Bai 4 Cac Phuong Phap Khoi Dong Dong Co Ba Pha

BI 3: CC PHNG PHP KHI NG NG C 3 PHANI DUNG BI HC1. 2. 3. 4. 5. 6. 7. 8. 9. GII THIU CHUNG KHI NG TRC TiP B KHI NG KIU SAO TAM GIC B KHI NG KIU IN TR S CP B KHI NG KIU BIN TH T NG B KHI NG KiU IN TR TH CP B KHI NG BNG VAN BN DN VN KHI NG C TI KT LUNNUE046 - Alternating Current Machines

BI 3: CC PHNG PHP KHI NG1. GII THIU CHUNG 1.1. C S CA DNG KHI NGKhi mt ng c ln c khi ng, du no la ng c mt chiu hay xoay chiu se s dng mt dng in ln cung cp mt m men quay ln co th quay phn tai kt ni vi no. Dong in nay lam cho li in co th st ap anh hng h thng li in cp va c th la nguyn nhn pha hong phn ai truyn ca ng c, Vi vic s dng b khi ng ng c, ta co th giam thiu dong khi ng ln ca ng c gy ra.NUE046 - Alternating Current Machines

BI 3: CC PHNG PHP KHI NG2. KHI NG TRC TIP 2.1. S

Mch ng lcN Contactor 3-phase Motor

L1L2

L3 Motor Circuit Breaker Thermal Overload UnitNUE046 - Alternating Current Machines


Mch iu khinA Overload Contact Start Button Contactor N Coil

Control Circuit Breaker

Stop Button Hold-in Contact NUE046 - Alternating CurrentMachines


S mch

NUE046 - Alternating Current Machines

c tnh ng c 3 phaCurrent - Speed

c tnh ng c 3 pha

Speed - Torque

BI 3: CC PHNG PHP KHI NG2. KHI NG TRC TIP 2.2. GII THCH

S mchNhn nut Start khi ng. Cun ht Contactor MC/4 c ong in lam cho cac tip im MC.1, MC.2 va MC.3 ong. ng c hoat ng. Cng tc gi MC.4 cung c ong cho phep nut khi ng co th c nha ra v vi tr ban u Nhn nut Start khi ng. Cun ht Contactor MC/4 c ong in lam cho cac tip im MC.1, MC.2 va MC.3 ong. ng c hoat ng. Cng tc gi MC.4 cung c ong cho phep nut khi ng co th c nha ra v vi tr ban uNUE046 - Alternating Current Machines

BI 3: CC PHNG PHP KHI NG2. KHI NG TRC TIP 2.3. NG DNGu im -To c Moment quay khi ng ln -n gin v tng i r tin so vi cc phng php khc Khuyt im -Dong khi ng ln, nguyn nhn chinh gy hin tng sut ap trn li in -Co th lam nhiu h thng ngun cp -Gy sc lc trn khung, truc va b truyn ng cua ng c -Xut hin lc c hoc vao trong dy qun cua ng c ng dung - Trong cac ng dung co lc quan tinh nho nh la: bm ly tm, tin, may khoan cn, may mai, NUE046 - Alternating Current Machines

BI 3: CC PHNG PHP KHI NG3. KHI NG SAO/TAM GIC 3.1. S

Mch ng lcL1 L2

Line Contacto r

6-terminal Cu u ni

STAR Contacto r

L3

Overload Unit

Interlock DELTA NUE046 - Alternating Current Khoa lin ng Contactor Machines

BI 3: CC PHNG PHP KHI NG3. KHI NG SAO/TAM GIC 3.1. S

Mch iu khinContactor chnh

Timer

Star OFF Timer Contacts Delta ONInterlock ContactsNUE046 - Alternating Current Machines

KM Star

KM Delta

Hot ng mch iu khinStar-Delta Starter - Control

Line Timer

Star DeltaElectrical - Department

Hoat ng mach iu khinStar-Delta Starter - ControlLine Timer

Star Delta Motor starts in STAR

Hoat ng mach iu khinStar-Delta Starter - ControlLine Timer

Star DeltaElectrical - Department

Hoat ng mach iu khinStar-Delta Starter - ControlLine

Timer

Star

Delta

Electrical - in DELTA Motor runsDepartment

HOT NG MCH NG LC.Star-Delta Starter - PowerLine ContactorL1 L2

6-terminal Motor

STAR Contactor

L3

Overload Unit DELTA Contactor

Mechanical InterlockElectrical - Department

Hoat ng mach ng lcStar-Delta Starter - PowerL1 L2

L3

Contactor CHNH v SAO ong

ng c khi ng kiu ni sao

Contator tam giac m. Electrical - Department

Hoat ng mach ng lcStar-Delta Starter - Power

L1 L2

L3

Contactor Chnh v Tam gic ong ng c khi ng kiu ni tam gic Contator sao m.

3-phase Motor StartersStar-Delta Starter




Dong in tng ln theo ng c tnh khi ng.

Dong in giam xung gia tri inh mc theo ng c tnh khi ng trc tip

K M saom, KM tam giac ong, C tip tc khi ng ch ni tam giac

{


Qua m

Transition Surge

ng c h mach

{


Khi KM tam giac ong, m men tng ln gia tri ca khi ng trc tip

M men sao = 1/3 m men tam gic


M qua co ngha la tai thi im o ng c h mach, khng ni vi ngunKt qua la tao ra dong ln va m men tng ln.


Hu ht cc b khi ng bng cch gim in p l khng ngt ng c khi chuyn i, gi nguyn dng v m menB khi ng o gi la Qua ong

BI 3: CC PHNG PHP KHI NG3. KHI NG BNG I NI SAO/TAM GIC 3.3. NG DNGu im Gim dong khi ng gim i mt phn ba so vi phng php khi ng trc tip D.O.L. Chi khng t hn khi so sanh vi cac phng phap khi ng lam gim in ap khac Khuyt im Lam gim m men khi ng i mt phn ba so vi m men u ti, iu nay cho phep s dung phng phap nay khi ng ng c vi ch ti trong nho Xut hin nhiu trn ng dy khi chinh li t ch Sao thanh Tam giac (Loi chuyn h) ng dung S dung phng phap nay khi ng ng c di ch NUE046 Alternating Current khng ti nh la bm, cac may-Machines nghanh g trong

BI 3: CC PHNG PHP KHI NG4. KHI NG DNG IN TR S CPPrimary Resistance Starter B khi ng dung in tr s cp Thm vo phn tnh b in tr khi khi ng.

Khi ng c hoat ng se loai dn in tr cho n khi ht..NUE046 - Alternating Current Machines

BI 3: CC PHNG PHP KHI NG4. KHI NG DNG IN TR S CP 4.1. S

Mch ng lcN L1 L2 L3 Circuit Breaker Contactor chnh

in tr gii han dong

Thermal Overload Unit

3-phase Motor

Khi khi ng, cc in tr mc ni tip vi cc cun dy ng c. NUE046 - Alternating CurrentMachines

Primary Resistance Starter B khi ng dung in tr s cpN L1 L2 L3

Contactor chnh

in tr gii han dng

3-phase Motor

Circuit Breaker


Khi chy, Contator s ngt in tr ra khi mch .

Contactor chay

BI 3: CC PHNG PHP KHI NG4. KHI NG DNG IN TR S CP 4.1. S

Mch iu khinA N Line

Timer

Run


Primary Resistance Starter B khi ng dung in tr s cpContactor chnh in tr gii han dong

N L1 L2 L3

3-phase Motor

Circuit Breaker Circuit Breaker closed


Contactor chay

Primary Resistance Starter B khi ng dung in tr s cpin tr gii han dong 3-phase Motor

N L1 L2 L3

Line Contactor

As motor Line Contactor Closed. Motor starts with current reduced Motor accelerates smoothly Resistor resistors by series voltage drop decreases motor voltage steadily rises Motor voltage rises

Thermal Motor Overload Circuit rises, speed Breakercurrent falls Unit

Khi chuyn i, in p ng c gn ti in p nh mc.Run Contactor

Primary Resistance Starter B khi ng dung in tr s cpN L1 L2 L3

Line Contactor

Current-Limiting Resistances

3-phase Motor

Motor Circuit Breaker


Contactor chay ong. ng c gi nguyn u ni ng c (qua vi in vi ngun chay ong)ap inh mc.

Run Contactor

Primary Resistance Starter B khi ng dung in tr s cp

A

N Line

TimerRun


A

N Line

TimerRun


N L1 L2 L3

Line Contactor

Current-Limiting Resistances

3-phase Motor



Run Contactor

Primary Resistance Starter B khi ng dung in tr s cp B khi ng vi in tr s cp dng loi in tr lng tt hn l loi in tr kim loi. Dng in ng c chy qua in tr s lm nhit in tr tng ln, gim gi tr in tr, gim in p trn in tr, => in p ng c tng ln. Dung dch in phn ny c lin quan n dung dch kim. Nng ca dung dch ph thuc vo dng khi ng ca ng c.

BI 3: CC PHNG PHP KHI NG4. KHI NG DNG IN TR S CP 4.4. NG DNGu im Gim dong khi ng (phu thuc vao in ap ri qua cac in tr) Tng tc trn tru khi tc tng dn Khuyt im M men khi ng nho (phu thuc vao in ap ri qua cac in tr) Hiu sut thp, vi mt nhiu nng lng trong cac in tr luc khi ng t tin Dong khi ng ln hn so vi phng phap Sao/Tam giac ng dung NUE046 - Alternating Current - Qut, bm ly tm, Machines

BI 3: CC PHNG PHP KHI NG5. KHI NG DNG BIN P T NGThng qua BATN se giam in ap cp vao cun dy ng c khi khi ng.

Khi ng c at tc , bin ap se c ct ra khoi mach in.


Autotransformer Starter

Mach ng lcN L1 Line Contactor L2 3-phase Motor L3 Autotransformer

CB

O.L

ContactorChay

Contactor ni sao BA

Autotransformer Starter

Khi ng bng bin ap t nguAutotransformer N L1

Contactor chnh

BA T ngu 3-phase Motor

L2L3

CB


Contactor ni sao BA

Cac b khi ngAutotransformer Starter Khi khi ng,khi ng vi in p nh hn nh ng c Contactor chnh v ni sao BA ng N Line mc thng quaAutotransformer bin pContactorL1 3-phase Motor

L2

L3

CB


Contactor ni sao BA

Cac b khi ngAutotransformer Starterng c tng tc gian, contactor ni sao BA m Sau 1 thi vi in p gimN Line Contactor L1 3-phase Motor Autotransformer

L2

L3

CB


Contactor ni sao BA

Cac b khi ngAutotransformer StarterDong in ng c c gi nguyn thng qua ng c gi nguyn u ni vi ngun tr khang BAN Line Contactor L1 3-phase Motor Autotransformer

L2

L3

CB


Contactor ni sao BA

Cac b khi ngAutotransformer StarterN

Lc ny, ng c c nichy ng, BA c ni Sau 1 thi gian, contactor trc tip vi ngun Line tt. AutotransformerContactor3-phase Motor

L1

L2

L3 CB Thermal Overload Unit

Contactor chay

Contactor ni sao BA

Mach iu khin Control Circuit

CB

T.O/L

Stop

Start

K1M

Contactor chnhTimer

K1M

K4T K3M

K4T.1

K2M

Contactor ni sao BA

K4T.1

K2M

K3M

Contactor chy

Cac b khi ngAutotransformer Starter Control CircuitCB T.O/L Stop Start K1M

Contactor chnhTimer

K1M

K4T

(CB closed) When Start is pressed, Line (K1M),, Transformer Star (K2M) contactors and Timer (K4T) energise.

K4T.1

K3M

K2M

Contactor ni sao BA

K4T.2

K2MInterlock OPENS

K3M

Contactor chy

Cac b khi ngAutotransformer Starter Control CircuitCB T.O/L Stop Start K1M

Contactor chnhTimer

K1M

K4T K3M

Khi r le thi gian tac ng, contactor ni sao m, contactor chay ong lai

K4T.1

K2M

Contactor ni sao BA

K4T.1

K2M

K3M

Contactor chy

Interlock OPENS

Cac b khi ngAutotransformer Starter

Mt s t l ca may bin ap : 80% , 60%, 50% Dong khi ng ca ng c:

I Motor I DOL ratioI Line I DOL ratio2

T l MBA

Dong khi ng ca ngun cung cp :

Cac b khi ngAutotransformer Starter

Dong in va m men ng c c gi tng i cao.

BI 3: CC PHNG PHP KHI NG5. KHI NG DNG IN TR S CP 5.4. NG DNGu im Cung cp la chn cc gi tr m men quay khi ng C th khi ng ng c chy vi ti trng tng i nng C mt di la chn cc in p Khuyt im

Cc chi ph lc u cho cc thit b bn ngoi rt tng dung Bm thy lc, Bng ti,... - Alternating Current NUE046Machines

BI 3: CC PHNG PHP KHI NG6. KHI NG DNG IN TR TH CP

Stator

Chi than se tip xuc vi c gop tao dong in chay bn trong cun dy. Cac cun dy c ni sao vaNUE046 ra c gop. a - Alternating CurrentMachines

Rotor dy qun

Cac b khi ngSecondary Resistance Starter Dung in tr ph cho Rotor. Cun dy Stator ni trc tip vi ngun. Dung b in tr ph thm vao cun dy Rotor Khi ng c chay, in tr ph se c loai bt dn cho ti ht.


Cac b khi ngSecondary Resistance Starter Cun dy Stator ni trc tip vi ngun.N L1 L2

Line Contactor

3-phase Motor

L3


Thermal Overload UnitNUE046 - Alternating Current Machines

Secondary Resistance StarterPower Circuit Starting Mach ng lcContactor chnhN L1 L2

Motor

in tr ph bn ngoi

L3

CB

O.L

NI VI C GP.


Secondary Resistance Starter Power Circuit Accelerating Khi ng Tng tcin tr ph bn ngoi

N L1 L2 L3

Contactor chnh

Motor

CB

O.L

Step 2

Step 1

Contactor tng tcNUE046 - Alternating Current Machines

Secondary Resistance Starter Control CircuitCB T.O/L Stop Start K1M Line Contactor Step 1 Timer

K1M

K4T

K4T

K2M

Step 1 Contactor

K5T

Step 2 Timer Step 2 Contactor

K5T

K3M


Squirrel Cage / Wound Rotor

So sanh m men khi ng gia C rotor lng soc va dy qun

Double (High/Low) Standard Wound Rotor Squirrel Cage


Cac b khi ngSecondary Resistance Starter Speed / Torque Acceleration


Tng kt phn cac b khi ng Co 3 loai khi ng ng c Khi ng trc tip Gim in p khi khi ng Khi ng dng in tr phNUE046 - Alternating Current Machines

Giam in ap khi khi ng Sao tam gic Dung in tr s cp Dung bin ap t ngu Dung in tr ph vao mach Rotor


u khuyt im ca cac b khi ng. Khi ng trc tip u im: M men m my ln nht m gin v tng i re tin so vi cc phng php khi ng khc

Khuyt im: Dng khi ng ln nh hng ti cc phn c kh nh hng ti cc ph ti khc v ngun cung cpNUE046 - Alternating Current Machines

Khi ng Sao Tam gic u im: Gim dng khi ng xung cn 1/3 dng khi ng trc tip Tng i re tin

Khuyt im: M men khi ng gim cn 1/3 Ch khi ng mang ti trc tip cho ti nh

ng dng: dng cho cc ng c khi ngkhng ti hoc ti nh ( qut gi, my ca..v.v)NUE046 - Alternating Current Machines

Khi ng dung in tr s cp u im: Gim dng khi ng Tng tc m

Khuyt im M men khi ng thp Tn tht cng sut trn in tr t tin

ng dng : qut bm.v..v


Phng phap khi ng ng c dung bin ap t ngu u im Cung cp la chn cc gi tr m men quay khi ng C th khi ng ng c chy vi ti trng tng i nng C mt di la chn cc in p


Phng phap khi ng ng c dung bin ap t ngu Nhc im: Cc chi ph lc u cho cc thit b bn ngoi rt t ng dng: Bm thy lc, Bng ti,...


BI 3: CC PHNG PHP KHI NG6. KHI NG DNG IN TR TH CP 6.4. NG DNGu im c tnh k thut m men khi ng hon ho Tng tc trn trong sut qu trinh khi ng Kh nng khi ng ng c vi ti trong ban u ln Khuyt im Yu cu thm cc cng tc bo tri bo dng u t ban u ln ng dung -Dng cho cc ti c qun tnh ln nh l my nen, my ct t,


BI 3: CC PHNG PHP KHI NG7. B KHI NG DNG VAN BN DNTham kho thm t sach bai hoc


BI 3: CC PHNG PHP KHI NG8. KT LUN

C 3 loai khi ng ng c Khi ng trc tip Gim in p khi khi ng Khi ng dng in tr phNUE046 - Alternating Current Machines

Giam in ap khi khi ng Sao tam gic Dung in tr s cp Dung bin ap t ngu Dung in tr ph vao mach Rotor


Bai 4 Cac Phuong Phap Khoi Dong Dong Co Ba Pha

Documents

phu thuc vao

thermal overload

bm ly tm

cho cc thit

mt phn ba

alternating

khi ng kiu

primary resistance