BI GING KH C IN

CHNG 6 :

R LE IU KHIN V BO V

B CNG THNG

TRNG I HC CNG NGHIP TP.HCM

KHOA IN

R-le l loi kh c in dng t ng ng ct mch

iu khin , bo v v iu khin s lm vic ca mch

in.

C nhiu cch phn loi r le:

Phn loi theo nguyn l lm vic c:

R-le in t.

R-le in ng.

R-le t in.

R-le cm ng.

R-le nhit..

KHI QUT V PHN LOI

Phn loi theo vai tr v i lng tc ng ca r-le c:

R-le trung gian.

R-le thi gian.

R-le nhit.

R-le tc .

R-le dng in.

R-le in p.

R-le cng sut.

R-le tng tr.

R-le tn s

KHI QUT V PHN LOI

Phn loi theo dng in c:

R-le dng in mt chiu.

R-le dng in xoay chiu.

Phn loi theo gi tr v chiu ca i lng i vo r-

le:

R-le cc i.

R-le cc tiu.

R-le sai lch.

R-le hng

KHI QUT V PHN LOI

R le trung gian:

R-le trung gian l kh c in dng trong cc s bo v

cc h thng in, h thng iu khin t ng, lm vic

theo c cu kiu in t, ng vai tr iu khin trung gian

gia cc thit b iu khin (contactor, r-le thi gian).

R-le trung gian c cu to gm: mch t ca nam chm

in, h thng tip im chu dng in nh ( 5A), v bo

v v cc chn ra tip im.

MT S LOI R LE THNG DNG

Nguyn l hot ng

Khi cp in p bng gi tr in p nh mc vo hai u

cun dy r-le trung gian, lc in t ht mch t kn li,

h thng tip im chuyn i trng thi v duy tr trng

thi ny (tip im thng ng h ra,thng h ng li).

Khi ngng cp ngun, mch t h, h thng tip im tr

v trng thi ban u.

R LE TRUNG GIAN

im khc bit gia contactor v r-le trung gian ?

Trong r-le trung gian ch c tip im c kh nng chu

dng in nh (tip im thng ng v tip im thng

m), s dng cho mch iu khin v khng c h thng dp

h quang.

K hiu SPDT:

SINGLE POLE DOUBLE THROW, r-le mang k hiu

ny c mt cp tip im, gm tip im thng ng v

thng h, cp tip im ny c mt u chung.

3 5

4 1

2

SPDT

K hiu SPST:

SINGLE POLE SINGLE THROW, r-le mang k hiu

ny gm c mt tip im thng h.

4 3

1

2

SPST

K hiu DPDT:

DOUBLE POLE DOUBLE THROW, r-le mang k

hiu ny gm c hai cp tip im . Mi cp tip im

gm tip im thng ng v thng h, cp tip im

ny c mt u chung.

3 5

1

2

DPDT

6 8

4

7

K hiu DPST:

DOUBLE POLE SINGLE THROW, r-le mang k hiu

ny gm c hai tip im thng h.

4

3

1

2

DPST

6

5

Ngoi ra, cc r-le khi c lp ghp trong t iu khin

thng c lp trn cc chn ra. Ty theo s lng

chn ra ta c cc kiu khc nhau: 8 chn, 11 chn,

14 chn

L kh c in dng trong lnh vc in iu khin, in t

ng, vi vai tr iu khin trung gian gia cc thit b iu

khin theo thi gian nh trc.

Cu to gm: mch t ca nam chm in, b nh thi

gian lm bng linh kin in t, h thng tip im chu

dng in nh ( 5A), v bo v v cc chn ra tip im.

Ty theo yu cu s dng c hai loi r-le: r-le thi gian

ON DELAY, r-le thi gian OFF DELAY.

R LE THI GIAN

K hiu: TR TR

in p t vo hai u cun dy r-le thi gian c ghi trn nhn,

: 110V, 220V

H thng tip im:

TR TR

TR

TR

TR

TR

TR

TR

Thng ng :

Thng h :

Tip im tc ng c tnh thi gian:

Tip im thng m ,ng chm, m

nhanh:

Tip im thng ng ,m chm , ng

nhanh:

R LE THI GIAN ONDELAY

Khi cp ngun vo cun dy ca r-le thi gian ON

DELAY, cc tip im tc ng khng tnh thi gian

chuyn i trng thi tc thi, cc tip im tc ng c

tnh thi gian khng i. Sau khong thi gian nh

trc, cc tip im tc ng c tnh thi gian s chuyn

trng thi v duy tr trng thi ny.

Khi ngng cp ngun vo cun dy, tt c cc tip im

tc thi tr v trng thi ban u.

R LE THI GIAN ONDELAY

Sau y l s chn ca r-le thi gian ON DELAY:

2

1

3 6

4 5

7

8

source

Hnh dng c th ca r-le thi gian ON DELAY

c ph bin:

Khi cp ngun vo cun dy ca r-le thi gian OFF

DELAY, cc tip im tc ng tc thi v duy tr trng

thi ny.

Khi ngng cp ngun vo cun dy, tt c cc tip im

tc ng khng tnh thi gian tr v trng thi ban u.

Tip sau mt khong thi gian nh trc, cc tip

im tc ng c tnh thi gian s chuyn v trng thi

ban u.

R LE THI GIAN OFF DELAY

R le thi gian OFF DELAY:

K hiu: TR TR

in p t vo hai u cun dy r-le thi gian : 110V, 220V

TR TR

TR

TR

TR

TR

TR

TR

Thng ng :

Thng h :

Tip im tc ng c tnh thi gian:

Tip im thng m ,ng nhanh, m

chm:

Tip im thng ng ,m nhanh, ng

chm:

Sau y l s chn ca r-le thi gian OFF DELAY:

2

1

3 6

4 5

7

8

source

Khi nim :

L kh c in bo v ng c v mch in khi s c qu

ti. Thng dng km vi cng tc t.

Dng in p xoay chiu n 500v, tn s 50Hz. Mt s

kt cu mi ca rle nhit c dng nh mc n 150A,c

th dng li in 1 chiu, in p n 440V

R-le nhit khng tc ng tc thi theo tr s dng in

v n c qun tnh nhit ln, phi c thi gian pht nng,

do n lm vic c thi gian t vi giy n vi pht.

R LE NHIT (ORL)

R LE NHIT (ORL)

Nguyn l hot ng:

Da trn tc dng nhit ca dng in lm gin n phin

kim loi kp. Phin kim loi kp gm hai l kim loi c h

s gin n khc nhau ghp cht vi nhau thnh mt phin

bng phng php cn nng hoc hn. Khi c dng in

qu ti i qua, phin lng kim c t nng, un cong v

pha kim loi c h s gin n b, y cn gt lm l xo co

li v chuyn i h thng tip im ph.

r-le nhit lm vic tr li, phi i phin kim loi ngui

v ko cn reset ca r-le nhit.

Phin lng kim nhit

Tip im chnh

Tip im ph:

K hiu

OL

OL

OL

OL

hoc

Phn loi R le nhit:

Theo kt cu: r-le nhit chia thnh hai loi: kiu h v

kiu kn

Theo yu cu s dng: loi mt cc v hai cc

Theo phng thc t nng:

t nng trc tip: dng in i qua trc tip tm kim

loi kp. Loi ny c cu to n gin, nhng khi thay

i dng in nh mc phi thay i tm kim loi kp,

loi ny khng tin dng t nng

t nng gin tip: dng in i qua phn t t nng

c lp, nhit lng to ra gin tip lm tm kim loi kp

cong ln.

u im: mun thay i dng in nh mc ta ch cn

thay i phn t t nng.

Khuyt im : khi c qu ti ln, phn t t nng c th

t n nhit kh cao nhng v khng kh truyn nhit

km, nn tm kim loi cha kp tc ng m phn t t

nng b chy t.

t nng hn hp: loi ny tng i tt v va t trc

tip va t gin tip. N c tnh n nh nhit tng i

cao v c th lm vic bi s qu ti ln.

Chn la R le nhit:

c tnh c bn ca r-le nhit l quan h gia dng in ph ti

chy qua v thi gian tc ng ca n. m bo tui th lu di

ca thit b theo ng s liu k thut ca nh sn xut, cc i

tng bo v cng cn c tnh thi gian - dng in.

La chn ng r-le nhit l sao cho ng c tnh A-s ca r-le

gn st ng c tnh A-s ca i tng cn bo v. Nu chn thp

qu s khng tn dng c cng sut ca ng c in, chn cao

qu s lm gim tui th ca thit b cn bo v.

Cch chn ph hp l chn dng in nh mc ca r-le nhit bng

dng in nh mc ca ng c in cn bo v, r-le s tc ng

gi tr (1,21,3) Im.

R le nhit ca hng Merlin gerin

Chnh dng ca Rle

nhit

Ch Auto/ Hand

(A/H)

NO (Normal Open) : tip im ph thng h.

NC (Normal Close) : tip im ph thng ng

DC

CB

L1

L2L3

D

CC

K K

RN

M

K

RN NK

NT

TT

KN

T

MN

KN

KN

KT

DC

CB

L1

L2L3

D

CC

K K

RN

M

KK

RN NK

Rth

K K

K

K

Rth

Rth Y

Y

Y

31

CU HI

1) Cng dng ca rle thi gian, rle trung gian, rle nhit

2) Nguyn l cu to ca rle thi gian, rle trung gian, rle nhit

3) iu kin la chn rle nhit bo v ng c

4) Ti sao rle nhit lun i km vi Contactor? Nu khng c

Contactor rle nhit lm vic c khng? Gii thch ?

5) Trong mt s iu kin mi trng thp, rle nhit khng thc hin

c, nu gii php bo v qu ti ng c trong trng hp ny ?

6) Trong rle nhit 3 pha, c hai l lng kim nhit trn hai pha, gii

thch v sao ch s dng hai l lng kim m khng s dng ba l.

7) Nt reset trn rle nhit c 2 ch : A v H. hai ch ny c

ngha nh th no? khi no s dng ch A, khi no s dng ch

H, gii thch ?

8) Phn bit Rle thi gian On Delay vi Rle thi gian Off Delay

9) Phn bit Contactor in t v rle trung gian