giao trinh khi cu dien ha ap

Phn 1: Mt s kh c in h p thng dng

Gio trnh Kh C in H p B Mn TB- T

Phn 1: MT S KH C IN H P THNG DNGChng 1: Kh c phn phi v bo v

1-1. Cu dao

nh ngha : -Dng ng ct mng in h p khng ti hoc ti rt nh

-Cu dao ph ti : dng ct < dng ti

Cu to:

F =

F ~ chiu di li dao khng tuyn tnh vi Ict-Vi dng ln dng thm li dao ph ,bung dp h quang.Ngoi ra dng cu dao hp , ng ct t d-Lc ht h quang vo bung dp Fdd v Fdt (St non t )

-Ngoi ra dng cu dao hp, ng ct t do .Nt n ,cng tc cc loi ,cc h khng ch,b iu khin ,cu dao i ni , in tr , bin tr .. 1-2. Cu chI. Khi nim:

- Cu ch l mt Kh C in bo v mch in khi c ti v ngn mch

Cu to :

+ Dy chy: phn quan trng nht ,l ni t ra khi c s c

+ Vt liu : ng ,bc,km v ch.

VD:

Vt liu ( mm2/m ) A A A + A

ng 0.0153800001160091600

Bc 0.014762000800070000

Km 0.069000300012000

Thic 0.2112004001600

c tnh bo v:

Khi I ~ Ith : ch lm vic nng n

loi b ch trn: Dng dy chy c tit din thu hp ,dp ( H p )

Dng hiu ng luyn kimGit kim loi c tonc < tonc dy chy chy trc.+ H thng tip im:

l ni a in vo,ra khi dy chy

+ V cu ch :

Ngn khng cho h quang xut hin khi cu ch t tip xc vi cc b phn ln cn hay l ni cm tay thay th cu ch.

Phn loi:

+ cu ch h

+ cu ch na h

+ cu ch kn : cu ch khng c cht nhi v cu ch c cht nhi.

II . Tnh ton cu ch.

Bi ton 1: Bit Ith ,vti liu lm cu ch,kch thc l tm . ca cu ch

Phng trnh cn bng nhit:

I2th*R = KT*ST*(- ) R = *[1 + *(- )]*

Trong :

= 0.0159 ( mm2/m )

= 0.0043 ( )

Ith =

+ ST = *d*l

+ S =

Ith =

EMBED Equation.3 =A0*d3/2 A0*d3/2 : h s ph thuc vt liui vi hnh ch nht :

ST = 2*( a+b )*l v S = a*b

Bi ton 2: Tm mi quan h gia thi gian tc ng v dng in t = f(I)

Ta c : tt = t + t + t

Vi :

t : t khi bt u c s c cho n khi dy chy bt u chy.

t : t khi dy chy bt u chy cho n khi t v mt c

t : t lc t c kh cho n khi t in ( h quang chy )

a: Trong khong thi gian t

Ton b nhit lng sinh ra :

I2*R*dt =

Trong : I2*R*dt : nhit sinh ra : nhit t nng = t = A*()2b: Trong khong thi gian t I2*R*dt =

R= R1 + R2 trong : R1 nng chy ri R2 cha nng chy

Chy ht chiu di l

=

t = A*()2

c: Trong khong thi gian t + Vi cu ch kiu h : tt = (1.2 1.3 )*( A + )*()2

+ Vi cu ch kn c nhi: tt = (1.7 2 )*( A + A)*()2

III. La chn cu ch:

1, Chn cu ch theo ch lm vic di hn v m mya: Theo ch lm vic di hn

Xc nh dng tnh ton Itt Itt = Im =

Ta chn Im ca cu ch > Itt

b: M my :

cu ch bo v mt ng c Imcc Im c/c

trong : c = 1.6 - i vi m my ng c nng (ng c nn )

c = 2.5 - m my nh ( ti qut gi )

- Nhiu ng c Imcc Imm max / c + Im cn li cc ng c khng cng m my mt lc2, Bo v chn lc

ttd4 t0 ( 1.7 2 )*( A4 + A)*()2 A0*()2 1-3 ptomt ( My ct h p )I ) Khi qut chung:

nh ngha : - l mt kh c in dng ng ct mt cch khng thng xuyn mch in ch nh mc v t ng ngn mch khi c s c

+S c: Dng Imax ,Imin, Ucao, Uthp,Pngc bo v dng in d( Id)

Id : chnh lch I gia cc pha

Ir : dng r ra ngoi

-Yu cu i vi Aptomt: + ch I = Im th ATM khng pht nhit ,khng c sc in ng nguy him, n nh nhit , n nh sc in ng.

+ ATM phi c kh nng ct dng Ingm m khng nh hng n nhng ln ct tip theo.

+ Thi gian tc ng cng nh cng tt

+ Phi c tin cy cao

- Thng s c bn:

+ Um : l gi tr in p t vo ATM trng thi m vi thi gian v cng ln m khng lm ATM hng do phng in .

+ Im : l gi tr dng in i qua ATM trng thi ng vi thi gian di v hn m khng lm cho h thng mch vng dn in ATM hng do nhit . + Ingm : l gi tr dng in max m ATM c th ct c m khng lm h hng ATM.

+ Thng s bo v :U, f , I , ..v phm vi iu chnh

+ Thi gian tc ng: l khong thi gian s c cho n khi tt h quang hon ton.

Hnh v

Ct nhanh :

+ S dng l xo ,c cu ct tc ng nhanh

+ H thng dp h quang phi c tng cng dp h quang mt cch nhanh chng,an ton.

+ ATM xoay chiu dng c cu dp h quang kiu dn dp ( s dng cc tm st non ghp song song cch in b tr thnh 1 hp ) + Dn dng : EN60898 ( MCCB_ 3 pha )

Kiu Ngng tc ng

B 3Im It 5Im

C 5Im It 10Im

D 10Im It 20Im

+ Cng nghip : EN60947

Kiu Ngng tc ng

G 2Im It 5Im

D 5Im It 10Im

MA(A) 6.3Im It 12.5Im

- Cu to:

+ H thng mch vng dn in: u ni ,thanh dn ,tip im ( kiu ngn ) + H thng dp h quang: dng dn dp dp h quang

+ H thng to v truyn chuyn ng:

To chuyn ng bng tay

Bng NC, ng c in

Truyn bng c cu 4 khu lut khp

+ Phn t bo v trong ATM

Bo v qu ti dng rle nhit

Bo v ngn mch : Rle dng in

Bo v bng in t s

+ V v cc thit b bo v khc

Phn loi :

- theo thi gian

Tc ng nhanh Bnh thng Chm

< 0.08 s 0.08 0.15 s >0.15s

theo cng dng:

+ ATM vn nng

+ ATM nh hnh

+ ATM tc ng nhanh

II, ptmt vn nng

1, ptmt vn nng kiu in t :

- Cng sut ngt ln ( 400 A,Im )

- Nhiu thng s bo v,phm vi bp v rng

Thng khng v v c lp ngay vo t in ,dung u ngun

* Xt ATM vn nng kiu in t:

1: Bung dp h quang 9: Rle dng in t cm

2: L xo tip im h quang 10: Rle in p thp

3: Tip im tnh h quang 11: NC ngt

4: Tip im tnh chnh 12: Tay cm

5: Tip im ng chnh 13: NC ng

6: Dy ni mm 14: C cu 4 khu7:Rle nhit 15: L xo ngt

8: in tr 16: L xo tip im chnh

III, La chn ATM1. Thng s ca ATM

Im Itt

Ingm Ingmax

ttt tbn2. Chn ATM theo iu kin bo v chn lc : tc ng ng ch

CHNG 2 . KH C IN IU KHIN

2-1 . CNG TC TI. Khi qut :

Cng tc t l KC dng ng ct mch in h p mt cch thng xuyn ( c th ln ti 1500 ln /h ) t xa ( bng tay hoc t ng ).

- Cu to :

+ H thng mch vng dn in (u ni,thanh dn , tip im( chnh ,ph),cng tc t 1 chiu s dng tip im hnh ngn, cng tc t xoay chiu s dng tip im bc cu,1 pha 2 ch ct). + NC:

Mch t : 1 chiu lm bng thp khi hoc xoay chiu lm bng l thp k thut in ,vng ngn mch.

Cun dy: dng dy ng KT

Do NC 1 chiu nhiu u im hn xoay chiu cho nn hu ht cc cng tc t s dng NC 1 chiu k c cng tc t xoay chiu

+ V v cc chi tit khc: cc thng s c bn

+ Um : l gi tr in p t vo cng tc t vi khong thi gian v hn m khng lm cng tc t hng do in p ( trng thi m )

+ Im : l gi tr dng in i qua tip im chnh ca cng tc t trng thi ng m khng lm cng tc t hng do nhit

+ Ing ,ngt :dng max khi ng ngt m khng lm cho cng tc t h hng do nhit ,Ig = Im,Ing = 5 Im.

+ Uk : l gi tr in p t vo cun dy NC ca cng tc t ( 0.8 1.1 Um )

+ Cp cch in ,ch lm vic ch yu di hn

+ S lng tip im: 3 hoc 4 tip im chnh ,2 tip im ph.

Phn loi :

+ Cng tc t in t ( cng tc t c iu khin )

+ Cng tc t in t ( khng tip im ) Cu to gm cc van ng lc ( thyristor.triac )

2-1 KHI NG T

nh ngha : l TB dng ng ct v iu khin t xa cc mch in ng lc hoc o chiu quay v bo v ng c

Cu to : gm

+ Cng tc t (ng ct )

+ Rle nhit ( bo v )

Phn loi :

+ Khi ng t n : 1 Cng tc t v rle nhit

+ Khi ng t kp : 2 Cng tc t v rle nhit1. Khi ng t n :

Tc dng : ng ct v bo v mch in cng nh ng c khi b qu ti.

S mch in

Nguyn l :

M my ng c : ng CD, n D K c in tip im K1,2,3 ng C quay Dng ng c : n N K mt in K1,2,3 m C dng

+ Khi qu ti RN tc ng tip im RN m K mt in K1,2,3 mC dng

Thay th cu dao ,cu ch bng ATM

2. Khi ng t kp:

Ngoi chc nng ging KT n cn thm chc nng o chiu quay ng c

ng c khi ng thun : ng CDn DT KT c in tc ng KT ng ng c quay thun

Mun ng c quay ngc n nt D ng c dngNKN c in K~ ng

trnh tnh trng 3 cng tc t hot ng ng thi gy ngn mch cc pha ngi ta s dng tip im ph thng ng ca cng tc t ny khng ch cng tc t kia v ngc li

bo m an ton tuyt i ngi ta cn s dng kho lin ng c kh gia cc nt n.

3. Rle nhit

Dng bo v qu ti cho thit b in c tnh bo v : t = f(I) (A/s)

m bo yu cu bo v qu ti cho ng c th c tnh qu ti ng c phi nm thp hn v gn st vi c tnh bo v ca rle nhit . Chn Imc = ImRN

ItRN = (1.2 1.3)Im

Ta c th iu chnh dng tc ng ca Rle bng cc nm iu chnh trn Rle

Rle c th c 2 hoc 3 phn t t nng

CHNG3 . C CU IN T CHP HNH

1 . KHI NIM CHUNG

L cc thit b in chp hnh dng thc hin mt cng on nht nh trong qu trnh cng ngh nguyn l lm vic l nguyn l in t. NC l b phn ch yu ca CCT chp hnh v l b phn sinh ra lc t cho c cu lm vic .

Ch yu dng NC 1 chiu v :

+ Khng tn hao st cho nn mch khng b pht nng

+ Lm vic m ,khng n do b rung

+ I khng ph thuc vo khe h khng kh

+ Dng c quy thay th c khi mt ngun in li2. KHP LY HP IN T

nh ngha : l c cu in t chp hnh dng truyn mmen trc dn sang trc b dn v iu chnh tc quay ca trc b dn bng qu trnh in t.

Phn loi:

- Kiu ma st

- Kiu bm

- Kiu cm ng

- Kiu t tr

1. Khp ly hp in t kiu ma st:

a, Tc dng : dng truyn mmen t trc dn sang trc b dn nh lc ma st c sinh ra khi cc a ma st b p cht vo nhau di tc dng ca lc in t.

b, Cu to:

c, Nguyn l: - Truyn M t 19

+ a I vo cun day qua 2 (IW)

EMBED Equation.3 qua (3,6) to ra Ft

EMBED Equation.3 ht 6 chuyn ng sang tria ma st b p cht vo nhau8 b nn d tr nng lngkhi a ma st ni lin th ni lin 2 mt quaykhi 1 quay3 quay6 quay7quay9quay -Mun khng truyn mmen ngt inFt = 0Fphn8 lc y 6 sang phi Fms = 03,6 tch ri.

Mms = =

Rn,Rt bn knh trong ,ngoi a ma stLeins : hng s

= h s hnh dng ca a ma std, c im:

- a ma st c lm bng vt liu c h s ma st ln ,chu mi mn v chu nhit cao,thng dng kim loi gm.

- Q khp ma st ch c tc dng ng ngt ( ly hp ) m khng iu chnh tc quay ca trc dn v mun iu chnh tc quay trc dn ta phi gim Ikt Fms gims trc trn cc i tng gia cc a ma st nhit a ma st T cao ph hu a ma st.

- Do s dng chi than vnh trt cho nn tui th ca khp gim

2. Khp ly hp in t kiu d

a, Nguyn l: da vo nguyn k cm ng tng t nh nguyn l ca ng c KB lng sc.

b, Cu to:

i

EMBED Equation.3

EMBED Equation.3

EMBED Equation.3 Khi 1 quay

EMBED Equation.3

EMBED Equation.3 i xoy 1 tc dng gia i xoy v t trngMq 2 quay theo

truyn Mln vt liu in t tt ,Ixoy nh,ta c th iu chnh tc quay trc b dn bng cch thay i dng kch t NC

3.Khp ly hp in t kiu bm:

- Tc dng : truyn mmen t trc dn n trc b dn nh lc bm c sinh ra do lin kt cng ca bt st trong t trng

THIT B CP NGUN D PHNG ATS

iu kin m my ca ng c 660/380 (380/220) khng dng

Sng mang fc,

Sng iu bin f2

loai dung rle dong in

Phn II: Ly Thuyt Thit K

Chng 4:Nhng vn chung v thit k khi cu in ha ap

Bai 4-1 Khai nim chung

- Khi cu in ha ap chia theo in ap : - cao ap :phn phi, bao v, o lng.

- ha ap :phn phi, bao v, iu khin, khng ch

- Cac b phn :

+ h thng mach vong dn in:

u ni (1)

Thanh dn (2)

Tip im (3)

- F

(1) chon dang : han

c, vit, ., Rtx< RTx cho phep

Inm, Im

(2) chon dang : tron, vung, ch nht..

Chon J- mt in dn vt liu phu hp

(3) chon dang tip im, kich thc cua tip im, khe h khng khi ( lc gia tip im ng va tinh ), mon cua tip im, khng xay ra phong in

+ H thng dp h quang : chon dp ( p/a ),

Kich thc : - Khe hep : RM, l, day

- dan dp: s tm,

- c bit : du, khng khi nen, SF, T sinh khi

+ c cu tao truyn ng : - Tao : nam chm in, ng c, thuy khi

- Truyn : lo xo ngt, lo xo hoan xung, c cu truyn.

+ Chi tit cach in:

Um ( thit bi) tim c in ap phong in Uph ( khoang cach ti thiu

Smin pha- pha, pha - t

- Cac yu cu chung

+ ky thut: - n inh nhit Tnhit1,3,10 (thoi gian)

- n inh in dong

- bn cach in

- bn c khi: mon, cng

- kha nng ong, ct ( Im, Inm, Nc, N )

Nc = 5 - 10 Nin

- yu cu ring

+ vn hanh : - chiu c anh hng cua mi trng xung quanh

- tin cy cao

- thi gian s dung lu dai

- n gian, d cha, d thay th

- chi phi vn hanh thp, tiu tn it nng lng

- kinh t xa hi : gia thanh ha

d vn hanh

an toan

tinh thm my

- cng ngh san xut : d ch tao

tinh cng ngh

lp ln, qui chun

tinh phat trin

* Trinh t thit k khi cu in

1- chun bi tai liu : nhim vu th

2- chon phng an thit k _ tham khao cac mu khac nhau, nn cng ngh

3- chon tinh toan cach in pha-pha, pha-t

4- ve kt cu s b va xac inh cac h thng chu yu

5- thit k mach vong dn in ( thanh dn, tip im va cac u ni )

6- thit k h thng dp h quang

7- tinh cac F

8- thit k c cu tao va truyn chuyn ng ( nam chm in- ng c in-h thng truyn ng )

9- tinh toan vo, cac chi tit cach in

10- tinh toan nhit

Bai 4-2 Chon khoang cach cach in

- kich thc

- da va kinh nghim

- trinh t : - cn c vao Um - Uth - khoang cach cach in ti thiu Smin

( dung cng thc kinh nghim hoc tra bang)

- b mt m t va bn thi tng khoang cach S

- t hp khi cu in t canh nhau thi tng khoang cach S

Bai 4-3 tinh toan mach vong dn in

I, Tinh thanh dn- xac inh kich thc thanh dn

- cn c vao Um da vao bai toan nhit tim ra kich thc thanh dn ( ch dai han )

Sau o kim tra thanh dn ch ngn han

a) kim tra thanh dn ch dai han

p = KTST ( ) = I2R

Pdt = Gp*c*d*T +KTST Tdt

I2*= KTST ( )

b) Kim tra phat nong ch ngn han

ng, cach in cp Y ( 90 C)

ch dai han Idh = 200A

T = 180 (s) hng s thi gian nhit

ngn han Tlv = 10 s In.han = ?

ngn han lp lai Tlv = 10 s I=?

Pdt = G.c.d + KTST(-)dt

Inm2 Rdt = V*d

Bai 4-4 : u Ni

1) Yu cu

- ch lam vic dai han, nhit khng c phat nong qua nhit cho phep

dai han To < [ T ] , RTX ( UTX ) < [ RTX ]

( [ UTX ] , Ft [ Ft] )- Ngn mach

bn c, nhit : am bao.

- Vn hanh : nng lng tn hao Ptx nho, Rtx nho

- Ft C, tin cy

2) Trinh t tinh toan :- chon dang kt cu : tuy theo hinh dang thanh dn ( sgk)

- xac inh kich thc c vit cho u ni thao ri

+ Im ( Stx cn thit = I m/ J ( J = 0,31 A/mm2 )

+ chon c vit

. Stx - Ft cn thit

= f t.Im

. chon ( 2- 10- sgk )

Bai 4-5 Tip im

1) Cac loai tip im :

- lo xo la, tx cong- son, bc cu, lem,..

2) Yu cu

- - Idh : T < [ T ]

- Inm : bn c, nhit

- rung < [ ], mon < [ ]

Xrung g

Trung G ( z ln ong ct )

3) Thng s :

- m m ( ng tinh )

Im < 200 A 4 ( Rle ) - 12 mm ( Cng tc t, ATM)

- kt cu tip im : 1 ch ngt u/n

n ch ngt

xac inh kinh nghim -leno sau tinh bung h quang

+ m cang ln thi len dp h quang cao - kich thc thit bi ln - hao phi vt liu , P

- lun : la quang ng co th i tip cua tip im ng khi khng co tip xuc tinh

l = A + BIm A = 1.5 2.5 mm

B = 0,02 mm2/A

220v, 5 A

m = 4 mm

l = 1.5 + 0,02.5 = 1,6

INCLUDEPICTURE "../../Program%20Files/VietFlex.2UV/Convert.ICO" \* MERGEFORMAT

= 5,6 mm = m + l

380 v, m = 6 mm

kim No theo mon tip im

G = z ( g Ig + gngIng ) ( z- s ln ong ct )

G/



=V

l = ( 1,5 2,5 ) h

- khoang ln : Tao tip im h quang va tip im lam vic

x = 3 12 mm ( - I nho )

I-, c 40 A

- khoang trt

+ lam sach bn do bui, h quang, h quang sinh ra ( gh gh)

y = ( 0,2 12 mm )

- lc ep tip im :

ft = ( 0.4 0.7 ) ftc

ftc = fIm = ( 7 15 ) g/A

4 ) Chon vt liu vao ht tip im

A Chon vt liu

a) yu cu

- in tr tip xuc be

- Tinh dn in va nhit nong chay vt liu cao

- it bi oxi hoa

- Kho han dinh

- cng cao it bi n mon

- c tinh cng ngh tt

- Gia thanh ha

b ) chon theo 2- 13 2- 14 Im 10A < Im < 2000A : kim loai gm : Ag_Ni_Cg

B_ Kich thc tip im ( 2- 15 , 2- 16 )

-t cu Im = 5A chon d= 4mm

40A chon d = 12mm

5 )Xac inh nhit tip xuc, in ap tip xuc, lc ep tip im va in tr tip xuca) Nhit tip im

- phng trinh cn bng nhit :

- in trng va nhit trng :

Ft1 = I2m A Ttx = Tt + ( 5 10 ) 0 k

- Ttx = Tt/cos(Im - Im = 4b) in tr tip xuc

R

R1_ do s co hep cua dong in

R2_do tip xuc b mt

Tinh Rtx = (ly thuyt )

Rtx = K / (0,102.Ft)m ( thc nghim )

m = 0,5 im

0,7 1 mt

0,5 0,7 ng

Theo ng cong tno 2- 10, 11, 12

c) lc ep tip im

- Theo Rtx Ft

- Thc no Ftc = ft.Im Ft bang 2-17

Ft = (0,5 0,7) Ftcd) Utx

Utx = Im.Rtx bang 2 -18

[Utx ]= ( 0,5 0,7 ) Um ( /a lam vic cho vt liu hoa mm )

6) Dong in han dinh, bin phap khc phuc chng dinh

idt > Inm , i ong, i cta) Ly thuyt :

Ithhd = 4


.arcos( (Tt - Tt.e-t1/T)/(Ttx - Ttd.e t1/T) )

T- hng s thi gian phat nong tip im

t1- khoang thi gian t luc tip im bt u ong n luc han dinh

b) Tinh Ihd ban u theo Utx, ttx

Ihdb = A



A = fnc- anh gia s tng din tich tip xuc ( 2 4 ln )

c) Tinh Ihdbd theo Rtx , Unc Ihb = 2Unc


d) Thc nghim :

Ihdb = KhdBin phap chng dinh

- tng Ft, giam rung

- 2 tip im co vt liu khac nhau

- Phai la chon kt cu sao cho l sinh ra cung chiu vi lc ep t

- Dung vt liu kim loai gm

7) S dung tip im, bin phap chng rung

- Hai thng s: Xm Bin rung

Tm Thi gian rung

A. Tinh toan oan Xm , Tma. Tip im la lo xo la, tip im tinh c inh -> role ct t

Xm = m M 2Ft u h = fg/A

V = ( 0,1 1 )m/s

c. Tip im hinh non co lo xo xon tru -> ct t 1 chiu = ct t xoay chiu tng lc ep tip im

- giam t phn ng

- giam lu phn ng

- giam lc tac ng ln phn ng

- Dung lo xo xon xung trit tiu in nng tha phn ng

8. S mon cua tip im va cac bin phap khc phuc

- Mon do

+ C khi

+ Mon do in (tac dung cua hquang)

U>U0 hq x h

i>i0

U>U0 -> hq ngn

IU0 -> khng x h hq

I Uo Ing < Io < > vng = K1KI- Ung > Uo Ing > Io v ong = V ng = (Q_ in lng i qua 2 tip im trong qua trinh ong ngt

* xoay chiu :_Tinh gn ging 1 chiu ( skg )

b) Tip im cua KC U ( 30 V , I ( 200 A

V + Vng = (+ ) IngTtng ln

+

EMBED Equation.3 .I

Khq- h s tinh n thi gian rung co h quang (0, 3 0,7 )

T


= ( 1,5 1,8 )tm

c) KC phn phi va iu khin n 1000 V g + gng = 10-9 ( KI2 + KngI2ng ) KkKk : mon khng u ( 1,1 2,5 ( 3 ) )

d) KC cao apC_ Cac bin phap chng mon

- la chon vt liu :

- giam thi gian chay cua h quang

+ Tng tc ban u cua tip im trong qua trinh ngt.

+ chon cng t trng cua cun thi t ti u

- giam thi gian ong cua tip im

- dung cac bin phap kt cu

+ tng bt cua nhng ni tip im hay bi mon

+ s dung cac tip im t inh vi tip im mon ng u

+ b mt tip im phai gia cng bng phng

CHNG 5 H Thng Dp H Quang

Bai 5.1 Khai Nim Chung

Ungun ( t/c ngun, xoay chiu ) Chon kt cu

Im Thng s cua bung

Ing T/c tai Hoan thin thng s tip

Thi gian ngt im

St, lthlq, dhq, vhq -Khe hep ( 1 chiu )

-n, -Kich thc cun thi t 1 chiu T do

Khe hep

Cun thi t

Xoay chiu : dan dp

_ h quang qua trinh vt ly phc tap dung cac cng thc thc nghim

Phat sinh phat xa ngui in t

phat xa in t do nhit K

ion hoa do va cham thn h quang

ion hoa do nhit thn h quang

Dp tt tai hp

khuch tan

_ U INCLUDEPICTURE "../../Program%20Files/VietFlex.2UV/Convert.ICO" \* MERGEFORMAT

1000 V, 30 KA Ing = 15 Ima) yu cu :

- phai am bao kha nng ong ct cua bung dp

- thi gian chay cua h quang phai nho

- phai co kha nng khng gy ra qua in ap ni b

- kich thc nho, kich thc vung chay h quang nho

- han ch anh sang va m thanh

b) gia tri dong in ngt

Bai 5.2 Vt liu va kt cu bung dp h quang

I) Vt liu

_ yu cu: + phai chiu c nhit cao

+ chng m

+ nham b mt

_ 3 loai vt liu: + xi mng-aming

+ composit

+ gm

II) kt cu ( 91-93 )

Bai 5.3 Cac thng s h quang lhq, dhq, vhq, thq cua

h quang chay t do

_Chu vi h quang

+ ng tron

_ chiu dai

St = vt.t lhq = S2t + 9h2hq

Hhq = vhq.t

lhq = 2

EMBED Equation.3 vhq.t

_ ng kinh h quang dhq

H quang khng di chuyn dhq = 0.27Ing ( cm ) + di chuyn vhq dhq = 1.12

EMBED Equation.3 ( cm )

_ vn tc h quang

Vhq = 0 100 cm/s

F, Ft ( cun thi t )

Vhq


0.5 Ing ( cm/s ) sau o kim tra lai

- thq Thq =

Bai 5 4 Tinh toan gn ung bung dp h

quang 1 chiu

I, Khai nim chung

+ s liu cho trc

- Ung = 1,1 Ungun - Im, Ing - T/c mach ngt L, R, C

- sln ong ct trn gi

Ts ong ct : - phn phi - k 150 l / gi

+ trinh t

- cn c vao /a ngun va chiu dai ti han h quang

- xac inh chinh xac m cua T

a) chiu dai ti han

- cn c vao thng s mach, /a ngun xac inh Lthb) anh hng cua in cam n chiu dai h quang

lhqth = K.Ung.I

ng c : 150 hw K = 0, 013

750v

c) Qua in ap

I) cac yu t anh hng n bung dp h quang

1) in cam mach ngt

Tt = UR

Ungt = Ung( 1 + )2) Tn s ngt

F = 100 ln/h thi lhqth = 2 ln lhqth khi f = 2

3) tc mi cua T

Vt = 100 cm/s k nng ong ct tng 10 ln , 15% so vi cac loai v = 1 cm/s

4) cac yu t khac

Mi trng : m

ap sut : cang cao ln dp h quang cang tt

T0

III, Dp h quang bng cach keo dai h quang bng c khi ( h quang chay t do )

1) thi

- chi ng h quang chay t do trong khng khi

- sau khi tra /c ly hng s d tr c 1,3 2 ln

2) Cng thc kinh nghim

Lhqth = 0,42.10U

EMBED Equation.3 [cm]

IV) Dp h quang bng cach keo dai h quang bng l

a) xy dng V-A theo tng gia tri Lhq

b) tinh theo cng thc kinh nghim

I 200A : Uhq = lhqth. .V=

I > 200A U

K1= 2 f0 .Kbd (Kbin )

B4: Xc nh thi gian chy h quang thq1/2

B5 :Xc nh chiu di nh nht ca cc tm dn dp

(cm)

B6: Xc nh biu thc ca bung dp

- Cc tm phi lm bng thp g

lhqth =

V) Dp hq bng cch ko di hq bng t trng ngang:

5.5 Tnh ton gn ng bung hq in xoay chiu

I) Khi nim chung: 1) c im hq in xoay chiu:

+ Dng in trong 1 chu k bng 2 ln

+ Khi thit k cn thit k dp hq ti i=0

+ iu kin dp tt Uct > Uphc hi

Uph dao ng Uph 2Ungmax

Uph khng giao ng Uph Ungm

Gi tr bin ca in p phc hi c xc nh

Ungmax = Uphmax = Ungtm =

Trong :

- U m : in p nh mc cu li

- : gc lch pha gia dng in v in p

- Ks : h s s

+ Ngt mch 3 pha thng qua 3 cc:

Ks = 1,5

+Ngt mch 3pha -3cc trong trung tnh ca ngun c ni vi v tiu c

Ks = 1

+ Ngt 1 pha 1 cc Ks = 1,73

+ Ngt 1 pha 2 cc Ks = 0.865

Tc tng trung bnh ca in p phc hi ca qu trnh dao ng

2 Kbf0Ungun

Trong :

Kb : H s bin

+Vi trng hp hq chy t do

Kb =1 + e -0,0003 f

f 0 : tn s ring ca mch ngt

Trong LC l t cm , in dung ca mch ngt

+ Ngt ng c P= 50 kw ,

EMBED Equation.3 (

EMBED Equation.3 ) (Hz)

(1) Dy cp :3 dy t trong 1 cp (A,B,C)

(2) Dy kh : 3 dy t song song ngoi

Trong (1) A = 8000

B = 2100

(2) A = 15000

B = 3000

+ Ngt cun dy in t :

f 0 =

Trong :

N : l s vng dy

l : l chiu di trung bnh ng sc t

S : l tit din cc t ( mch t)

: l khong cch khe h kh ng ct

2) m tip im :

- i vi cc thit b ng ct xoay chiu m khng ng vai tr quan trng nh i vi cc thit b mt chiu v c tip im ng qua 0 cn dng khng qua 0

- Tu theo cp ph ti hoc cng sut ca thit b ng ct cng nh dng in v in p . m c chn theo h s (0,5 11)mm

3) Cc s liu biu thc cho trc tnh ton

+ Ung : l in p in mch ca ngun cung cp (gi tr hiu dng)

+ Ingt : l gi tr hiu dng

+ 0 : l gc lch pha ban u ca dng in v in p

+ f : l tn s ca ngun cung cp

+ f0: l tn s ring ca mch ngt

+ Ks : l phng php ngt

+ z : l tn s ng ct ( s ln ct /1h)

+ l: l in cm ca mch ngt

II) Dp h quang 2 chiu chy t do c 2 ch ngt

Dng ch yu trong cng tc t xoay chiu h p

Yu t dp hq xoay chiu chy t do 2 ch ngt

+ bn in ban u hay bn in phc hi

Uph= U0ph + K (V)

Trong :

U0ph : bn in phc hi ban u ph thuc vo gi tr dng in ngt ,tn s ngt

Kt : tc tng ca bn in phc hi

th:

EMBED Equation.3

Tip im lm bng vt liu ng m l vng , bc..th cc h s xc nh cn phi nhn thm 1 h s gi l h s vt liu (tra bng)

Chiu di hq trn 1 ch ngt c xc nh nh sau :

TH1: I = (80 200)A

(cm)

TH2: I>200A

(cm)

Trong :

= vtd.t

t cui thi im ct

vtd vn tc m thi im thng l 0,1 cm/s

t thi gian chy h quang ( Fc 6.5 Tnh ton l so

1) Chn vt liu

2) Xc nh s vng , d , D

Chng 7 : Nam chm in

7.1 Khi nim chung

- Bin in nng thnh c nng

+ Nu thng : Dch chuyn nh

+ Nu quay : gc nh

- Hin tng vt l phc tp , khi thit k dng cc cng thc thc nghim

- Tu theo yu cu thc t m la chn cc dng nam chm in khc nhau

- Xt trnh t thit k

+ Khng c vng ngn mch

+ C vng ngn mch

bin thin xut hin lnm

lnm

enm = chng li bin thin ca

lch pha gc

EMBED Equation.3

EMBED Equation.3

EMBED Equation.3 +

EMBED Equation.3

EMBED Equation.3

=> l tng

=> Khng c chng rung

iu kin chng rung l tng

Khi s2=2s1 th Bm = B2m

Fbdm =2F01cos = 0

EMBED Equation.3 rnm=0 Khng tn ti trong thc t

Chn =(5875) tho mn

Fmin>Fp

7.2 Cc thng s c bn v nhim v thit k

A) Cc thng s vn hnh

- Tu dng kt cu

- Ngun in

- Ch lm vic

- Cng sut tiu th

- Nhit pht nng cho php

- Cc thng s v ht v nh

Ut : in p t vo cun dy nh nht ht

Unh: l in p ln nht nh hon ton

ttd = t1+ t2 tnh= t3 + t4 Nc , N tn s ng ct Khi lng NC Kch thc lp ghp

Gi thnh

B) Cc thng s v cng

- Cng l thuyt iht , ht- Cng ton phn l cng t m ht

- Cng hu ch : l cng(m ht)

C)Nhim v thit k

1) Bi ton thun :

Fcs kch thc , thng s NC( thit k s b)

2) Bi ton ngc

T NC c tnh c tnh lc ht

Xy dng Ucd = (0,85 ; 1 ; 1,1) Ucdm (kim nghim NC)

D) Trnh t th NC - Xc nh thng s NC - Tnh ton s b

- Tnh ton kim nghim : vi NC thay i phi tnh vng ngn mch

7.3 S liu ban u

G Gs

Gr r , t Gt Iw Ft W,d ktcx

tt ,tnh , knh

1) Cc s liu v c cu

- chu va p chu rung

- Lc v hnh trnh c cu

- Ch lm vic

- in p ngun

- Mi trung xung quanh v nhit cho php

- Cc ch tiu v th ti u NC- Cc yu cu ph khc , thi gian ng , nh , cng sut tiu th cun dy

- Yu cu v cng ngh ch to

- Phm vi sai s cho php ( lc ht , khe h

- Vt liu v cc thng s v h s

7.4 .Chn dng kt cu

c tnh lc ht

Phi hp vi c tnh c H s kt cu 1 chiu

Dng NC 7.5 Chn vt liu t

1 chiu : thng dng dng khi , chn st t mm B max

Xoay chiu : chn l thp KTB : nu mun cho thi gian tc ng nh th B nh

(0,4 0,6) T

Khi Bm =( 1,6 1,7)

7.6 Xc nh kch thc ca NC

I) Kch thc mch t

- T c tnh c , chn im nguy him Fcth Fttt = Kt . Fcth Kt l h s d tr

Tm in tch cc t S

Fttt= 4,06.B2s..104 (m2)

Chn B = 0,3 1 tesla

Bng = Bnh .r nh

ng hon ton r ng = 1 1,05

M r m = 1 4

1 chiu

dm li =

S = a.b ( Chn a b )

II) Kch thc cun dy

1) Xc nh St tc ng

1 chiu:

(Iw)t = (Iw) nh + ( iw) p nh + (Iw)Fe ; ( iw) p nh + (Iw)Fe = (0,51) (Iw)t

(Iw)nh = .=

~ chiu :

(Iw)t = (Iw) nh + (Iw)ht

Kim tra :

J = 2A/mm chn Kl = 0,30,6

III) Kt cu nam chm in v xc nh kch thc

7.7 Tnh ton t dn ca mch t

Grt 1 chiu gl = Grt gl = Grt

Xoay chiu

V mch t ng tr , xc nh r , t

7.8 Tnh ton kim nghim nam chm in 1 chiu

1) Tnh v dng c tnh lc ht

2) Tnh cc thng s cun dy

3) Tnh ton nhit cho cun dy

4) Hiu chnh cc kch thc ca nam chm in nu thy cn thit

5) Tnh th gian ht nh

6) Tnh h s nh

Unh inh Fnh

Knh= = =

Ut it Ft

7.9 Tnh ton kim nghim nam chm in xoay chiu

Ft = Fk -

Tnh ton vng ngn mch

Fmin > Fp

(1) Fp1 : Cho 1 hnh v h c vng ngn mch

FP1 = Fp/4

(2) Fp1= Fp/2

Tnh vng ngn mch

+ Tnh :

Fht = 4 . B2. S

= 2.B2m .S - 2.Bm .S.cos2t

Ftbht = 2.B2m .S.104 =(KG)

S= Sn + St (m2)

+ T s :

Fmin = Fp1 . Kt( thng ly = 1,2)

+ = Sn/St 0,5

+

Hay

=>

Gt1 : t dn i qua khe h trong

+ rnm tg

+ Tnh v ng ngn mch

Kim tra

Khng tho mn

Kim tra iu kin chng rung

Th vng ngn mch

q=a .b ; a < 2mm

V d

Kch thc vng ngn mch

a = 1,5 mm

b = 6 mm

ng

gi s B1 = 1,4 T , h = 0,5

B2 = 1T

S = S1 + S2 = 17mm

Fp = ? nam chm in khng rung

f = 50 Hz

220o = 0,025mm2/m

= 450

Fmin=Ftb - Fbm

F1tb = 4 .B21.S1 = 4. 1,42.0,75 7, 2 KG

F2tb = 4 .B22.S2 = 4.12.1,5 = 6 KG

Ftb = 13,2

= F1tb + F2tb

(KG)

Fmin = 13,2 9,2 = 4 (KG)

Fp 8 KG nam chm in khng rung

tn hao

Cu hi n tp

1) Cu ch : Cng dng , cu to , tnh ton cu ch v cch la chn

2) p t mt : Cng dng , cu to , tnh ton v cch la chn

3) Nu nguyn l lm vic v cu to ca AT vn nng

4) Cng tc t : Cng dng , nguyn l cu to , cc thng s c bn

5) ng dng ca cng tc t cho 1 s mch in thng gp song song cng tc t c tip im v khng c tip im

6) Phng php xc nh khong cch in trong kh c in h p

7) Cu to , c im ca mch vng dn in

8) Xc nh kch thc ca thanh dn ch lm vic di hn , kim nghim ch lm vic ngn hn

9) Cc loi tip im , phm vi ng dng

10) m , ln , khong ln , khong trt ca tip im

11) in tr t0 tip im

12) S rung , s hn dnh ca tip im , cc bin php chng rung , hn dnh

13) S n mn ca tip im , cc bin php chng mn

14) Tnh ton , kim nghim h thng dp h quang in 1 chiu

15) Tnh ton , kim nghim h thng dp h quang in xoay chiu

16) Tnh ton v dng c tnh c

17) Cc bc tnh ton s b nam chm in

18) Tnh ton kim nghim nam chm in

19) Thi gian tc ng v h s nh nam chm in

I(A)

t (s)

I(A)

t (s)

1

2

3

4

0

ct nhanh

I

t

I(A)

t (s)

PAGE Su tm : Thy gio Triu Vit Linh - i hc BKHN -7-

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