- YJ =P2 =P1 LP= 1_LP =P
n J Mc= Cost
Mc= Const no - f TN (Udm, <l>dm) _ Udm - no2 - - U1 - no3 - U2 - LJ3 -~ 0 M
Hinh 5.47. D~c tfnh ca cua c1{)ng ca c1i?n m{)t chi§u KT/I a nhiYng c1i?n ap khac nhau.
Ta c6 m(>t hQ d$c tf nh ca song song nhau va th§p d§n khi U giam d§n.
B. 89ng ca di$n mc)t chi~u kfch tll' n6i tiep (8C8MCKTNT):
a) PhLl'ang tr1nh d$c tf nh ca:
Trong 8C8MCKTNT ILi' = It= I cho nen khi Mc bien thien th1 ILi' bien thien, It bien thien (tll' tm&ng cua d(>ng ca, Cl> bien thien).
Theo d$c tf nh cua m9ch tll' th1 quan h$ Cl> = f(lt ) la tuyen tfnh khi m9ch tCP chU'a bao hoa. Trong d(>ng ca di$n kfch thfch n6i tiep khi Mc =0+(2+3).Mcctm th1 m9ch tCP cua chCmg lam
Vi$C tren 1 lo9t che dQ khac nhau tCP chLl'a bao hoa, bao hoa cho den bao hoa sau. Neu gia thiet mc;1ch tCP chLl'a bao hoa: Cl> ~ It, Cl> ~ kcplt, kcp =c18 trong vung I < 0,81dm· Dl)'a vao phU'ang tr1nh d$c tf nh t6c dQ d(>ng ca di$n 1 chi~u n6i chung th1 phLl'ang tr1nh d$c tf nh t6c de) cua 8C8KTNT c6 d9ng: n= U R Iv CE.kcp.lv CE.kcp.lv 8$t A= U · B= R th1: CE.kcp ' CE.kcp A n=--B Iv (6)
Mu6n c6 phU'ang tr1nh d$c tf nh ca chI
}. M M can thay: l v = - - = - - - - CMcI> CM .kcp .Iv TCP d6 ta c6: lu= ✓ M = ✓M CMCl> -JCMCl> The ILi' vao (1) va d$t
n
2
O Mcam
Hinh 5.48 ~ tinh CO' cua dQng CO'a~n
mÂt chiĐu kf ch thf ch noi tiep.
Ta c6 phU'ang tr1nh d$c tf nh ca: n= 1-B (7)
TCP (6) va (7) ta th§y d$c tfnh t6c dQ va d$c tf nh CO' cua 8C8MCKTNT c6 dc;tng hyperbol v&i di~u ki$n m9ch tCP chLl'a bao hoa.
Trong thl!C t§ cac 0C0MCKTNT dU'Q'C ch§ tc;lO lam vi$c v&i mc;tch tu bao hoa khi Mc > Mcdm· NghTa la khi Mc> Mcctm th1 d$c tinh CO' va d$c tinh toe do tuan theo qui lu~t hyperbol. Con khi Mc> Mcdm th1 Mc tang <I> h§u nhU' kh6ng d6i c6 doc;1n d$c tinh g§n nhU' dU'&ng thang.
AB: hyperbol BC: dU'&ng thang b) 0ieu chinh toe do:
a. 0ieu chinh toe do bang each thay d6i tu thong:
N§u dong di$n kich thich luc d§u la ILI'1 = lt1 th1 sau khi noi theo hinh 5.50a, b:
lt2 = k.lLI'1 v&i k la h$ so hi$u chinh:
I
k= · Rst (hinh 5.49a) K= W t <1 (hinh 5.49b)
~+R~ ~
Trong d6: w't so day qu§n kich thich sau khi noi theo b.
NhLI' v~y <1>2 = k.k<t>.11.11 nen <D 6 < <l>8ctm, n tang (d$c tinh CO' 2).
Tm&ng hQ'p c: mac nhLI' v~y th1 t6ng tr& giam, I = It tang, n giam lf'ng v&i dU'&ng d$c tinh
+ u + u - + u + u
Rsu
Hinh 5.49 Cac sa c16 cJifJu chinh t6c clQ cJ()ng ca cli?n m()t chifJu kf ch thf ch n6i
tiep: a) mac sun cha day quan kfch thfch; b) thay c16i s6 v6ng day cua day quan kfch thfch; c) mac sun cha phlin (mg; d) them cli?n tr& vaa mr;1ch ph§n (mg
CO' 3.
~- Them Rf vao m9ch ph§n lf'ng:
Luc m9ch tu bao hoa coi <1>0 = cte giong nhU' dong CO' di$n kich tu song song.
Luc m9ch tu khong bao hoa tu thong fi 1$ v&i ILI'. 0oi v&i h$ thong c6 quan tinh CO' du l&n, ta c6 th§ vi§t ph6ng chung phLI'O'ng
tr1nh s.d.d doi v&i th&i gian Dt ngay sau khi d$t them Rf va dU'&i d9ng:
U-Rlu n = - - - CE<l> C1E= CE<l> U= cl E.n/ Li+ 111.1(R0 +Rf) I I I C E.n.l u=CE.k<t>.I 1.1n. n 0 Mcam ,Rf =0 R
Khoa nieil _ Troorig TCN KTCN Hung Voong 1h 5.50 EJ?c trnh ca cua a¢ng w ai~n mÂt chiĐu kfch thfch n6i ti§p & cac frll'('mg
hQ'p aiĐu chinh t6c a khac nhau.
TL.I' d6 ta c6 dong di$n phan (mg sau khi d$t Rt la:
1\1 U
cl E.n +(Rf) +Rf)
Dong di$n phan (mg tm&c khi d$t bien tra:
u .
l u = - - - - c1E.n +Rf)
Ta l~p dU'Q'C tr s6:
Khi d$t di$n tra vao lam dong di$n phan C.rng giam, moment giam neu Mc = cte th1 Mdl = M0 - Mc< 0 lam t6c do quay giam, n SLl'C di$n dong giam, dong di$n phan (rng
tang den tri s6 ban dau va lam Vi$C 6n djnh a n2<ndm·
n1 = - - - - - - - ' - - ' - _ _ ; ; c ; _ _ _ _ _ _ ; ; _ U-lu(R0 +Rf) n 2 U-luRu
y. 0i§u chTnh t6c do bang thay d6i di$n ap:
0
2
4 M
ChT c6 th§ di§u chTnh dU'Q'C cac t6c do n < ndm· 0U'Q'C thl,l'c hi$n bang each d6i n6i song song thanh n6i tiep 2 dong ca. Hi$LI su§t cao kh6ng gay t6n hao ph1,1.
Hinh 5.51 f)~c tfnh CO' cua EJCEJDCKTHH so sanh v&i cac tor;ii EJCDDC khac
C. 0Qng ca di$n mot chi§u kich tCr h6n hqp (0C0MCKTHH):
0$c tf nh ca cua 0C0MCKTHH bu la d$c tf nh trung gian giCra d$c tf nh ca cua 0C0MCKTSS va 0C0MCKTNT.
T6c do cua 0C0MCKTHH dU'Q'C di§u chTnh nhU' 0C0MCKTSS ho$c 0C0MCKTNT.0ong ca di$n loc;1i nay thU'ang dU'Q'C SU' d1,1ng trong cac trU'ang hQ'p Mmm l&n, n bien thien trong 1 ph9m vi rong.
0$c tfnh CO' cua dong CO' di$n:
0U'ang 1 (rng v&i h6n hqp bu (n6i thu~n) 0U'ang 2: H6n hqp ngU'Q'C (n6i ngU'Q'C) 0U'ang 3: Kich thich song song
0U'ang 4: Kich thfch n6i tiep.
5.5.3.2 8$c tf nh lam Vi$C cua dong CO' di$n mot chi§u
M,n M = f(Iu) KTNT
n = f(Iu) KT//
_ _ n = f(Iu) KTHH n = f(Iu) KTNT
0 Iu'
Hinh 5.52 £)(le tfnh ca cua a{)ng ca ai~n m{)t chieu kfch thfch hon hqp so sanh v&i cac lof)i a{)ng ca ai~n m{)t chieu khac.
0$c tinh lam vi$c cua 0C0MC bi§u thi quan h$: n, M, ri theo dong di$n: n = f(ILI' ),
M = f(IU' ), Tj = f(IU') khi u = Udm = cte_
a. 0.:;ic tinh t6c d9: n = f(ILI') khi U = cte
n= u Ru lu
CE.<l>8 CE.<1>8
Ve can ban d.:;ic tinh t6c dQ n = f(ILI') tU'O'ng h,P nhLI' d$c tinh CO' da biet. b. 0.:;ic tinh momen M = f(ILI') khi U = cte_
Bi§u thi quan h$: M= CM <1>8.lu
6 d9ng cO' di$n kich thich song song: khi U = cte th1 <I> = cte quan h$ M = f(ILI') la dU'O'ng thang.
0 0C0MCKTNT: khi <I> ~ lu th1 M ~ 12udLI'O'ng cong c6 d9ng parabol.
6 0C0MCKTHH: 0U'cmg d.:;ic tinh moment la dLI'O'ng trung gian cua 0C0MC KTSS va
KTNT.
c. 0.:;ic t1nh hi$LI suat h = f(ILI') khi U = cte,lt = cte TU' cong thLI'c:
ri¾ = (1-2)]100 = [1- LP J100 = [1- PO + Pcu.t + 12uRu + Ptx + Pf ]1 OOTrong d6:
P1 U(lu +It) U(lu +It)
PO t6n hao khong tai (t6n hao CO' PcQ', t6n hao thep PFe, t6n hao phl) Pf).
Pt= Lit It t6n hao tren m9ch kich tll'. 12u .Ru t6n hao d6ng tren day quan ph§n LI'ng.