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H nh Cng n mn hc TB-T3 K48 _____________________________________________________________

LI M U

Trong cng cuc xy dng t nc i ln ch ngha x hi, vn cng nghip ho hin i ho t nc l nhim v c ng v nh nc ta t ln hng u. Trong nhim v pht trin ngnh cng nghip nng lng, sn xut v truyn ti in nng c c bit coi trng. Kh c in l thit b in dng iu khin, kim tra, t ng iu chnh, khng ch cc i tng in cng nh khng in v bo v chng trong trng hp s c.Kh c in c rt nhiu chng loi vi chc nng, nguyn l lm vic v kch c khc nhau, c dng rng ri trong mi lnh vc ca i sng.Vic tnh ton thit k cng tc t ni ring v kh c in ni chung l nhim v quan trng m bo cho ngnh cng nghip in nng ca t nc ta c th t ch trong vn sn xut cc thit b in phc v cho sn xut v truyn ti in nng m khng phi ph thuc vo vic nhp khu t nc ngoi.Di y em xin trnh by ton b ni dung n mn hc Thit k kh c in h p do thy gio Nguyn Vn c hng dn. Mc d trong thi gian qua em c gng ht sc tm hiu thc t, nghin cu ti liu thc hin n, nhng khng th trnh khi sai st, em mong tip tc nhn c s ng gp v ch bo ca cc thy. Em mong by t lng bit n ti s gip ca thy gio Nguyn Vn c, thy trc tip hng dnv ton b cc thy trong b mn Thit b in - in t dy d em trong nhiu nm va qua.

H Ni, ngy 10 thng 06 nm 2007Sinh vin

H nh Cng_____________________________________________________________ 1H nh Cng n mn hc TB-T3 K48 _____________________________________________________________

CHNG I. GII THIU V CNG TC TI. Gii thiu v cng tc t:1.nh ngha:Cng tc t l kh c in dng ng ct thng xuyn cc mch in ng lc, t xa,bng tay hay t ng.Vic ng ct cng tc t c tip imcthcthchinbngnamchmin, thulchaykh nn. Thng thng hay gp cng tc t ng ct bng nam chm in. Cng tc t in t gm hai loi, cng tc t ng ct bng nam chm in mt chiu v cng tc t ng ct bng nam chm in xoay chiu.2.Cu to chung:Cng tc t in t c cu to t nhng phn chnh: H thng mch vng dn in, h thng dp h quang, h thng cc l xo nh, l xo tip im, nam chm in, v v cc chi tit cch in.3.Nguyn l lm vic:a dng in vo cun dy nam chm in to ra t thng , t thng sinh ra lc in t khe h , do lc in t Fdt > Fphn lc l xo nn np nam chminyxung( )min , tipimng, cngtctng, mch thng.Ngt cng tc t: Ngt dng in cun dy nam chm in lm mt t thng ( ) 0 , lc in t Fdt = 0 nn l xo ko np nam chm in m, tip im m, hquang in c dp tt bung dp h quang,mchin ngt.II. Chn phng n thit k:1.Phn tch chn phng n thit k:Cng tc t in t xoay chiu dng nam chm in c hai dng:+MchthnhchUnphtquayquanhtr. Tipimkiungn, dng tip xc ng, dng dy ni mm a in vo tip im. Thch hp vi dng in ln, ch lm vic nng n ca cng tc t.+ Mch t hnh ch E np ht thng, mt phn phn ng ngp trong lng ng dy. Tip im kiu cu mt pha hai ch ngt, khng cn dy ni mm, dp h quang d hn, dng tip xc ca tip im l tip xc im hoc mt tu theo dng nh mc. Thch hp vi ch lm vic nh nhng ca cng tc t.Qua phn tch cc phng n thit k cng tc t trn kt hp vi yu cu thit c giao l thit k cng tc t in t xoay chiu c dng nh mc _____________________________________________________________ 2H nh Cng n mn hc TB-T3 K48 _____________________________________________________________

nh (30A) tn s thao tc 400ln/gi l ch lm vic nh nhng nn chn phng n thit k ti u l mch t hnh ch E np ht thng. 2.Phn tch chi tit phng n chn:*u im:+ Kt cu n gin.+ Lc ht in t c phn b u.+ Khng cn dy ni mm a in vo tip im ng.*Nhc im:+ Trng lng phn ng ln gy kh khn cho vic ht.+ Nu dng ln th m tip im ln dn n kch thc cng tc t ln.a)Dng mch t:Mch t hnh ch E, cun dy t gia, vng ngn mch t hai cc t bn, lc ht in t phn b u hn, c tnh lc ht in t st c tnh c m bo thit k ti u.b)H thng mch vng dn in:Tip im kiu cu mt pha hai ch ngt, u im l d dp h quang, khng cn dy ni mm a in vo tip im ng,do kt cu n gin. c)Bung dp h quang:Bungdphquangkiudndp, kchthcnh, hnchvngh quang chy, gim m thanh khi h quang chy.d)H thng phn lc:Dng l xo hnh tr chu nn, xon, phn lc nh ca tip im chnh, tip im ph u s dng phn lc l xo. Dngkt cu n ginCHNG II. TNH MCH VNG DN IN_____________________________________________________________ 3Vng ngn mchL xo nhcun dy nam chm intip imL xo tip imnp phn ngH nh Cng n mn hc TB-T3 K48 _____________________________________________________________

1.Tnh thanh dn ng:- Chn vt liu: Tra bng trang 44 v bng 2-22 trang 82, chn vt liu l ng ko ngui, k hiu: M1-TB+ T trng ():8,9(g/cm3).+ Nhit nng chy:10830C.+ in tr sut 200C

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20: 1,58.10) . (8m .+ dn nhit: 3,9 (W/cm. 0C).+ T trng nhit:0,39 (Ws/cm. 0C).+ cng Briven ( )BH: 80120(kg/mm).+ H s nhit in tr ( ) :0,0043(1/0C).- Thanh dn hnh ch nht: Theo cng thc 2.6 trang 19TLTK ta c: b= 32. ). 1 .( . 2. .od Tph dmK n nK I+ ;( ) [ ] 20 1 .20 + od od n=ba=412 ; Kph =(1,031,06) l h s tn hao ph do hiu ng gn v hiu ng mt ngoi, chn = 1,06.[ ] Cod0: tng nhit n nh, chn = 550C i vi ng.1]1

C01: h s nhit in tr.KT=(612)C0 2. mWh s to nhit iu kin khng khchuyn ng t nhin, chn = 7,5 ( tra bng 6-5 trang 300TLTK).( ) [ ] ( ) [ ] ( ) modC + + 8 8209510 . 09 , 2 20 95 0043 , 0 1 10 . 58 , 1 20 10 Chn n = 7.Kch thc thanh dn lm vic vi Idm = 30A:b = ). ( 76 , 055 . 5 , 7 ). 1 7 .( 7 . 206 , 1 . 10 . 09 , 2 . 3038 2mm +=> a = 7.b = 5,32(mm).Theo bng 2-15 trang 51TLTK: a = dtd + (12)mm. Vi Idm = 30A chn ng knh tip im d = 10mm (cao h = 1,8mm) nn tachn a = 12mm.Chn b = 1mm.Kch thc thanh dn ph lm vic vi Idm = 5A:b = 0,22(mm)._____________________________________________________________ 4H nh Cng n mn hc TB-T3 K48 _____________________________________________________________

=> a = 7.b = 1,54(mm).Theo bng 2-15TLTK: Idm = 5A => d = 3mm ( cao 1mm) => chna = 5mm, chn b = 0,3mm.2.Tnh kim nghim thanh dn:- Ch di hn:+ Mt dng in: J = ) / ( 4 2 ) / ( 5 , 21 . 1230.2 2mm A mm Ab aI => tho mn.+ Kim tra s pht nng thanh dn :tdtheo cng thc 2-4 trang 18TLTK:CK I K p SK p S K Iph dm TT ph dmod08 28 2020 02470043 , 0 . 06 , 1 . 10 . 45 , 1 . 30 5 , 7 ). 001 , 0 012 , 0 .( 2 ). 001 , 0 . 012 , 0 (40 . 5 , 7 ). 001 , 0 012 , 0 .( 2 ). 001 , 0 . 012 , 0 ( 06 , 1 . 10 . 45 , 1 . 30. . . . .. . . . . ++ ++ Trong : ( ) m ++8820010 . 45 , 120 . 0043 , 0 110 . 58 , 120 . 1 - Kimtra ch ngn mch:theo cng thc 6-21 trang 313TLTKnmnmtA Ajnm 0 tnh vi tnm = 3; 5; 10s.Vi iu kin nhit cho php ca ng l 950C.Nhit cho php i vi ng khi c dng ngn mch l 3000C.Theo hnh 6-6TLTK v tra bng 6-7 trang 305 TLTK ta c: . / . ( 10 . 75 , 3 ); S/mm . ( 10 . 4 , 1) 4 2 4 4 2 40mm S A A A Anm *Vi tnm=3s: ( ) [ ] ( )2 24 4/ 94 / 51 , 88310 . 4 , 1 10 . 75 , 3mm A j mm A jnm nm < => tho mn.*Vi tnm = 5s:( ) [ ] ( )2 2/ 82 / 56 , 68 mm A j mm A jnm nm < => tho mn.*Vi tnm = 10s:( ) [ ] ( )2 2/ 51 / 48 , 48 mm A j mm A jnm nm < => tho mn.Nhn xt: Da vo cc kt qu kim tra ch ngn hn v di hn ta thy cc thng s a, b u t yu cu k thut.3.u ni: Theo bng 2-9 trang 32TLTK:*Vi Idm = 30A chn vt M5 15 c ng knh ren d = 5mm_____________________________________________________________ 5H nh Cng n mn hc TB-T3 K48 _____________________________________________________________

+ Din tch tip xc ca u ni txdmbn dn txJIb a S .Jtx: mt dng ti ch tip xc.Jtx = 0,31A/mm2=> ( )277 , 9631 , 030mm Stx + Tnh lc Ftx ti ch tip xc:tx tx txS f F . vi ftx =( )2/ 150 120 cm KG : lc p tip xc n v.Chn ftx = 120 KG/cm2. Ftx = 120.96,77.102= 116,124(KG). + in tr tip xc phn u ni Rtx:( )mtxtttxFKR. 102 , 0 vi m: h s ph thuc hnh thc tip xc, chn tip xc mt, m=1.Ktt: h s tip xc, theo bng trang 59TLTK chn Ktt = 0,14.10( ) m 3( ) 63310 . 2 , 110 . 139 , 1 . 102 , 010 . 14 , 0txR+ in p ri ti ni tip xc:( ) [ ] mV U mV I R Utx dm tx tx30 2 036 , 0 30 . 10 . 2 , 1 .6 < Vy vic chn vt ni l thch hp.*Vi Idm = 5A, chn vt c ng knh ren d = 3 mm+ Din tch tip xc u ni Stx = 5/0,31= 16,1 mm2.+ Ftx = 120.16,1.102 = 19,35(KG).+ Rtx = 7,3.10( ) 6.+ in p tip xc: Utx = 7,3.106 .5 = 0,036mV < [Utx ] Vy vic chn vt ni l thch hp.4.Tip im:a)Vt liu lm tip im: Theo bng 2-13 trang 45TLTKvi Idm= 30A chn vt liu tip im l kim loi gm bc niken than ch:K hiu:KMK A32T trng( ) 8,7g/cm3 Nhit nng chy( )nc 1300 C0 in tr sut( )20 0,035.10( ) mm 3 dn nhit( ) 3,25W/cm. C0 cng Briven2/ 65 45 mm KG H s dn nhit in tr( ) 0,0035C01_____________________________________________________________ 6H nh Cng n mn hc TB-T3 K48 _____________________________________________________________

Vi Idm = 30A < 100A, chn tip im hnh tr cu: Tip im chnh: ng knh tip im d = 10mm, chiu cao h = 1,8mm. Tip im ph: ng knh tip im d = 3mm, chiu cao h = 1mm.b)Lc p tip im:*Da vo vic kho st in trng v nhit ca thanh dn ngi ta a cng thc 2-14 trang 52TLTKDng tip xc im: 2 221arccos1.. 16. ..1]1

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txtdBdm txTTH AI Fvi: Ttd :[ ] K0 nhit thanh dn pht nng di hn = 47+273 = 320 K0Ttx = Ttd + 8 K C0 0328 => ( ) KG Ftd035 , 0328320arccos1.25 , 3 . 1610 . 45 . . 10 . 3 , 2. 302 22 8211]1

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Tip xc im, n = 1: Ftd = n.Ftd1 Ftd = 0,035(KG).* Tnh Ftd theo cng thc thc nghim: dm td tdI f F . vitdf[G/A] l lc p tip im n v, tra bng 2-17 trang 55TLTKChntdf=10(G/A) => Ftd = 10.30 = 300(G) = 0,3(KG) = 0,3(N). Ftdc = Ftd = 0,3(KG).Ftdd = (0,40,7)FtdChn Ftdd = 0,6Ftd = 0,6.0,3 = 0,18(KG).* Tnh lc p ln tip im ph: Ftdc = 10.5 = 50(G) = 0,005(KG). Ftdd = 0,6.Ftdc = 0,003(KG).c)in tr tip xc Rtx:* Theo cng thc l thuyt 2-24TLTK ta c:( ) 33110 . 38 , 03 , 045 ..210 . 035 , 0 ..2tdBtxFHR * Theo cng thc thc nghim 2-25TLTK:( )mtdtxtxFKR. 102 , 0vi tip xc im: m = 0,5.Tra bng trang 59TLTK ta c Ktx = 0,16.10( ) N 3_____________________________________________________________ 7H nh Cng n mn hc TB-T3 K48 _____________________________________________________________

=> ( )( ) 35 , 0310 . 29 , 094 , 2 . 102 , 010 . 16 , 0txR=> Chn Rtx = 0,38.10( ) 3=> Utx = Rtx.Idm = 11,4(mV) < [Utx ] = 30mVd) Nhit tip xc: Theo cng thc 2-12TLTK ta c:( ) . . 8.. . .1. . .21. ..2220tx dmTtxtxtxR Is p KR Is p RI+ + + vi: : in tr sut ca vt liu tip im, =0,035.104 [ ] cm p,s: chu vi v din tch tip im (cm, cm2)KT: h s to nhit, = 7,5.10( ) C0 2 4. W/cm : h s dn nhit, = 3,25(W/cm. C0)C0040 : nhit mi trng.=> + + + 785 , 0 . 14 , 3 . 10 . 5 , 7 . 25 , 31. 10 . 29 , 0 . 30 .21785 , 0 . 14 , 3 . 1

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