- YJ =P2 =P1 LP= 1_LP =P
4 9: ang so qua nm
3.4.2.2. PhLI'O'ng phap hc1t di~n ap m6' may:
ChT dung v&i cac thi§t bi yeu c§u moment m6' may nh6.
a. Dung cu<')n khang baa hoa trong m?ch stator
Khi m6' may dong D 1, D2 m6': M6' may xong d6ng D2
-Luc m6' may tn,Pc ti§p:
Imm= Uam = Uam
✓R~ +x~ Zn
2 I
m1lmmr2 Mmm=----------'--
ro1
- Luc m6' may c6 cuon khang (di$n khang xk): Uam lmmk = -====== ✓R~ +(xn +xk)2 m1I2 r1 Mmmk = mmk2 TLI' d6, ta c6: lmmk /_R_2_+_x_2 = ,J n n =k<1 1mm ✓R~ +(xn +xk)2
Hinh 3.25 H? ap ma may bang ai~n khang
Theo phU'O'ng phap nay 1mm giam k Ian th1 Mmm giam k2 Ian. Phll'O'ng phap chi dU'Q'C dung trong cac trU'ang hqp ma van d§ trj s6 Mmm khong coy nghTa quan trong.
b. Dung bi~n ap tlf ngau h? Um& may
Khim& may dong 01 va 03, khi n = ndm dong D2, ngat D3. Goi:
- U1, I f la diE;}n ap va dong diE;}n cua ILI'&i.
- u~ m, I~ m: diE;}n ap tren Cl,J'C d(>ng CO' va dong diE;}n stator dong CO'. - Kr: la tT s6 bien ap (Kr< 1)
- Zn: la t6ng tr& mot pha.
Hinh 3.26 H? cJi~n ap m& may bang biJn ap fl!' ngau
NhU' vfj.y, khi m& may bang bien ap tl,l' ng§u dong diE;}n trong IU'&i giam di k2 Ian so v&i 1mm khi n6i trl,J'C tiep.
c. Phu1ang phap: Y - Ll
Chi SU' d1,mg v&i dong CO' co 2 cap 220/380 va lam viE;}c thU'O'ng trl,PC 6' cap Ca.ch m& may: Bong dao dBi n6i D2 v§ vi tri (Y). Bong 01. Khi n = ndm d6i 02 sang vi trf
GQi: UL: la diE;}n ap cua IU'&i.
UY: diE;}n ap pha khi day quan n6i Y, lmmLY, lmml.6.: dong diE;}n m& may IU'&i khi dau Y, t::,._
lmmf0Y, lmmf0.6.: dong diE;}n m& trong day quan stator khi n6i Y, t::,._ ·
Zn: t6ng tr& ngan rnc;tch mot pha.
YUJ
M /J m a y ,__ _ ___.
Hinh 3.27 Ma may bang phll'ang phap sao tam giac
* Khi dau Y: lmmLY =lmmf0Y = U y = ~
Zn ✓3.Zn
U.6. UL lmmf0.6. = - = - lmmf0.6. = - = - Zn Zn * Neu dong dong CO' vao IU'&i khi dau I::,.:
va r;:; ✓3.UL lmml.6. = -v"-'mmf0.6. = - - Zn lmmLY UL Zn 1 - - - = - ' - ' - - = 1m m L6. ✓3.Zn · ✓3.UL 3
Khoa fiien - Trtioflg TCN KTCN Huflg Voong
diE;}n 220V. ap m& may lam viE;}c. trong may pha Page 93
Dong di~n m& may trong ILI'&i khi n6i Y nho hO'n nhii§u khi n6i fl 3 Ian. Mmm c0ng giam di
2 2 UL
3 Ian: MmmY =Uy=
3
Trong khi Mmmfl = ui = ut. Coi phU'O'ng phap nay la trLI'&ng hQ'p d$c bi~t m& may bang bien ap tl)' ngau c6 kT = ✓3.