NGHIEN CUfU-TRAO D6I NGHIEN CLPU M N VA TU6l THO COA CAP MA SAT CO GOP C H | THAN DONG CO DIEN DC WEAR AND LIFE STUDY OF THE FRICTION PAIR OF DC MOTOR COLLECTORS AND CARBON BRUSHES Nguyin Van Doan', PGS,TS Pham Van HiingS TS Nguyin Th| Ngoc Huyln^ 'Trudng Dai hgc Sao D6 -Truong Dai hpc Bach Khoa Ha Noi Bdi bdo ndy trinh bdy ket qud nghien euu, tong hpp ve qud trinh mon, chi nguyen nhan cda cdc dgng hu hong ve mon vd to chirc nghien cim thi^c nghiem ve mon choi than - co gop Kit qud thirc nghiem vi mon se xdc dinh duac tuoi thp dukiin cua cdc loai choi than thi nghiem, tit CO ke hoach bdo duong sua chiia phuc hoi co gop phii hpp T u khoa: Qud trinh mon ma sdt, choi than vd co gop ABSTRACT The paper presents the results from studying, aggregate the wear process, indicates the cause of wear — in failure types and organization experimental study on carbon brush and collector wear These results help us to forecast life of the experimental carbon brush classification, therefore we can plan collector maintenance, repair and recovery appropriately Keywords: The wear process, friction, carbon brushes and collectors ISSN 0866 - 7056 TAP CHl CO KHf VIET NAM, S6 ndm 2015 www.cokhivietnam.vn "^ NGHIEN CUfU-TRAOOOI l.DATVANDE Trong dpng ca dien DC, cap ma sdt choi than & c6 gdp la mot nhiing bp phdn cau thdnh quan trgng quyet dinh tuoi thp vd tin COT ciia dpng CO Viec nghien ciiu, xac dinh dugc tuoi thp du kien ciia cap choi than & cd gdp vd c) Trupt be mat dua kl hoach thay the choi than, bdo dudng sira chiia phuc hdi co gop la thv:c su can thiet Bdi bdo ndy trinh bdy ket qua nghien ciiu thuc Nguyen nhan: Do tang dien dp qua nghiem va tinh toan tuoi thp du kien cua cd gdp - trinh chuyen mach lam dot chay phdn doan mat choi than dieu kien phdng thi nghiem KSt tiep xiic trugt qud nghiSn cim ed the Id tdi lieu ky thuat tham khao cho viec sua chiia, thay the co gdp, choi than dong ca diSn DC thvtc te su dung Wsm^ ' CAC DANG HU* H O N G BE M ^ T C H O I THAN [8] Tr€n hinh 1, trinh bay cdc hu hdng chii y6u cua choi than vd nguyen nhan gdy cac hu hongc d) Be mat tdch doi Nguyen nhdn: Do choi than doi bj nghieng qua trinh hoat dpng a) Be mgt bi chdy cgnh vd hong Nguyen nhan: Do tiip xuc khdng dam bao, phat m tia lua dien qua trinh ma sat e) Bi mgt bi ton thuong sdu Nguyen nhan: Do dich chuyln cac phdn ^ ^^^^ ^irt tir cd gop f) Be mat bi va canh b) Be mat bi xoi mon XT , ^^ , , , Nguyen nhan: Hu hong tia lua dien, dong dien qua tai, trayen tai dong dien bi gian doan lien tuc tao cac vSt rS, sin sm tren b6 mjt Nguyen nhan: Do 1dm viec qua tai ve dong dien, ap luc va t6c = ôã Hinh Cdc dang hu hong chu yiu cua chdt than w nghiin nhdn gdy hu hdng ISSN 0866-7056 TAP CHl CO KHI VlfiT NAM, S6 nam 2015 www.cokhivietnam.vn NGHIEN CUfU - TRAO DOI CAC DA.NG HU" HONG BE MAT CO GOP [6] ^ Tren hinh 2, trinh bay cac dang hu hong chu yeu cua cd gop va nguy6n nhan gay cac hu hong a) Vet chay mep sau: La su xoi mon cua mep sau cua cac phien gop Do cac linh kien may bi hong hoac doi xiing dien lip khong, c6 thi din d6n hu hong nghiem trpng d6i voi c6 gop d) Tao vit rang: La qua trinh x6i mdn cdc phien gop CO g6p Gay tac dpng cd chu ky cua CO hoac dien; Khong cdn bang, true lech, true uon cong, vong bi kem, nen mong yeu, bd can bdng hoac kit noi kem Ket qua Id xay tinh trang phdng dien be mat e) Tgo ranh: La su mai mdn deu theo chu vi, bang he rpng ciia choi than Nguyen nhdn la: Bui mdi mdn qua miic khdng hoac choi b) Vet chdy ranh khia: Ld sy: xoi mdn cua mdi than bi mdi mon; Ap suat ciia 16 xo qua thap g6p thu: hai, thii ba ho$c thii tu tiiy thupc (dudi 1.5pst); Lap dat choi dien khdng phu hgp vdo thiet ke cua phan iing Do vat lieu cua choi vd lpc khong kem than khdng phu hgp, thiet ke ch6i than hoac b6 di§u chinh dien ciia mdy f) Keo ddng: Xdy cd gdp trang thdi nhiet dp cao Do cdc hat dugc hao boc bdi cdc chdt nhilm tu moi truong xung quanh; Hoac c) Cao xu&c: Ld su phd buy be mat cua cd gdp qua trinh xii ly choi than va dxy hda khdng dung bdi cdc hat ddng bam vao bl mat chdi than Viec de tao cdc mang mdng tren be mat ciia ed chuyln rdi cac hat ddng dp lire 16 xo thdp, tdi g6p Viec cdc hat tich tu tai cac canh ciia phien trpng nhe hoac nhilm ban, gay m6n bat mai g6p, co thi gdy hien tugng chap mach tren c6 gdp Kit qua la giam cdng sudt cua bp cd gdp mica each dien Ket qua cd the gdy hu hong vd tu6i thp ciia chdi than nghiem trpng Hinh 2: Cdc dgng hu hdng chd yeu cua co gop vd nguyen nhdn gdy hu hong ISSN 0866-7056 TAP CHI CO KHi VIET NAM, S6 nam 2015 www.cokhivietnam.vn ^ NGHIEN ClJfU-TRAO 061 Sau m$t thai gian boat ddng, cd gdp cua dpng CO hi mdn, bl mat bi cao xudc, Lam xudt hien mpt sd hu hdng rjiu da trinh bay hinh 2, nlu idiong dugc bdo duong, thay thi c6 thi anh hudng tdi boat dpng ciia dgng co nhu: Dong CO cd tiing dn ldn, rung Idc manh, xudt hien nhilu tia lira di^n, cong suat yeu lugng chdi than Hi?u khii lugng chii than liics ban ddu va khdi lugng chdi than cdn dugc tuang ling tiing khodng thai giai t,, t^, t^, t^, la lugng m6n can xdc dinh AG (g) eua chdi than Ap dung cdng thiic tinh cuang dp m6n cua c6 gop vd lugng m6n co gdp TRINH Tir THI NGHIEM DO M N CO THIET BI DO MON CAP MA SAT CHOI GOP VA CHOI THAN [3] THAN VA CO GOP BK -MCG 5.1 Xac dinh thong so ban dau Thirc nghiem mdn chdi than va co gdp - Thilt bi mon BK-MCG dugc noi vdi dugc tiln hdnh tren thilt bi mdn BK-MCG dgng CO khon^ dong bp ba pha cd cdng suit N Sa d6 nguyen ly cdu tao thiet hi mdn dugc th6 = 0,27 KW, sd v6ng quay n = 1400 (vdng/phiit) hien tren hinh bang khdp cac dang So cap chdi than vd c6 gop dugc thi nghiem dong thdi Id cap - Hmh dang, kich thudc cd gdp hudc thirc nghiem: D = 36,5 (mm), sd lugng phien gdp: 30, dugc the hipn c\i the tren hinh V \u ikVsL^ 1) Bong ca; 2) Noi tntc, 3) Goi dS, 4) Trvc; 5) Vit; 6) Gia choi tlian; 7) C6 gop: 8) VU tri: 9) Day ndi; 10) Dai 6c cong; 11) bi; 12) Di; 13) Chdi than; 14) Bu long chong xaay; IS) Bgc 16) Bu long Hinh 3: Cdu tgo thiet bi mon BK - MCG Nguyen ly boat dpng cua thilt hi BKMCG: Chuyen d^ng quay cua dpng ca truyen cho true cua thiet bi thdng qua true cac ddng Treii true cd Idp cd gdp, cac chdi than 13 dugc Idp tren gia da chii 6, giii chat bdng cac vit 8, cac chdi than ludn ti sdt vao co gdp nhd 16 xo nen cila chdi than Hai I bi 11 giiip cdc chii than va gid dd chdi than c6 the chuySn dpng quay dgc lap so vdi true co ga cd gop Khi true quay nhd co hai bi 11 va bulong chdng xoay 14 nen gia chdi than se khdng bi quay theo (ket cdu iiay dugc sir dung mo men ma sat cua cl gdp - Chdi tiian) Chdi than ludn ti vao cd gop nen true quay thi giiia chii than va cd gdp cd su trugt tuong dii vai ddn din xudt hien Igc ma sat Ma sat chdi than va cl gdp ddn den su mdi mdn cho cd chii than va c6 g6p Sau thai gian thi nghiem t, = 5h, t, - lOh, tj ^ 15h, t^ = 20b tiln hdnh dimg thilt bi khdi Hinh 4: Hinh ddng, kich thudc cua co gop trudc k thuc nghiem Su dung loai chdi than thong dung cd hinh ddng nhu tren hinh va cd khdi lugng nhu sau: - Cap sd 1: KhIi lugng ban ddu G.j ^^ = 7,9285 (g); - Cap s6 2: KhIi lugng ban ddu G^^= 7,9230 (g); - Cap so 3: Khdi lugng ban ddu G.j.(^ = 8,1465 (g); - Cap s6 4: KhIi lugng ban dau Gj.^ = 7,0886 (g); Hinh 5: Hinh ddng, kich thuac cua 04 loai chdi ISSN 0866 - 7056 TAP CHf CO KHi VlfiT NAM, Sd nam 2015 www.cokhivietnam.vn than truac thuc nghiem «' NGHIEN CtfU - TRAO OOl 5.2 Xac dinh lirorng mon ciia ch6i than va co Xac dinh dugc cuong dp mon cua co gop bang g6port = Sh,t = 10h,t = 15h,t = 20h cong thiic: A Sau kiem tra tit ca cac di6u kien, tifa hanh chay thiSt bi mon BK-MCG Sau thai gian t, = 5h thu nghiem, khoi lugng chdi than va kich fliuac co gop se giam di so voi ban d4u Tit xac dinh lugng mon cua ch6i than: AGCT = GTCT-GscT(g) (1) IhCG = —^ CIM Ih CT [1] A (^) Trong do: °" (1 + c 2"*"';? = _ ®2 0, - Hang s6 modun dan hoi cua vat lieu Trong do: ^ i , choi than: 0, ^ u.f (^: Khoi luong choi than truac thi Ej ^^• ^^'' 0j - H5ng s6 modun dan hoi cua vat lieu : Khoi lugng choi than sau thi nghiem (g) c6 gop: 0j Tu ket qua mon a tren xac dinh cuong mon Ih CT cua choi than theo cong thiic: Lap lai trinh tu thi nghiem cho cac khoang thoi gian t^ = lOh, tj = 15h, t^ = 20h, ta I^CT= D/D • DGc/(-^.-L) [1] (2) CO bang kjt qua thi nghiem nhu bang Bdng Tong hop liet qud luang mon ciia timg cap choi than sau cdc thuc nghiem Chi d6 thi nghiem t=5h t=10h t=15h t = 20h C^p so 0,0292 0,0419 0,0549 0,0688 Luong mon sau moi lan thu (g) Cap so Cap so 0,0207 0,0201 0,0225 0,0338 0,0265 0,0476 0,0321 0,0621 C^p so 0,0683 0,1026 0,1347 0,1731 5.3 Xdy dung dudng cong mon thirc nghiem va tinh tuoi tho cua cap ma sat Tii kit qua thuc nghiem dugc tai bang 1, xdy dung dugc thi lugng mdn ciia timg cap chdi than phg thupc vao thdi gian hoac quang dudng ma sdt ISSN 0866 - 7056 TAP CHf CO KHI VlfiT NAM, S6 ndm 2015 www.cokhivietnam.vn NGHIEN CUfU - TRAO oCl Ufgi t(h) Hinh 6: Bd thi thuc nghiim quan hi cua luang mdn U theo thai gian cda cap chdi than 5.4 Tinh cu&ng d? mdn cua Co gop [1] Theo ly thuylt ca phdn tii Kragelsky xdc dinh dugc cudng dp mdn cua c6 g6p theo cong thiic 3: IhCG = —^ ttM Ifa CT Vdi: |j.p JJ.J - he sl Poatxong cua choi than vd c6 gdp: [ij = 0,3; ji^ = 0,33 E j , Ej - He sd modun dan hdi cua chii than va cd gdp: E, = 260 GPa; E^ = 125 GPa tf=6J; B = - ^ - l / ; ^ = , L 2v+I Thay sd vao cd: a,^ = 1,15 10^ Sau tinh toan c6 dugc bang tdng hgp cudmg dp mdn cua Cd gdp nhu bdng Bdng Bdng tdng hap cudng mon cua cd gdp theo thai gian Che thi nghiem t = 5h t=10h t=15h t = 20h Co gop so 39,53 28,36 24,77 23,29 Cuong d§ mon I,, ^^ (10"") Co gop so C^ gop s6 27,21 28,03 22,87 15,23 11,96 21,48 10,87 21,02 ISSN 0866 - 7056 TAP CHi CO KHi VlfiT NAM, Sd nam 2015 www.cokhivietnam.vn Co gop so 92,46 69,45 60,58 58,58 •L '' NGHIEN CUfU-TRAOedi 5.5 Xac dinh tu6i thp cia chfii than tren cff so mon thuc nghiem Lugng mon U ciia choi than va co gop dugc xac djnh theo cong thiic: h- U [1] Trong do: (4) U = Ih.L \- Cuong mon khong thii nguyen L - Quang duong ma sat Quang duong ma sat ttong thuc nghiem dugc xac dinh theo cong thiic: L = v.t Trong do: (5) v - Van toe cua c6 gop (m/ph); v ^ ; I-Thoi gian (phut); ^"""' d - Duong kinh cua co gop: d ^ 36,5 mm; n - So vong quay cua co gop: n = 1400 v/ph Ket qua tinh toan lugng mon U ciia choi than theo chieu cao lop mon dugc the hien Bdng Luang mon ciia choi than theo chieu cao lap mon Che 1$ thi nghiem t = 5h t=10h t=!5h t = 20h Lirgng mon ciia choi than U (^m) Cufrng mon \ ^ (10^) Cap so Cap so Cap so Cap so Cap so Cap so Cap s6 Cap so 34,37 24,66 21,54 20,25 24,37 19,89 18,68 18,28 23,66 13,24 10,40 9,45 80,40 60,39 52,68 50,94 16,54 23,74 31,11 38,99 11,73 19,15 26,98 35,20 11,39 12,75 15,02 18,20 38,7 58,14 76,07 98,08 De tinh mdi tho ciia choi than lay lugng mdn cho phep cua chdi than \S^^ ^ 10000 p.m, theo so lieu ciia nha san xuat - Xdc dinh lugng mdn trung binh cua choi than m6i khoang thdi gian 5h thuc nghiem: (6) u„ = ii:y, Tir ket qua cua bang ta xac dinh dugc gia tri ciia cho cap ch6i than s6 la U^, = 9,75 (nm) '^ ISSN 0866 - 7056 TAP CHi CO KHl VIET NAM, S6 nam 2015 www.cokhivietnam.vn NGHIEN CUfU-TRAOOCl - Tdc dp m6n trung binh theo thdi gian y^,: Trong m6i khoang thai gian 5h thuc nghiem, co U^j = 9,75 (pm) nen y^, = \Jjt = 1,95 (^im/h) Vdy tuli thp trung binh cua cap chdi than sd Id: T =[U nij ]/y^ = 5.130 h max * Tuang tu, tuli tho trung binh cua cap choi than sd la: T^ =[U^J/y^-5.682 h * Tudi thp ttnng binh cua cap choi than sd la: T^ = [ U ^ J / Y ^ - 9 h * Tudi thp trung binh cua cap chdi than so Id: T^ = [U^J/ Y^, - 2.039 h 5.6 Xac dinh tuli tho cua co gdp tren ca sd mon thu-c nghiem Tir thuc nghiem xdc dinh dugc cuang dp mdn khdng thir nguyen cua cd gdp, de xac dinh lugng mon U cua co gdp theo chieu cao lap mon dp dung cdng thiic Kit qua tinh todn dugc the hien bang Bdng Lupng mdn cua co gop theo chieu cao lap mon Che dp thi nghifm t=5h t=10h t=15h t = 20h Cuongaa mdn I„^, ( " ) Lirong mon ciia ch6i than U (^m) Cap so Cap so Cap so Cap so Cap so Cap so Cap so Cgp so 39,53 28,36 24,77 23,29 28,03 22,87 21,48 21,02 27,21 15,23 11,96 10,87 92,46 69,45 60,58 58,58 0,190 0,273 0,358 0,448 0,135 0,220 0,310 0,405 0,131 0,147 0,173 0,209 0,445 0,667 0,875 1,128 De tinh tuoi thp co g6p Idy lugng mon cho phep cua co gdp [U ] = 1000 |im, theo so lieu cua nha san xudt - Xac dinh lugng mdn trung binh cua cd gop moi khoang thai gian 5h thuc nghiem theo cdng thiic sl (6) va bang dugc gia tri cua cho c6 g6p sl la U^, - 0,112 (pm) ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd nam 2015 www cokh ivietnam.vn NGHIEN CUfU-TRAODOI _ " ^^c dp m6n trung binh theo thai gian y ^ Trong mdi khoang thdi gian 5h thuc nghiem, c6 ^rni - 0,112 (^m) nen y_^, - U_^/t -0,0224 (^im^) Vay tuoi thp trung bmh cua co g6p sd la; "^mi^rUrnJ^Y^i^ 44.643 h Tucmg tu, tudi thp tmng binh cua cl g6p sl la: T ^ - [ U ^ J / y ^ = 49.383 h Tudi thptiimgbkih ciia cl g6p sd la: T„^-[U_]/y^ = 95.694 h * Tudi thp trung bmh cua cd g6p sd la: "^0,4^ tUn^Vr^^^ 17.730 h '._ -^ KET LUAN - Qua cdc ket qua thuc nghiem cho thdy, mdi tho cua cd g6p dai hon tudi tho cua chdi than gan lan, dieu hoan todn phu hop vdi thuc te vat Ueu lam cd gop ciing ban nhieu ldn so vdi vat heu lam chdi than Vi vay, co gdp cd tic dp mdn nhd han nhieu so vdi ehdi than la phu hgp vdi ly thuyet - Tir ket qua thuc nghiem da tinh dugc cudng dp mon ciia cac loai chdi tha.n thdng dung tren thi trudng (nam khoang tu 9,45.10-'-6 den 80,4.10-6) va xac dinh dugc tudi thp du kien cua cdc cap ma sat chdi than c6 gop cua dpng ca dien DC cac dieu kien tuong tu nhu thuc nghiem -Tudi thp du kien ciia loai chdi than va cd gdp co su khdc biet ro rang, dieu the hien chat lugng cua vat lieu va cdng nghe che tao chua ddng deu.