Hd Thuctap Quanday-bai 1

7/30/2019 Hd Thuctap Quanday-bai 1

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1.1. YEU CAU THC HIEN : Sinh vien da tren kch thc loi thep ang co san va s o nguyen ly cua

bien ap mot pha yeu cau thc hien; tnh toan so lieu day quan bien ap. So lieu tnh toan day quan phai ay u cac thong so sau: So vong day

quan (pha s cap va th cap); ng knh day quan (day tran) va ng knhday tnh en lp men (email) cach ien boc xung quanh . Khoi lng day quan.

Kiem tra ieu kien lap ay; va c tnh so vong mot lp va so lp trc khithi cong.

1.2.MUC CH : Bai thc tap 1 giup sinh vien nam vng cac van e sau: Ap dung phng phap tnh toan day quan bien ap theo ly thuyet vao mot loi

thep bien ap cho trc. Giup sinh vien hieu ro y ngha cua cac thong so tnh toan neu trong ly thuyet

nh : he so lap ay, so vong mot lp va so lp. . . Da vao thong so tnh toan theo ly thuyet cho day quan, chung ta thc hien

viec bo tr cac au ra day bien ap ung tieu chuan nhng tao c net my thuatcho bo day bien ap.

1.3.NOI DUNG THC TAP :

Qua trnh thc tap tien hanh theo cac bc nh sau:

BC 1 : o cac kch thc tieu chuan cua la thep E,I .

Khi s dung loi thep E, I; sinh vien can o cac kch thc sau (xem hnh1.1) neu s dung la thep E, I ung tieu chuan.

b

a hc a

a/2

a/2 a/2

a/2

HNH 1.1: Cac kch thc c ban cua loi thep dang E,I .

BAI 01


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Ky hieu va ten goi cac kch thc c ban cua loi thep:a : Be rong tru gia cua loi thep.b : Be day cua loi thep bien ap.c: be rong ca so loi thep .h: be cao ca so loi thep.

Cac kch thc nay khi o tnh theo n v [mm] hay [cm].

CHU Y: Cac kch thc a , c va h c o trc tiep tren mot la thep E , I. Dung cu o la thc kep (sai so 1/50 mm). Rieng kch thc b c xac nh gian tiep bang cach o xac nh be day

cua moi la thep E, I ; sau o em tong so la thep E va tong so la thep I. T o tnhra be day loi thep bien ap bang cach ap dung quan he sau:

)()1( theplasoTongxthepladayBeb= (1.1)

Vi la thep ky thuat ien tieu chuan thuoc dang tole can nong hay can lanhvan hanh tai tan so f = 50Hz, be day tieu chuan cua la thep thng thuoc mottrong hai c sau : 0,5 mm ; hay 0,35 mm. Kch thc tong quat cua toan bo la thep sau khi ghep sat c xac nh

theo hnh 1.2. Chung ta co the tnh khoi lng loi thep bien ap (dang tieu chuan)theo quan he (1.2).

HNH 1.2: Cac kch thc ngoai cua loi thep

Sau khi xac nh cac kch thc loi thep, chung ta tnh tiet dien tru giacua loi thep ch E . ay chnh la tiet dien cho t thong chnh moc vong xuyen quacac bo day quan.

Goi At : tiet dien tru gia loi thep, ta co:b.aA t = (1.3)

Trong o; n v o : [At] = [ cm2] ; [a] = [b] = [cm].

b

a hc

2,5 a

3 a Goi WFer la khoi lng cualoi thep bien ap, vi gia tr khoilng rieng cua loi thep la 7,8kg/dm3 ; khi biet c cac kchthc c ban a, va b chung taco quan he sau:

baWfer ..8,462= (1.2)

Trong o, n v o cxac nh nh sau:[Wfer] = [Kg] ; [a] = [b] = [ dm]

tnh ton li thp


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BC 2 : Xac nh gia tr nv (so vong day quan tao ra 1 volt sc ien ong cam ng) .

Trong bc nay chung ta thc hien hai thao tac:Chon mat o t thong (hay t cam) B dung tnh toan cho loi thep.Ap dung cong thc tnh sc ien ong tao ra trong day quan bien ap e

tnh so vong tao ra 1 V sc ien ong cam ng (xem quan he 1.4)

tv AB

n.45

= (1.4)

Trong o, n v o c xac nh nh sau:[nv] = [vong/volt] ; [B] = [T] ; [At ] = [cm2]

CHU Y: Vi la thep ky thuat ien co be day tieu chuan 0,5mm en 0,35 mm; la thep

thuoc dang tole can nong va ham lng Silic t 2% en 4%; chung ta chon gia trmat o t thong B = 1T en B = 1,2T (ham lng Silic thap, t cam B chon thap). Lathep ky thuat ien thuoc dang dan t ang hng. Vi la thep ky thuat ien co be day tieu chuan 0,5mm en 0,35 mm; la thep

thuoc dang tole lanh va ham lng Silic khoang 4%; gia tr mat o t thong namtrong pham vi B = 1,4T en B = 1,6T . ay la dang la thep dan t nh hng.Vidang la thep nay mach t c cau tao theo hnh dang ac biet : hnh xuyen . .va khong thuoc dang E, I.

BC 3 :Xac nh s o nguyen ly cua may bien ap ; tnh toan so vong day quan

.

Theo ly thuyet so vong day quan cua cac cuon day may bien ap cxac nh theo sc ien ong cam ng trong cac bo day s va th cap (xem lai Lythuyet May bien ap); Trong khi o theo s o nguyen ly may bien ap can thchien, chung ta ch co c cac thong so ien ap nh mc cua cac bo day.

Goi U1 ; U2 lan lt la cac ien ap cua day quan s va th cap bien ap,chung ta co the tnh toan so vong day quan bien ap theo quan he (1.5) va (1.6)khi thc hien thi cong.

1v1 U.nN = (1.5)

2v2 U.n).1,105,1(N = (1.6)

Trong o:N1 , N2 lan lt la so vong day quan s cap, va th cap cua bien apTrong quan he (1.6) khoang gia tr ( 1,05 1,1) c xem la t so chenh

lech gia sc ien ong tai day quan th cap so vi ien ap nh mc tai th capluc ay tai.CHU Y: Trong cac bai toan tnh chnh xac t so chenh lech nay c xac nhtheo cac bang so thong ke chon trc. T so nay phu thuoc vao cap congsuat cua bien ap.


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BC 4 : Chon mat o dong ien, c lng hieu suat, chon gia tr he so lap ay tnhtoan ng knh day quan s va th cap.

Trong bc 4, chung ta tien hanh tuan t cac cong oan tnh toan sau:

Chon mat o dong ien J qua day quan may bien ap. Gia tr mat o

dong ien theo ly thuyet thiet kephu thuoc vao cac thong so sau : Cap cach ienchu nhiet cua vat lieu dung thi cong bo day bien ap, che o lam viec may bienap lien tuc, ngan han lap lai hay ngan han khong lap lai. . .; kieu thong gio giainhiet cho day quan bien ap ..

Muon chon gia tr mat o dong chnh xac, chung ta can tham khao cacbang so tieu chuan.

Trong bai thc tap nay, chung ta chon mat o dong cho day quan maybien ap trong pham vi : J = 4 A/mm2 en 5 A/mm2.

Tnh toan dien tch cua ca so loi thep; goi Acs la dien tch ca so; chungta co quan he sau:

hcAcs .= (1.7)Trong o:[ Acs ] = [mm2] ; [a] = [b] = [ mm]

Vi la thep tieu chuan, chung ta co quan he gia cac kch thc c bana, b vi kch thc ca so loi thep nh sau:

2

.3;2

ah

ac ==

(1.8)Nh vay, chung ta co the xac nh dien tch ca so loi thep theo quan he

khac nh sau :2

2.75,0

43

aa

Acs == (1.9)

Goi Kl la he so lap ay ca so loi thep; Kl c nh ngha nh sau:

theploisocadienTiet

capthvasquandaydientietTongKl = (1.10)

Gia tr nay theo thi cong c xac nh trong pham vi sau : Kl = 0,36 0,46

Goi la hieu suat cua may bien ap; theo ly thuyet may bien ap, vi maybien ap la dang mot pha, chung ta nh nga hieu suat theo quan he sau:

111

222

1

2

cos.I.Ucos.I.U

capsvaocapcungdungtacsuatCongtaitrenthutieudungtacsuatCong

PP

=== (1.11)

Trong cac trng hp tai co tnh cam, ong thi neu xem nh ton hao theprat be, ien khang tan t cua bien ap khong cao; luc o gia tr he so cong suat taiva he so cong suat pha s cap co the xem nh gan bang nhau.


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Trong trng hp nay, mot cach gan ung chung ta co the viet nh sau:

1

2

11

22

111

222

1

2

SS

I.UI.U

cos.I.Ucos.I.U

PP

=== (1.12)

Trong o:

S1 va S2 : lan lt la cong suat bieu kien cung cap vao pha s cap va thcap. Neu ap dung quan he (1.12) chung ta co the xac nh c t so gia tr dongien qua cac day quan s va th cap, xem quan he (1.13).

2

1

1

2

UU.

II = (1.13)

Vi gia tr mat o dong ien J chon trong cac cong oan tnh toan tren,chung ta suy ra t so tietdien cua day quan s cap va th cap t quan he (1.13 ).

Theo ly thuyet ta co : [ ][ ]2mm/A

AJIs ==

Goi s1 ; s2 la tiet dien day quan s cap va th cap, suy ra:

2

1

221

22

2

1

1

2

1

2

dd

4d.4d.

UU.

II

ss

=

===

Tom lai, ta co quan he sau:

2

1

1

2

UU.

dd =

hay

2

1

1

2

UU.

ss = (1.14)

Trong o:d1 ; d2 la ng knh day tran pha s cap va th cap.

Vi day quan s va th cap la day ien t tiet dien tron trang men,ng knh day co tnh lp men boc va ng kng day tran quan he vi nhau nh

sau ay: [ ] [ ] mm05,0mmdmmdc += (1.15)CHU Y:

Trong qua trnh tnh toan bien ap chung ta can phan biet cac khainiem sau ay:

Da theo cac gia tr dong ien tai qua day quan va mat o dong ien,chung ta xac nh c tiet dien day , va ng knh day tran.

Da theo tiet dien day va ng knh day co lp men boc, chung ta se xacnh c he so lap ay ca so loi thep.

Tuy nhien quan he (1.15) ch ung cho cac loai day ien t co ng knhln hn 0,2mm; vi ng knh day nho hn be day lp men giam thap


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Trong qua trnh tnh toan c lng thi cong, chung ta co the tnh t sochenh lech gia tiet dien day quan tran va tiet dien day quan khi tnh luon lpcach ien theo quan he (1.16) sau ay. Quan he nay hoan toan chnh xac khiday quan tiet dien tron va lp men boc day 0,05mm ong thi ng knh dayquan thay oi trong pham vi t 0,25mm en 1mm.

( )1,144,1s

sc = (1.16)

Trong o;sc , va s lan lt la tiet dien day quan co tnh lp men boc cach ien va

tiet dien day tran. Ngoai ra chung ta chu y; khi ng knh day co gia tr be t sotiet dien chenh lech co gia tr ln.

Trong qua trnh tnh toan c lng s bo, chung ta co the lap quan he sauay e loai bo anh hng chenh lech gia tr gia s va sc .

2

1

1

2

c1

c2

UU.

ss

ss = (1.17)

Phoi hp cac quan he va trnh bay: (1.5); (1.6); (1.7); (1.10); (1.14); va(1.16) ta co:

cs

c22c11l A

s.Ns.NK += (1.18)

Trong o n v o cua cac tiet dien tnh theo [mm2

]. Chon gia tr Kl = 0,46chung ta thanh lap c he phng trnh sau dung xacnh tiet dien day quan sva th cap (co tnh luon lp men boc cach ien).

=

=+

2

1c1c2

cslc22c11

UU..ss

A.Ks.Ns.N

(1.19)

Giai he thong phng trnh tren chung ta suy ra : tiet dien day quan (co tnh

en be day cach ien) cua day quan s va th cap; ng knh day co cachien va ng knh day tran.

CHU Y:Khi tnh c cac gia tr ng knh day quan, chung ta phai chnh tron

so cac gia tr tnh c theo ung cac kch thc san co, qui nh do cacnha san xuat.

Qua trnh chnh nay phai kheo leo ekhong lam gia tang he so lap ay(a en thc trang khong bo lot bo day vao ca so loi thep); nhng cung

khong c lam giam qua thap gia tr Kl ( tranh tnh trang lam giam thapcong suat bien ap , khong tan dung kch thc san co cua loi thep ) .


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BC 5 : c lng cong suat bieu kien nhan c pha th cap bien ap.

Vi cac ket qua tnh c trong bc 4, da vao gia tr tiet dien day tran s va th cap, gia tr mat o dong ien a chon, chung ta tnh dong ien nhmc qua day quan khi mang ay tai (tai ung nh mc).

11 s.JI = 212 s.JI = (1.20)

Can c vao gia tr dong ien tnh c, chung ta xac nh cong suat bieukien cung cap t th cap en tai.

222 I.US = (1.21)

BC 6 : Tnh toan so vong day quan mot lp, so lp cua bo day quan s va th cap.

Trong qua trnh thi cong, so vong mot lp day quan va so lp day quanthc hien c tren bo day; phu thuoc vao cac yeu to sau:

Kch thc va vat lieu lam khuon quan day . Be day giay cach ien lp gia cac lp day quan.

Vi khuon quan day, chung ta co the la chon theo cac phng an sau:

PHNG AN DUNG KHUON NHA UC SAN :

Chung ta co the dung khuon nha uc san, khi kch thc khuon tngthch vi kch thc loi thep. Chon theo phng an nay, khong ton thi gian lamkhuon, nhng phai thc hien cong tac chuan b lam sach cac canh khuon nhatrc khi quan day.

V kha nang chu nhiet cua khuon nha khong cao so vi cac loai vat lieucac ien khac: bakelite, carton cach ien, giay presspahn. .. ong thi e tao dedang trong qua trnh che tao be day cua khuon nha thng bang hay ln hn1mm; nh vay be cao hieu dung dung rai day quan se nho hn be cao ca so loithep lam giam thap so vong day quan bo tr cho moi lp.

ieu cuoi cung can quan tam khi chon la khuon la chu y en be day bcua loi thep. Gia tr be day loi thep, xac nh trong qua trnh tnh toan so vongday, se nho hn be day loi thep bien ap thc te. S kien nay xay ra do ba v cac canh moi la thep; lam tang o day cua loi thep trong qua trnh lap ghep(cong nghe dap la thep cang chnh xac va tinh vi lam giam thap lp ba v xuathien tren cac canh cua la thep).

Tom lai trong qua trnh thi cong, trc khi thi cong: chung ta nen ghep toanbo cac la thep vao khuon nha e xac nh kha nang cha cua khuon. Neukhuon qua rong so vi be day la thep, de sinh ra hien tng rung va tieng on tanso thap khi bien ap van hanh. Ngc lai neu khuon qua hep, chung ta khong theghep het toan bo la thep vao khuon, nh vay so lieu tnh toan se sai lech.


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V tr cac canh canlam sach trc khithi cong quan day

V tr cac canhcan lam sachtrc khi thi

cong quan day

Cac la thep E cua loi thepghep vao khuon quan day

Phng phap ghep la thepE vao khuon quan day

HNH 1.3 : Khuon nha dung quan day va phng phap ghep loi thep th khuon.

hHhd

HNH 1.4: Be cao hieu dung quan day.

Khi tnh toan so vong mot lp day quan, be cao quan day xac nh theokch thc a tr i be day cua khuon quan (phan khuon che pha tren 2 mat cuabo day) . Goi be cao dung quan day la be cao hieu dung Hhd , ta co:

)dayquankhuondaybe.(2hHhd = (1.22)

PHNG AN GIA CONG KHUON QUAN DAY BANG GIAY CACH IEN :Khi dung giay cach ien lam khuon quan day bien ap, ta phai chon giay

cach co o day khoang 1mm (neu khuon 1 lp) hoac 0,5mm (khi thc hienkhuon co 2 lp). Giay cach ien lam khuon phai cng , co o ben c hoc.

Trong hnh 1.3chung ta trnh bay hnhdang khuon nha, cac

v tr canh can lam sachtrc khi thi cong, cachghep th loi thep vaokhuon nha trc khi thicong. Kch thc cuakhuon dung quan dayc trnh bay tronghnh 1.4.


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a'

h

b'

LOI GO GIAY CACH IEN DUNG LAM KHUON

ha' a'b' b' a'

Phan giayc cat bo

ng gapc'

GIAY CACH IEN DUNGLAM KHUON(Sau khi a cat bo cac

dien tch khong can thiet)

PHNG PHAP GAPGIAY CACH IEN

BOC QUANH LOI GO

PHNG PHAP LONGTAM CACH IEN

CHE CANH DAY QUAN

KHUON QUAN DAY LAMBANG GIAY CACH IENTHC HIEN HOAN CHNH

HNH 1.5 : Phng phap thc hien khuon quan day bang giay cach ien.


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Trong hnh 1.5 trnh bay trnh t thc hien khuon quan day lam bang giaycach ien. Vi phng phap lam khuon quan day bang giay cach ien; khi thchien chung ta can chu y en cac ac iem sau:

Loi go phai co kch thc quan he vi kch thc loi thep nh sau: Kch thc a loi go hi ln hn kch thc a cua la thep khoang 0,5 mm. Kch thc b loi go ln hn kch thc toan bo cac la thep E ghep sat lai;

kch thc nay ln hn kch thc b dung tnh toan tiet dien loi thep. Kch thc h cua loi go bang o cao h cua ca so loi thep.

Be rong cua tam giay cach ien dung lam tai cua khuon quay daydung che cac canh day quan chong xay xat vi la thep trong qua trnh lap ghepphai co be rong bang vi be rong c cua ca so loi thep.

Phai dung keo dan lp giay gap m cua khuon quan day. Lp gap mluon nam pha canh a cua loi thep.

Dung keo dan nh v cac tam giay cach ien (tai cua khuon quan)vao khuon quan day.

Sau khi thc hien; ch cho cac lp keo dan kho han, cho loi go thoatkhoi khuon giay va dung la thep E m kiem tra lai ieu kien bo lot la thep E vaokhuon quan day. Neu can thiet dung keo ta nh hnh nhng v tr d tha. Sau khicho la thep E vao khuon kiem tra o cao cua khuon phai bang hay hi thap hn

be cao h cua ca so loi thep (xem hnh 1.6).

HNG TAC ONG THOAT LOI GO KHOIKHUON QUAN DAY

HNH 1.6: Thoat loi go va m th la thep E vao khuon quan day.


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Da vao kch thc khuon chung ta xac nh so vong cho moi lp dayquan va be day tnh toan cho bo day quan.

So vong day quan cho mot lp day quan s cap:

quanc1

hd1 K.d

Hlp/SV = (1.23)

Trong o:Kquan : la he so quan phu thuoc vao cong nghe quan day, gia tr nay c

xac nh trong pham vi : Kquan = (0,95 en 0,92 ).

So vong day quan cho mot lp day quan th cap:

quanc2

hd

2K.

d

Hlp/SV = (1.24)

So lp day quan s cap :

lp/SVNSL

1

11 = (1.25)

So lp day quan th cap :

lp/SVNSL

2

22 = (1.26)

Be day cuon day quan :

)ed.(SL)ed.(SLe 2cc221cc11 +++= (1.27)Trong o:e : be day cuon day quan, co tnh luon cach ien gia cac lp day quan.e

c1: be day giay cach ien lp gia cac lp day quan s cap.

ec2 : be day giay cach ien lp gia cac lp day quan th cap.

Thong thng, vi may bien ap 1 pha cong suat di 50VA, day quan scap co the quan khong can cach ien lp, e tranh lam tang be day cuon daydo giay cach ien lp tao ra. Ch can cach ien lp gia day quan s cap va thcap. Vi cong nghe nay, khi thi cong can rai eu so vong day tren moi lp trongqua trnh quan day; ong thi phai tam cach ien that ky. Vi cac bien ap cocong suat ln hn t 100VA tr len, chung ta nen dung cach ien gia cac lptrong moi cuon day; be day cach ien lp phu thuoc vao khoang ien ap chenh

lech gia hai lp day quan. Neu ien ap chenh lech gia hai lp khong qua 600V,chung ta co the chon giay presspahhn o day cach ien khoang 0,1mm.


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Kiem tra lai he so lap ay tnh theo be day choan cho cua cuon day sovi be rong ca so loi thep.

Trong trng hp nay, neu khong e y en be day cua khuon quan day,chung ta co he so lap ay ca so loi thep tnh theo be day choan cho cua cuonday quan bien ap nh sau:

ceK lcs= (1.28)

Gia tr cho phep cua he soKlcs = ( 0,75 0,82 ). Neu gia tr tnh toan cnho hn khoang gia tr cho phep, chung ta cha tan dung het kha nang cua loithep; ngc lai neu gia tr tnh toan c ln hn khoang gia tr cho phep nay,cuon day co kha nang khong bo lot vao ca so.

en giai oan nay neu cac so lieu tnh toan a thoa, chung ta tien hanh

thc hien sang phan thi cong quan day bien ap (Thc tap sang bai 2).

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Hd Thuctap Quanday-bai 1