>P, = I ^ R = = 360(W) U2 = U = 220(V) :4fl«±i:0i,(el;;ifc:; 90^+120^ ::::>ChonC. I'^iWi .i4hgn vi a f f m,>u:>'i;,,.: — ^ P , - 4 0 0 ( W ) r^ChonD.'', , , y l d u 16: M o t may ha ap l i t u o n g co t i so'giifa so'vong day cuon so cap va t h u cap la 2,5. N g u o i ta mac vao hai d a u cuon t h u ca'p m o t d o n g co 220V - rfiii 1/: Ne» m(ic/i thu cap ndi cdc bdni^ den (^fJ'' * P
V i d u 19: M o t m a y bien ap co l o i d o l x i i n g g o m bo'n n h a n h n h u n g chi co hai U2 N2 n h a n h d u o c quan hai cuon day. K h i mac m o t cupn day vao dien ap xoay chieu t h i cac d u a n g sue t u do no sinh ra k h o n g b i thoat ra ngoai va dupe chia deu cho hai n h a n h con lai. K h i mac cupn 1 (co 1000 v o n g ) vao dien ap V i dy 18: M a y bien ap t u ngau d i i n g cho cac tai c6 cong sua't n h o la m p t may hieu d u n g 60 V t h i 0 cupn 2 k h i de ho co dien ap hieu d u n g la 40 V . So'vong bien ap chi c6 m o t cupn day. Bien the t u ngau cuon ab g o m 1000 vong day ciia cupn 2 la q . , A-JJU ^ ,>u;!f ,1 . •j V o n g day t h i i 360 ke t i j a dugc no'i v o i cho't c. N g u a i ta no'i a, b v o i mgrig A . 2000 v o n g . B. 200 v o n g . C. 600 v o n g . D . 400 v o n g . d i e n xoay chieu 220 V - 50 H z (cupn ab luc nay g o i la cuon so cap) va noi be Huang dan v o i R = 10 Q (doan be liic nay gpi la cupn thiV cap). T i n h d o n g di?n d u a vao Uj •"60' • v , f K i i , n ti>g> n-1 Ni 4-1 1000 bien the. Bo qua m p i hao p h i t r o n g bien the. N2 = 2000 Chon A. U2 N2 40 N2 A . 9,6125 A . B.6,7A. C. 9,0112 A . D . 14,08 A . C/iM y: Nha lai trong trieang hop may bien dp hai cuon day khi hodn doi vai trb ta da Huang dan N i = Nab = 1000 N2=Nbc=N,b-N3,=640 ^ U2 N2 rut ra cong thitc: UjU'i =U2U'2 _N2 Cdch 1: U2 N 220 1000 =^U2 = 1 4 a 8 ( V ) U2 N2 U2 640 n-1 _U2l2gOS(P2 _ 140,8.14,08.1 1= Ii=9,0112(A) U2 Ui U'l PI Uili 22O.I1 Tuang tu vai bien dp co n loi thep: = U2U'2 n-l'n-1 > C h o n C. A> , n-l_N2 Ui__l2 _ Ni . 14,08 1000 Cdch 2: ^ = ^ = - •II =9,0112(A) U2 II ii N2 Ii 640 V i d u 20: M o t m a y b i e n ap co l o i d o i x i i n g g o m 5 n h a n h n h u n g chi co hai CM y: Binh thirang may bien dp c6 hai loi thep va cuon sa cap quan tren mot loi, n h a n h d u p e quan hai cupn day. K h i mac m o t cupn day vao dien ap xoay cuon thie cap quan tren loi con Iqi: = . j-, ...^ chieu t h i cac d u o n g sue t u do no sinh ra k h o n g bj thoat ra ngoai va dupe chia deu cho liai n h a n h con lai. K h i mac cupn 1 vao dien ap hieu d u n g 120 Neu may bien dp co n loi thep va cuon sa cap va thit cap dime quan 2 trong n loi V t h i 6 cupn 2 k h i de h a co dien ap hieu d u n g U2. K h i m i i c cupn 2 v o i dien , thi tit thong a cuon sa cap (p ditoc chia deu cho (n - 1) loi con lai. Tir thong qua ap hieu d u n g 3U2 t h i dien ap hieu d u n g a cupn 1 k h i de h o la - cuon thu cap Id ij^(n - 1) nen dien dp tren cuon thie cap gidm (n - 1) Ian. Ta co the A . 22,5 V . B. 60 V . C.30V. u D . 45 V . xem nhu dien dp tren cuon sa cap chia deu cho (n - 1) nhdnh va moi nhdnh cJu Huang dan l . . U 2 U 2 = . 4 ^ ^ . | ^ = U2U2 U'2 = 2 2 , 5 ( V ) = > C h o n A . ' nhdn duvc 1 phan: n-1 n-1 ' ^ 5-1 5-1 U2 N2 Chu y: Khi dp dung cac cong thiec tren tin dien tra cua cdc cuon day hhong ddng ke CM: Suat dien dong a cuon sa cap va thie cap Ian Iwat Id: va coi tie thong Id khep kin. Neii cuon thie cap deha con cuon sa cap co dien tra do thuan thi c6 the xem dien dp vao phdn bo tren tren R va tren cuon cam thuan ei = - N dt N (n-1) l(n-l): do e2 N2 N, L: U i = U R + U L = ^ U f =U^+Ut e2=-N2 R U (n-l)dt R J 232 233
Cty TNHH NTV D VVH Khang Vift Chi CO llidnli plum Ui.^^ih/ ra hicn tuang cam I'nig dien tiv ncn cd)ig thiec may bien y{ d u 23: Dat vao hai dau cuon so cap cua m o t may bien ap l i t u a n g (bo qua au luc nail la: —— = —- ,'• -- • : • - hao phi) m o t d i e n ap xoay chieu co gia trj hieu d u n g k h o n g d o i t h i d i e n ap ^ U2 N2 • • .K...: ' hieu d u n g giua hai dau cuon t h u cap de h o la 3 0 0 V . Ne'u g i a m b o t m o t Vi d u 2 1 : C u o n so cap cua m o t may bien ap l i tucVng cuon so cap c6 N i = 1100 phan ba t o n g so v o n g day cua cuon t h u cap t h i dien ap hieu d u n g giira hai .;!;'v6ng va cuon t h u cap c6 N2 = 2200 v o n g . D u n g day d a n co t o n g dien t r o R dau de ho cua no la de noi hai dau cuon so cap cua may bien ap v o i dien ap xoay chieu co gia t r i A. 100V. B. 2 0 0 V . C. 2 2 0 V . ,!/. ,D. IK.V. hieu d u n g on d i n h la U i = 82 V t h i k h i k h o n g noi tai d i e n ap hieu d u n g giua Huong dan UI i hai dau cuon thi'r cap la U2 = 160 V. T i so giOa d i ^ n t r o t h u i i n R va cam J r/i C f.'/l k h a n g Zi, ciia cuon so cap la • - (;.» liK;^ N, US 2N, ^ 3 .'UJ A. 0,19. B. 0,15. C. 0,42. D . 0,225. ' U, N, ' U^1 Ni 3 N Huoitgdan V i^'-i^i"' U' 2 UL _ N| UL 1100 ^it: • giua hai dau cuon t h u cap k h i de h o la A. 1 0 0 V. B. 2 0 0 V. C. 2 2 0 V . D. 110V. A. 80 V. B. 72 V. C.64V. D . 32 V. Huong dan V, H..„ Huong dan =•'^'^^-jij"^.' ^ 100 Nn 4 3 . . . qe raid \hts\i{M iQS. uh 4' Ta n h ^ n thay: dnl'o %j u, N, j u d l o M ( f I . O £ - F i G ) jYS jyb \J_ N, H -^^ n = N2 • Chon B. • C h o n C. U, N, 2U N2 - n N2-n UL _ Ni 32 1100 N, =>U2 = 6 4 ( V ) Ul U2 N2 U2 2200 N2+3n U' U' = 2. . = 2 . — = : > U ' = 200(V) Ul INN i ] INN, J Ul Ul Ni ''Vi d u 25: Dat vao hai dau cuon day so cap cua m o t m a y bien t h e ' l i t u o n g mot U2 N2 : I* d i e n ap xoay chieu co gia t r j hieu d u n g k h o n g d o i t h i d i e n ao hieu d u n g Khi may hicn ap co ao'vbng day a cum sa cap thay dcTi ta diing: u, N] ±n § giD-a hai d a u c u o n t h u cap de h o cua no la 100 V . Ne'u chi tang them n vong U'2 N2 day 6 cuon day so cap t h i dien ap hieu d u n g giira hai dau de h o cua cuon Ni -i t h u cap la U . Ne'u chi g i a m d i n v o n g day 6 cuon day so ca'p t h i d i e n ap hieu N2 d u n g giii-a hai d a u de h o ciia cuon t h u ca'p la 2 U . Ne'u chi tang t h e m 2n ^ Khi may bien dp co so vong day a cum thie cap thay doi ta diing: u. N2 ±n v o n g day 6 cuon so cap thi dien ap hieu d u n g g i i i a hai d a u cuon t h u cap de [U'l Ni h o la A.50V. B.60V. C.IOOV. D . 120 V. »34 235
Bo ttp klen thurc V$t li LTBH trgn kinh VTV2. t^p 2 - Chu Van Bien ~ C i y JTV/i/r nrv Dvvn'Knaag^vifsr' Huang dan BAI TOAN LIEN QUAN DEN TUYEN TAl DI|N phuang phdp gidi 100 N2 AP=I^R t'.i.mdi :;\rfij5 0';.*: (y\0*2i __ N i + n U " N2 N +n Ni =>2 = => n = —- ^ Chon B. Cuong do hieu dung chay tren duong day: I = U, N, U] _ N i - n Ni-n Ucoscp 2U Dp giam the tren duong day: N j +2n 5Ni U 1 _ 5 Ui PR PR ; U ' = 60(V) Thong thi/ilng xem cosy^l •>AU = U' N2 3N2 U ' 3100 A U = IR = Ucos(p u • V i dy 26: Khi dat mot dien ap xoay chieu c6 gia tri hieu dung khong doi vao cupn so cap thi di?n ap hi^u dung thu cap la 20 V. Neu tang so' vong day Cong suat hao phi tren duong day: AP = I^R = R.; thu cap 60 vong thi di^n ap hieu dung thu cap la 25 V. Neu giam so vong l^Ucoscp r: day thu cap 90 vong thi dien ap hieu dung thu cap la Dien nang hao phi tren duong day sau thoi gian t: AA = APt. A. lOV. B. 12,5 V. C. 17,5 V. D.15V. AP PR Phan tram hao phi: h = — Huang dan (Ucoscp)2 • \i \ 20 _ N2 Hieu suat truyen tai: H = 1 - h . Di?n tro tinh theo cong thuc: R = p - U, N, 25 N2 +60 4 N2 Ui Ni Ni Vi du 1 : Nguoi ta can truyen mot cong suat dien 200 kW t u nguon dien c6 dien U ' _ N 2 - 9 0 _ 240-90 _ 150 N2 U ' _ 150 20 ap 5000 V tren duong day c6 dien tro tong cong 20 Q va he so cong suat =:>U' = 12,5 bang 1. Do giam the tren duong day truyen tai la: U, Ni Ni 240 Nt Ul 240 U l A. 40 V. B. 400 V. C. 80 V. D. 800 V. ' ' => Chon B. ' ' ' Huang dan " ' V i du 27: (DH-2011) Mot hoc sinh quan mot may bien ap voi d u dinh so'vong 200.10-^ day ciia cuon so cap gap hai Ian so' vong day cua cuon thu cap. Do so suat f AU = I R = - -R = .20 = 800(V) =>ChonD. nen cuon thu cap bj thie'u mot so' vong day. Muo'n xac djnh so' vong day Ucos(p" 5000.1 thie'u de quan tie'p them vao cuon thu cap cho du, hoc sinh nay dat vao hai i u 2: Mot may phat dien xoay chieu c6 cong suat 1000 KW. Dong dien no dau cuon so cap mot dien ap xoay chieu c6 gia tri hieu dung khong doi, roi phat ra sau khi tang the'duoc truyen di xa bang mot day dan c6 tong chieu dung von ke'xac djnh ti so dien ap 6 cuon thu cap de ho va cuon so cap dai 200 km c6 duong kinh 0,39 cm va lam bang hgp k i m c6 dien tro suat Liic dau t i so' dien ap bang 0,43. Sau khi qua'n them vao cuon t h u cap bang 1,8.10'' (Qm). Biet he so cong suat duong day bang 1. Tinh cong suat < 24 vong day thi ti so dien ap bSng 0,45. Bo qua moi hao phi trong may bien hao phi tren duong day neu dien ap dua len la 50 kV. ' - •' ap. De dugc may bien ap dung nhu d u dinh, hoc sinh nay phai tie'p tuc A. 0,16MW. B.0,03MW. C. 0,2 MW. D. 0,12MW. ( quan them vao cuon thu cap Sfi'fcui i i; Huong dan i A. 40 vong day. B. 84 vong day. C. 100 vong day. D. 60 vong day. 200.10^ Dien tro duong day: R = p— = p — j = 1,8.10 -8 •*301(Q) I 1 Huang dan Tir 7i(0,195.10~^y •N2=0,43NI 1 jNi=1200 ., ,,.iyi: U, Cong suat hao phi tren duong day: N, = N1 i N2 + 24 = 0,45Ni J ^ |N2 = 516 A A2 Ul N2 + 24 + n = 0,5Ni => 516 + 24 + n = 0,5.1200 => n = 60 1000.10,3 AP = R = .301 * 0,12.10*^ (W) => Chon D . ' J'^ lit • => Chon D. U cos 9 ^ ^ 50.10^.1 j 236 237
Bo' t r p hien tltitc V^t l i L T O I I trcn kcnh VTV2. t a p J - LHU VJH BISH V i d u 3: 6 n o i phat n g u o i ta t r u y e n cong sua't t r u y e n tai dien nang la 1,2 MVV phat k h o n g d o i va he so'cong sua't trong cac t r u o n g h o p d e i . bSng nhau. d u o i dien ap 6 k V . Dien tro cua d u o n g day truyen tai t u noi phat den noi N e u dien ap t r u y e n d i la 4U thi tram phat nay cung cap d i i dier. nang cho tieu thu la 4,05 i l . He so cong suat cua doan mach 0,9. Gia dien lOOo A. 168 ho dan. B. 150 ho dan. C. 504 ho dan. D . 192 ho dan. , J dong/kWh t h i t r u n g b i n h t r o n g 30 ngay, so tien khau hao la Huong dan A . 144 trieu d o n g . ; B. 734,4 trieu d o n g . P - A P = 120P, .... ^tr C. 110,16 trieu d o n g . 1 ;, D . 152,55 trieu dong.,-,.,, AP = 32P, AP Huaiig dan P - _ = 144P, P = 152R Cach 1: Theo bai ra: • C h o n B. 4 ' C o n g suat hao p h i tren d u o n g day: 'V.f rciii •'•I'.i i . 17P P = nP, — nP, =152Pj - ^ = 150Pi ^ 1,2.K/^ ^ >1I 16 ' * * 16 AP = R = .4,05---200.10-'(W) AP = 32Pi. K h i U tang 4 Ian t h i phan A A = APt = 200 ( k W ) X 30 X 24 ( h ) = 144.10-^ ( k W h ) dien nang co ich tang them 15AP/16 = 30Pi, tire la d u cho 120 -H 30 = 150 ho dan. . •;; ' ' ' - Tien dien khau hao: 144.10'"* x 1000 = 144.10^' ( V N D ) =:> C h o n A . V i du 6: M o t d u o n g day c6 dien t r o tong cong 4 Q dan m o t d o n g dien xoay Chii y: Khi con^ suat dim Icn duvng day khmg doi, dien ap tang n Ian thi cong sufn chieu m o t pha tir n o i san xuat den n o i tieu d i i n g . D i e n ap liieu d u n g 6 hao phi giani nK n g u o n dien luc phat ra la 10 kV, cong sua't dien la 400 k W . He so cong sua't V i du 4: Bang m o t d u o n g day truyen tai, dien nang t u m o t nha may phat d i n i ciia mach dien la cosc|) = 0,8. Co bao nhieu p h a n tram cong sua't b i ma't mat nho ccS cong suat k h o n g d o i d u o c dua den mot x u o n g san xua't. N e u tai nha tren d u o n g day do toa nhiet? I o'"wn-li' may dien, d i m g m a y bien ap c6 t i so v o n g day cua cuon t h u cap va cuon so A. 1,6%. B. 2,5%. C. 6,4%. D . 10%. ) cap la 5 t h i tai n o i sir d u n g se cung cap d u dien nang cho 80 may hoat dong. Huong dan N e u d u n g may bien ap ccS t i so v o n g day cua cuon t h u cap va cuon so cap la AP PR 400.10^.4 10 t h i tai noi sir d u n g cung cap d i i diijn nang cho 95 may hoat d o n g . Neu AP - I^R = R=^h = - 0 , 0 2 5 = 2,5% ^ Ucoscp P U^cos> 10^0,64 dat x u o n g san xua't tai nha may dien thi cung cap d i i dien nang cho bao Chon B. nhieu may? V i du 7: T r u y e n tai m o t cong sua't dien 1 ( M W ) den n o i tieu t h u bang d u o n g A . 90. 'V -''B.IOO. C.85. D . 105. day 1 p h % dien ap hieu d u n g dua len d u o n g day 10 ( k V ) . M a c h tai dien c6 Huong dan he so cong sua't 0,8. M u o n cho ti le nang l u o n g mat mat tren d u o n g day G o i P, A P va P I Ian l u o t la cong suat nha may dien, cong sua't hao p h i trcn k h o n g qua 10% cong sua't t r u y e n thi dien t r o ciia d u o n g day phai c6 gia trj d u o n g day k h i chua d i m g may bien the'va cong sua't tieu t h u ^-iia m o i ma) thoa m a n -j^ f t , 6 x u o n g san xuat. , A. R