- YJ =P2 =P1 LP= 1_LP =P
42. Dqng C0'3 pha lam vi~ 6' h.roi cr~n mQt pha (m~ch Steinmen1z)
Uip rap do va ti~n hanh thi nghi~m:
De tien hanh phep do can tien hanh cac dt,tng ct,t sau: Thiet bi: - Cong tac bao V$ Fl v&i day noi nguon
- Bien ap ba pha c6 nhieu day ra - Phanh ham dieu khien
004.035 004.024a 004.010 - Dong ho do toed(> 0 .. .4000 vong/phut 004.015a
- Volt ke 0 ... 250 V 004.012
- Ampere ke 0 ... 2,5/7,5 A 004.013a
-Watt ke m(>t pha 004.022e
D¢ng ca rotor long s6c ba pha khong dong bQ 004.003
- Tt,t lam Vi$C 004.047
TrU'&c khi bat dau cong Vi$C lap d$t day th1 phai chu y cac quy d!nh an toan trong
chLI'ang cung cap di~n.
D$t d¢ng ca vao thiet bi lap d$t va noi kh&p v&i phanh ham. Noi di$n cho phanh ham
dieu khien, phanh ham dU'Q'C noi v&i phfch cam. U1p d$t day theo tr1nh ttJ ve a m9ch di$n.
CJ \ii$C thtJC hi$n cac phep do 1 va 2 can thiet cac di$n ap thanh phan tLI' 35 V den 220 V. De lam dU'Q'C dieu nay ta SU' dt,tng bien ap 3 pha v&i nhieu dau ra. CJ phan SO' cap noi di$n vao R * + S* + T* +MP* va phan SO' cap dau vao 2 pha cua d(>ng ca. Di$n ap d$t vao
cu¢n day cua d(>ng CO' a ca hai loc;:li hoc;:lt d(>ng la Uph = 220 V. NhCrng phep do dU'Q'C thtJC hi$n va d6ng trtJC tiep nhU' a nguon m(>t pha.
De do moment ma may a phep do 5, d(>ng ca dU'Q'C d6ng m9ch quay phai v&i cac tt,t di$n lam vi$C dU'Q'C dong m9ch cho nhCrng cu(>n day khac. D(>ng ca lam vi$c ngLI'Q'C 19i v&i phanh ham ch$n. Phep do dU'Q'C thtJC hi$n nhanh de tranh SlJ phat n6ng cua d¢ng ca. Phep do D$c tfnh tai den diem lc;it n, P, I, 17, coscp = f(M)
Gia tr! do:
Moment quay 8i$n ap
Cong suat vao Cong suat dLI'a ra
H$ so cong suat Moment djnh mLl'c Toed(> g6c M u (Nm); So vong quay n (V) ; Dong di$n I (A)
P1 (W) dU'Q'C do bang Watt ke P2 = 2.rc.M.n """0,1.M.n (W =Nm/ s) 60 . ri = Pz .100(%) P1 COS<p = p1 U.1
Mctm """1/2.Mrrax theo VDE cho AB co= 2.rc.n (1/ s)
60
Di~n dung cua t1;1 lam vi~c:
Gae gia tri kinh nghi$m dU'Q'C chQn trong thtJC hanh:
Nquon c6 f = 50 Hz 380V 220V
Di$n dung cho moi 20 µF 70µF
KW
Cong suat d(>ng CO'
Khoa nieih -Tr66ng TCN KTCN Hung Voong
(vong/phut)
(Nm/s)
127 V 200µF 200µF
Thf d1:1: Mot dong ca di$n 3 pha rotor I6ng s6c c6 cac s6 li$LI sau: P = 300 W, l'!,./Y
220/380V, f = 50Hz. Cho lam Vi$C & ILI'&i di$n mot pha 220V, f = 50Hz. Tfnh tl,l di$n lam
Vi$C. Giai
Tada biet: 1 000W can mÂt di~n dung la 70 àF
300 W can x µF
NhLI' vay gia tri X = 300.?0 = 21µF
. . 1000
Chon CLv = 20 µF
Tl,l di~n m& may c6 the chQn Cmm = (2+3) CLv
D9ng CO' 3 pha 6' mc;1ch Steinmetz 004.003. SO' d6 mc;1ch: R o - - - - - - - - - - - - - - - - - L1 S o - - - - - - + - - - - - - - - - - - - - - - - L2 T o - - - - - - - - + - - - + - - - - e - - - - - - - - - L3 Mp N SL PE
Khoa nien -Tro6flg TCN KTCN Huflg Vbong
Z X Y
W20 U2 0 V2 0
E>Qng cd di~n 3 pha rotor !6ng s6c: 004.003 U V W u10 V1 0 W1 0 Bangciimday Quayphai Quay trai Page 133
Phep do 8i;lc tfnh tai d§n diem l~t n, P, I, 17, coscp = f(M) m
Tv di~m lam vi~c CLv = 20 µF
M n u I P1 P2 11 COS<p Nm V/p V A w w % 0 220 const 0.25 0.5 0.75 1
Bai 4: MAY Dl~N DONG BQ
4.1. Dinh nghia va cong dl;lng: 4.1.1. Djnh nghia: 4.1.1. Djnh nghia:
NhCrng may di$n xoay chieu c6 t6c d(> quay roto n bang v&i t6c dQ quay cua tCr tmang n1 gQi la may di$n d6ng bQ. May di$n d6ng b(> c6 hai day qufm: day quan stato n6i
v&i ILI'&i di$n c6 t§n s6 f khong dBi, day quan roto dU'Q'C kich thich bang dong di$n 1 chieu. CT che dQ xac l~p may di$n d6ng bQ c6 t6c dQ quay roto luon khong dBi khi tai thay dBi.
4.1.2 Cong dl;lng cua may di~n d6ng bQ
May phat di$n d6ng bQ la ngu6n di$n chinh cua cac IU'&i di$n qu6c gia, trong d6 d(>ng CO' SO' cap la cac tu6c bin nLI'O'C, tu6c bin khi, tu6c bin hO'i nLI'O'C ... v.v. Cong suM cua cac may phat c6 the d9t den 600 MVA hoc;ic l&n hO'n va ch(mg thU'ang lam Vi$C song song. CY cac ILI'&i di$n cong su§t nh6, may phat di$n d6ng bQ dU'Q'C keo b&i cac d(>ng CO' diezen hoc;ic cac tuabin khi, c6 the lam Vi$C dO'n le hoc;ic hai ba may lam Vi$C song song.
8(>ng CO' d6ng bQ dU'Q'C SU' d1,mg khi truyen d(>ng cong suat l&n, c6 the d9t den vai ch1,1c MW. Trang cong nghi$p luy('m kim, khai thac mo, thiet bi I9nh, d(>ng CO' d6ng bQ dU'Q'C SU' d1,1ng de truyen d(>ng cac may bO'm, nen khi, quc;1t gi6 V.V ... v&i t6c dQ kh6ng dBi. 8(>ng CO' d6ng bQ cong suat nh6 dU'Q'C dU'Q'C SU' d1,1ng trong cac thiet bj nhLI' d6ng h6 di$n, d1,1ng c1,1 tl,l' ghi, thief bj l~p chLI'O'ng tr1nh, thiet bi di$n sinh ho9t v.v ....
May bu d6ng bQ dung de phat cong suat phan khang cho lu&i di$n de bu h$ s6 cong suat va Bn djnh di$n ap.
4.2. Phan lo~i, c§u t~o va nguyen Ii lam vi~c:
4.2.1 Phan lo~i va k~t c§u cua may di~n d6ng bq
a. Phan lo~i
- Theo ket cau c6 the chia may di$n d6ng b(> lam 2 lo9i:
+ May di$n d6ng b(> c1tc §n thich hqp v&i t6c d(> cao (2p = 2)
+ May di$n d6ng bQ Cl,l'C I6i thf ch hQ'p khi t6c dQ thap (2p = 4)
-Theo chuc nang c6 the chia may di$n may di$n d6ng bQ thanh:
+ May phat di$n d6ng b(>:
* May phat tu6c bin hO'i c6 n cao thLI'O'ng dU'Q'C che tc;10 Cl,l'C §n c6 tr1,1c may nam ngang. * May phat tu6c bin nU'&c: V1 t6c dQ thap, thU'ang che t9o theo Cl,l'C I6i
* May phat Diezen: Keo b&i d(>ng CO' diezen thLI'ang cau t9o Cl,l'C I6i.
+ 8(:>ng CO' di~n d6ng b(>: ThLI'ang dU'Q'C che tc;10 Cl,l'C l6i, de keo cac tai khong doi
h6i phai thay d6i t6c d(:>.
+ May bu d6ng b(:>: 8e cai thi$n h$ s6 cos<p cua ILI'&i.