Giáo trình đo lường điện - Phần 1

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(2)

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B͡môn Cung C̭SĈL͏n Trang 5

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Nguyên nhân:

(4)

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B͡môn Cung CSLn Trang 9 &ặ8+,9ơ%ơ,73

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(7)

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(8)

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.KӕLFKӍWKӏ 2.1.2 Nguyên lý:

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(9)

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+ Lò xRÿӕLNKiQJNLӇPVRiWKRһFGk\WUHRFyQKLӋPYөNpRNLPFKӍWKӏYӅYӏWUt EDQÿҫXÿLӇPYjNLӇPVRiWVӵTXD\FӫDNLPFKӍWKӏ

2.2.3 6ѫÿӗQJX\rQOê

1JX\rQOêKRҥWÿӝQJ.KLFyGzQJÿLӋQFҫQÿR,ÿLYjRFXӝQGk\WUrQNKXQJ TXD\VӁWiFGөQJYӟLWӯWUѭӡQJӣNKHKӣWҥRUDOӵFÿLӋQWӯ)

F = N.B.l.L (2.1)

7URQJÿy1VӕYzQJGk\TXҩQFӫDFXӝQGk\

%PұWÿӝWӯWK{QJ[X\rQTXDNKXQJGk\ /FKLӅXGjLFӫDNKXQJGk\

,FѭӡQJÿӝGzQJÿLӋQ

/ӵF ÿLӋQWӯQj\VӁVLQKUDPӝWP{PHQTXD\0q: NBILb

b F Mq

2

2 (2.2)

7URQJÿyEOjEӅUӝQJFӫDNKXQJGk\

Yj/E 6OjGLӋQWtFKFӫDNKXQJGk\

Nên: Mq= N.B.S.I (2.3)

Mômen quay làm pKҫQÿӝQJPDQJNLPÿRTXD\ÿLPӝWJyFDQjRÿyYjOz[R ÿӕLNKiQJEӏ[RҳQOҥLWҥRUDP{PHQÿӕLNKiQJ0ÿNWӹOӋYӟLJyFTXD\D

MÿN= K.D OjÿӝFӭQJFӫDOz[R

.LPFӫDFѫFҩXVӁÿӭQJOҥLNKLKDLP{PHQWUrQEҵQJQKDX

Mq= M ÿN N.B.S.I = K.D (2.4)

b

F

)µ

N

S

+uQK6ѫÿӗnguyên lý

ҩ Ӈ

I K BSN

(10)

B͡môn Cung C̭SĈL͏n Trang 13

ĈһWC = const D = C.I (2.5)

&JӑLOjÿӝQKҥ\FӫDFѫFҩXÿRWӯÿLӋQ$PP&KRELӃWGzQJÿLӋQFҫQWKLӃWFKҥ\ TXDFѫFҩXÿRÿӇNLPÿROӋFKÿѭӧF PPKD\YҥFK

.ӃWOXұQ TXDELӇXWKӭFWUrQWDWKҩ\UҵQJJyFTXD\DFӫDNLPÿRWӹOӋYӟLGzQJÿLӋQ FҫQÿRYjÿӝQKҥ\FӫDFѫFҩXÿRGzQJÿLӋQYjÿӝQKҥ\FjQJOӟQWKuJyFTXD\FjQJOӟQ

7ӯJyFDFӫDNLPWDVX\UDJLiWUӏFӫDÿҥLOѭӧQJFҫQÿR ĈһFÿLӇPYjӭQJGөQJ

DĈһFÿLӇP

- ĈӝQKҥ\FDRQrQFyWKӇÿRÿѭӧFFiFGzQJÿLӋQPӝWFKLӅXUҩWQKӓWӯ-12y10-14) - 7LrXWKөQăQJOѭӧQJÿLӋQtWQrQÿӝFKtQK[iFUҩWFDR

- &KӍÿRÿѭӧFGzQJYjiSPӝWFKLӅX

- KҧQăQJTXiWҧLNpPYuNKXQJGk\TXD\QrQFKӍTXҩQÿѭӧFGk\FӥQKӓ - &KӃWҥRNKyNKăQJLiWKjQKÿҳW

0X͙QÿRÿ˱ͫFFiFÿ̩LO˱͕QJ[RD\FKL͉XSK̫LTXDF˯F̭XQ̷QGzQJ EӬQJGөQJ

6ҧQ[XҩWFiFGөQJFөÿR

- ĈRGzQJÿLӋQPLOL$PSHPpW$PSHPpW - ĈRÿLӋQiSPLOL9{QPpW9{QPpW - ĈRÿLӋQWUӣ{PPpW

2.3.&ѫFҩXÿRNLӇXÿLӋQWӯ 2.3.1.KýKLӋX

const C

K BSN

(11)

2.3.2.6ѫÿӗFҩXWҥR

D3KҫQWƭQKJӗPFXӝQGk\SKҫQWƭQKWUzQKRһFSKҷQJNK{QJFyO}LWKpS

E3KҫQÿӝQJJӗPOiWKpSQRQKuQKEiQQJX\ӋWJҳQOӋFKWkPWUrQWUөF7UrQWUөF FzQFyOz[RÿӕLNKiQJNLPYjEӝSKұQFҧQGӏXNLӇXNK{QJNKt

2.3.3.1JX\rQOêKRҥWÿӝQJ

.KLFyGzQJÿLӋQFҫQÿR,ÿLYjRFXӝQGk\SKҫQWƭQKWKuQyVӁWUӣWKjQKPӝWQDP FKkPÿLӋQYjSKLӃQWKpSVӁEӏK~WYjRUmQK/ӵFK~WQj\WҥRUDPӝWP{PHQTXD\ WUөF

1I K

Mq (2.6)

'ѭӟLWiFGөQJFӫD0q NLPVӁTXD\PӝWJyFD/z[RVRVӁEӏ[RҳQGRÿyVLQKUD P{PHQÿӕLNKiQJWӹOӋYӟLJyFTXD\D

MÿN=K2.D (2.7)

.LPVӁQJѭQJTXD\NKLP{PHQWUrQFkQEҵQJQJKƭDOj

2

1 I

K K K

I

K

D

7KӵFUDӣYӏWUtFkQEҵQJNLPFKѭDGӯQJOҥLQJD\PjGDRÿӝQJTXDOҥL[XQJTXDQK YӏWUtÿyQKѭQJQKӡFyEӝFҧQGӏXEҵQJNK{QJNKtVӁGұSWҳWTXiWULQKGDRÿӝQJQj\

2.3.4.ĈһFÿLӇPYjӭQJGөQJ DĈһFÿLӇP

- &ҩXWҥRÿѫQJLҧQGӉFKӃWҥRJLiWKjQKUҿ - ĈRÿѭӧFÿLӋQPӝWFKLӅXYj[RD\FKLӅX

Hình 2.6: &ѫFҩXÿRNLӇXÿLӋn tӯ

1 Cuӝn dây phҫQWƭQK Trөc quay

2 Rãnh hҽp Bӝcҧn dӏu kiӇu khơng khí

3 PhiӃn thép /z[Rÿӕi kháng

6

1

3

5

(12)

B͡môn Cung C̭SĈL͏n Trang 15 - KҧQăQJTXiWҧLWӕWYuFyWKӇFKӃWҥRFXӝQGk\SKҫQWƭQKYӟLWLӃWGLӋQGk\OӟQ - 'RFXӝQGk\FyO}LOjNK{QJNKt QrQWӯWUѭӡQJ\ӃXYuYұ\ÿӝQKҥ\NpPYjFKӏX ҧQKKѭӣQJFӫDWӯWUѭӡQJQJRjL

- &ҩSFKtQK[iFWKҩS - 7KDQJFKLDNK{QJÿӅX EӬQJGөQJ

- &KӃWҥRFiFGөQJFөÿRWK{QJGөQJ9{QPpW$PSHPpWÿR$& - 'QJWURQJVҧQ[XҩWYjSKzQJWKtQJKLӋP

&ѫFҩXÿRNLӇXÿLӋQÿӝQJ 2.4.1 êKLӋX

2.4.2.6ѫÿӗFҩXWҥR

&ѫFҩXÿRÿLӋQÿӝQJ+uQKJӗPFyFXӝQGk\SKҫQWƭQKÿѭӧFFKLDWKjQK SKҫQ QӕL WLӃS QKDX ÿӇ WҥR UD Wӯ WUѭӡQJ ÿӅX NKL Fy GzQJ ÿLӋQ FKҥ\ TXD 3KҫQ ÿӝQJ Oj

Hình 2.7: Ký hiӋXFѫFҩXÿRÿLӋQÿӝng

)2

I1

I2

)1

1

2

Hình 2.8: Ký hiӋXFѫFҩXÿRÿLӋQÿӝng

1- CuӝQGk\WƭQK

2- CuӝQGk\ÿӝng

(13)

NKXQJGk\ÿһWWURQJFXӝQGk\WƭQKYjJҳQWUrQWUөFTXD\+uQKGiQJFXӝQGk\FyWKӇ WUzQKRһFYX{QJ&ҧSKҫQÿӝQJYjSKҫQWƭQKÿѭӧFEӑFNtQEҵQJPjQFKҳQWӯÿӇWUiQKҧQK KѭӣQJFӫDWӯWUѭӡQJQJRjLÿӃQVӵOjPYLӋFFӫDFѫFҩXÿR

2.4.3.Nguyên OêKRҥWÿӝQJ

.KLFyGzQJÿLӋQ,1, I2 '&KRһF$&ÿLYjRFXӝQGk\GLÿӝQJYjFӕÿӏQKVӁWҥRUD

mômen quay:

Mq= kqI1I2 GzQJÿLӋQ'&

+RһF (1 )

01

³

T

q ii dt

T kq

M GzQJÿLӋQ$&

9ұ\JyFTXD\

2 1I I k k

c q D

KRһF (1 2 )

1i dt i T k k T

c q

³

D KcOjKҵQJVӕ[RҳQFӫDOz[R

1ӃX const k

k

c

q WKuWKDQJÿRWX\ӃQWtQKWKHR,

1, I2

2.4.4.ĈһFÿLӇPYjӭQJGөQJ

&ѫ FҩX ÿR ÿLӋQ ÿӝQJ Fy WKӇ GQJ WURQJ PҥFK PӝW FKLX Yj [RD\ FKLX WKDQJ R NK{QJXFyWKGQJFKWR9{QPpW$PSHPpWYj2iWPpWFyFKtQK[iFFDRYL FSFKtQK[iFy1KFLPOjWLrXWKF{QJVXWOQ

&ặ8+,9ơ%ơ,73 $&ặ8+,&1*&%ơ,

FNFiFFkXKLFKQFkXWUOL~QJQKWYjW{HQ{mFKQYjRFWWQJ QJ

TT 1LGXQJFkXKL a b c d

2.1. &ѫFҩXÿRWӯÿLӋQÿRÿѭӧFFiFÿҥLOѭӧQJ: a ĈLӋQPӝWFKLӅX

b ĈLӋQ[RD\FKLӅX

c ĈLӋQ[RD\FKLӅXPӑLWҫQVӕ d &ҧPӝWFKLӅXOүQ[RD\FKLӅX

#ð #ð #ð #ð

2.2 &ѫFҩXÿRWӯÿLӋQWKDQJÿRÿѭӧFFKLD: a ĈӅXWX\ӃQWtQK

b 7ӹOӋWKHRKjPORJDULW

(14)

B͡môn Cung C̭SĈL͏n Trang 17 c 7ӹOӋEұF

d 7ӹOӋWKHRKjPPǊ

2.3 ĈһF ÿLӇP FKtQK FӫD ORҥL Fѫ FҩX ÿR NLӇX ÿLӋQ Wӯ NLӇX ÿLӋQÿӝQJYjNLӇXWӯÿLӋQOj

a .LӇXÿLӋQWӯ3KpSÿRFKtQK[iFYjÿӝQKҥ\FDR b .LӇXÿLӋQÿӝQJ3KpSÿRFKtQK[iFYjÿӝQKҥ\FDR c .LӇXWӯÿLӋQ3KpSÿRFKtQK[iFYjÿӝQKҥ\FDR d %DNLӇXOjQKѭQKDXNK{QJNKiFELӋW

#ð #ð #ð #ð

2.4 ĈӇPӣUӝQJJLӟLKҥQÿRFKRFѫFҩXÿRÿLӋQWӯÿӇÿRÿLӋQ

iS[RD\FKLӅXWUrQ9SKҧLGQJ:

a ĈLӋQWUӣSKөPҳFQӕLWLӃS b ĈLӋQWUӣSKөPҳFVRQJVRQJ c %LӃQiSÿROѭӡQJ

d %LӃQGzQJÿROѭӡQJ

#ð #ð #ð #ð

2.5 .KLÿRÿLӋQWUӣ*yFTXD\FӫDNLPFjQJOӟQWKuNӃWOXұQ: a ĈLӋQWUӣUҩWOӟQ

b ĈLӋQWUӣFjQJOӟQ c ĈLӋQWUӣFjQJQKӓ d 7XǤORҥLPi\ÿR

#ð #ð #ð #ð

2.6 .KLÿRÿLӋQWUӣEҵQJPi\ÿRFKӍWKӏNLP7UӏVӕSKҧLÿѭӧF

ÿӑFWUӏWӯ:

a 3KҧLTXDWUiL b TráLTXDSKҧL c *LӳDUDELrQ

d 7ҥLYӏWUtNLPGӯQJOҥL

(15)

2.7 .KL ÿR GzQJ ÿLӋQ KRһF ÿLӋQ iS *yF TXD\ FӫD NLP FjQJ OӟQWKuNӃWOXұQ

a 7UӏVӕFjQJQKӓ b 7UӏVӕQKӓUҩW c 7UӏVӕFjQJOӟQ d 7XǤORҥL

#ð #ð #ð #ð

2.8 .KLÿRGzQJÿLӋQKRһFÿLӋQiSEҵQJPi\ÿRFKӍWKӏNLP

7UӏVӕSKҧLÿѭӧFÿӑFWUӏWӯ a 3KҧLTXDWUiL

b 7UiLTXDSKҧL c *LӳDUDELrQ

#ð #ð #ð #ð

%&kXKӓL

1 1rXQJX\rQOêOjPYLӋFFӫDPi\ÿRFKӍWKӏNLPYjFiFFKLWLӃWFKXQJFӫDPi\ÿR FKӍWKӏNLP

2 1rXFҩXWҥRQJX\rQOêKRҥWÿӝQJYjÿһFÿLӇPӭQJGөQJFӫDFiFFKӍFiFFѫFҩX ÿRWӯÿLӋQÿLӋQWӯÿLӋQÿӝQJ

7+Ӵ&+¬1+48$16È71+Ұ1%,ӂ79ӄ&Ҩ87Ҥ29¬ĈҺ&Ĉ,ӆ0&Ӫ$ &È&&Ѫ&Ҩ8Ĉ27+Ӵ&+¬1+7Ҥ,/Ӟ3

1 &KRKӑFVLQKTXDQViWYjQKұQELӃWWPӝWVӕFѫFҩXÿR WKѭӡQJGQJ yêu cҫX:

- 9LӃWWrQFiFFѫFҩXÿR

- 1rXF{QJGөQJYjQJX\rQOêOjPYLӋFFӫDFiFORҥLFѫFҩXÿR ÿmÿѭӧFTXDQViW 1rXQKӳQJÿLӇPJLӕQJYjNKiFQKDXFӫDFiFFѫFҩXÿRÿmÿѭӧFTXDQViW 1rXӭQJGөQJFӫDFiFFѫFҩXÿRÿyYjRFiFORҥLGөQJFөÿR

- 3KkQORҥLFiFcѫFҩXÿR ÿmÿѭӧFTXDQViWWKHRWӯQJQKyP + Nhóm FѫFҩXÿRÿLӋQÿӝQJ

(16)

B͡mơn Cung C̭SĈL͏n Trang 19 + Nhóm FѫFҩXÿRFҧPӭQJ

/jPFiFEjLWұSWҥLOӟS %%jLWұS

1rXFiFÿӏQKQJKƭDYӅÿROѭӡQJ

3KѭѫQJSKiSÿROjJu"&yPҩ\SKѭѫQJSKiSÿR" ĈѫQYӏÿROjJu"7KӃQjRJӑLOjÿѫQYӏWLrXFKXҭQ" 'өQJFөÿROjJu"

(17)

&+ѬѪ1*,,,

Ĉ2&È&ĈҤ,/ѬӦ1*Ĉ,ӊ1&Ѫ%Ҧ1

*LӟLWKLӋX

7URQJTXiWUuQKOҳSUiSEҧRGѭӥQJVӳDFKӳDYjYұQKjQKFiFPҥFKÿLӋQKRһFKӋ WKӕQJÿLӋQÿzLKӓLQJѭӡLF{QJQKkQSKҧLQҳPÿѭӧFFiFWK{QJVӕFӫDFiFÿҥLOѭӧQJFѫ EҧQWURQJPҥFKÿLӋQPҥQJÿLӋQKRһFKӋWKӕQJÿLӋQ7ӯÿyÿѭDUDSKѭѫQJiQOҳSÿһWEҧR GѭӥQJVӱDFKӳDYjYұQKjQKPҥFKPҥQJKRһFKӋWKӕQJÿLӋQWӕLѭXQKҩWÿӗQJWKӡLÿҧP EҧRDQWRjQFKRQJѭӡLYjWKLӃWEӏ0XӕQYұ\QJѭӡLF{QJQKkQÿLӋQSKҧLQҳPÿѭӧFFiF SKѭѫQJSKiSÿRYjNLӇPWUDFiFÿҥLOѭӧQJFѫEҧQÿyPӝWFiFKQKXҫQQKX\ӉQYjFyQKѭ Yұ\PӟLQkQJFDRÿѭӧFFKҩWOѭӧQJFӫDPҥFKPҥQJÿLӋQYjKӋWKӕQJÿLӋQ

ĈRGzQJÿLӋQ

ĈRGzQJÿLӋQPӝWFKLӅX'&

D'өQJFөÿRGөQJFөÿӇÿRGzQJÿLӋQÿӑFWKҷQJQJѭӡLWDGQJ$PSHPpW êKLӋX

b.3KѭѫQJSKiSÿR .KLÿR$PSHPpWÿѭӧFPҳFQӕLWLӃSYӟLSKөWҧ,KuQK

Ta có: RWÿ= Rt + Rm 7URQJÿy

RmOjÿLӋQWUӣWURQJFӫD$PSHPpWJk\VDLVӕ

0һWNKiFNKLÿR$PSHPpWWLrXWKөPӝWOѭӧQJF{QJVXҩW

P

A

I

R

m

F0ӣUӝQJJLӟLKҥQÿRFKR$PSHPpWWӯÿLӋQ

.KLGzQJÿLӋQFҫQÿRYѭӧWTXiJLӟLKҥQÿRFӫDFѫFҩXÿRQJѭӡLWDPӣUӝQJWKDQJ ÿREҵQJFiFKPҳFQKӳQJÿLӋQWUӣVRQJVRQJYӟLFѫFҩXÿRJӑLOj6KXQWÿk\OjSKѭѫQJ SKiSSKkQPҥFK

Ta có: ISRS= IA Rm hay

S m A S

R R I

I (3.1)

Rm:ÿLӋQWUӣWURQJFӫDFѫFҩXÿR

RS: ÿLӋQWUӣFӫD6KXQW

A

I

phөtҧi A

Rt

Rm

x

U

Hình 3.1: Vѫÿӗmҳc Ampemét

-+

(18)

%͡P{Q&XQJ&̭SĈL͏Q Trang 21 7ӯWDVX\UD S S m A A S R R R I I I

Vì: I = IA+ IS OjGzQJÿLӋQFҫQÿRQrQWDFy

S m S S m A R R R R R I I (3.2) ĈһW S m i R R n Ta suy I = niIA

S m i R R n

( OjEӝLVӕFӫD6KXQW&iFKWtQKÿLӋQWUӣ6KXQW

ni: cho ELӃWNKLFyPҳF6KXQWWKuWKDQJÿRFӫD$PSHPpWÿѭӧFPӣUӝQJQiOҫQVRYӟL O~FFKѭDPҳF6KXQW

7ӯWDWKҩ\QӃX5SFjQJQKӓVRYӟL5mWKuWKDQJÿRÿѭӧFPӣUӝQJFjQJOӟQ ĈLӋQWUӣVKXQWFyWKӇWtQKWKHRFiFKVDX max tai max * A m A S I I R I R (*)

7URQJÿy,WҧLOjGzQJÿLӋQTXDWҧL i m S n R R

$PSHPpW ÿѭӧF PҳF QKLӅX ÿLӋQ WUӣ 6KXQW NKiF QKDX ÿӇ Fy QKLӅX WҫP ÿR NKiF QKDXQKѭKuQKYӁ+uQK

Hình 3.26ѫÿӗmҳFÿLӋn trӣShunt

ÿӇ ӣ ӝ iӟi h ÿ

C

IS

Shunt

IA

RS

I Rm

(19)

&yWKӇGQJFiFKFKX\ӇQÿәLWҫPÿRWKHRNLӇX6KXQW$\UWRQ(Hình 3.3):

0ҥFKÿRNLӇX6KXQW$\UWRQFyWҫPÿR KLNKyD.ӣYӏWUtWҫPÿRQKӓQKҩW ĈLӋQWUӣ6KXQWӣYӏWUt

RS1= R1+ R2+ R3 1ӝLWUӣFӫDFѫFҩXOj5m

.KLNKyD.ӣYӏWUt ĈLӋQWUӣ6KXQWӣYӏWUt

RS2= R1+ R2

1ӝLWUӣFӫDFѫFҩXOj5m+ R3 KLNKyD.ӣYӏWUt ĈLӋQWUӣ6KXQWӣYӏWUt

RS2 = R1

1ӝLWUӣFӫDFѫFҩXOj5m+ R3+ R2

9tGͭ&KRFѫFҩXÿRFyQӝLWUӣ5m= 1k:'zQJÿLӋQOӟQQKҩWTXDFѫFҩXOjPA Tính FiFÿLӋQWUӣ6KXQWӣWҫPÿRP$WҫPÿRP$WҫPÿRP$ *LҧL ӢWҫPÿRP$ ÈSGөQJF{QJWKӭF max max * A tai m A S I I R I R Ta có max max 1 * A tai m A S I I R I R R R

R :

, 52 10 * 950 * 10 * 50 ӢWҫPÿRP$ ÈSGөQJF{QJWKӭF max max * A tai m A S I I R I R Ta có: max max 2 * A tai m A S I I R R I R R R 199 10 * 9950 ) ( * 10 * 50 3 6 R k R

k: :

ӢWҫPÿRP$ ÈSGөQJF{QJWKӭF max max A tai m A S I I R I R

Hình 3.3: MҥFKÿRNLӇu Shunt Ayrton

C

I3

IA

I R1 R2 R3

(20)

%͡P{Q&XQJ&̭SĈL͏Q Trang 23 Ta có: max max A tai m A S I I R R R I R R 1999 10 99950 ) ( 10

50 3 2

6

6 k R R k R R

: :

Thay vào ta có:

3

2

1 52,6

199 R R k R

R : :

:

47,337

200 1000 , 10467 R : 526 , 2000 , 1052 1999 , 52 1000 1 R R

R2= 52,6 - (47,337 + 0,526) = 4,737: 9ұ\JLiWUӏFiFÿLrQWUӣ6KXQWӣFiFWҫPÿROj

RS1= R1+ R2+ R3= 0,526 + 4,737 + 47,337 = 52,6 :

RS2 = R1+ R2= 0,526 +4,737 = 5,263 :

RS3 = R1= 0,526: G0ӣUӝQJWҫPÿRFKRFѫFҩXÿLӋQWӯ

7KD\ ÿәL Vӕ YzQJ Gk\ TXҩQ FKR FXӝQ Gk\ Fӕ ÿӏQK YӟL OӵF ÿLӋQ Wӯ ) NK{QJ ÿәL F = n1.I1= n2I2= n3I3=

9tGө) $PSHYzQJFKRWҫPÿR I1= 1A; I2= 5A; I3= 10A .KLÿy n1= 300 vòQJFKRWҫPÿR$

n2 YzQJFKRWҫPÿR$

n3 YzQJFKRWҫPÿR$ H0ӣUӝQJWҫPÿRFKRFѫFҩXÿLӋQÿӝQJ 0ҳFVRQJVRQJFiFÿLӋQWUӣ6KXQWYӟLFXӝQGk\GLÿӝQJ&iFKWtQKÿLӋQWUӣ6KXQW JLӕQJQKѭYӟLFiFKWtQKӣFѫFҩXWӯÿLӋQ ĈRGzQJÿLӋQ[RD\FKLӅX$& D1JX\rQOêÿR &ѫFҩXÿLӋQWӯYjÿLӋQÿӝQJÿӅXKRҥWÿӝQJÿѭӧFYӟLGzQJÿLӋQ[RD\FKLӅXGRÿyFy WKӇGQJKDLFѫFҩXQj\WUӵFWLӃSYj PӣUӝQJWҫPÿRQKѭ$PSHPpWÿRGzQJÿLӋQ PӝW FKLӅX

5LrQJFѫFҩXWӯÿLӋQNKLGQJSKҧLELӃQÿәLGzQJÿLӋQ[RD\FKLӅXWKjQKGzQJÿLӋQ PӝWFKLӅX1JRjLUDGRWtQKFKtQK[iFFӫDFѫFҩXWӯÿLӋQQrQFѫFҩXQj\UҩWWK{QJGөQJ WURQJSKҫQOӟQ$PSHPpWWURQJPi\ÿRYҥQQăQJ920

(21)

-'QJÿLӋQWUӣ6KXQWYjÿL{WFKRFѫFҩXWӯÿLӋQ$PSHPpWFKӍQKOѭX

ĈL{WPҳFQӕLWLӃSYӟLFѫFҩXGRÿyGzQJÿLӋQLcLtbTXDFѫFҩXGzQJFzQOҥLTXDÿLӋQ WUӣ6KXQW

1yLFKXQJFiF$PSHPpWFKӍQKOѭXFyÿӝFKtQK[iFNK{QJFDRGRKӋVӕFKӍQKOѭX WKD\ÿәLWKHR QKLӋWÿӝWKD\ÿәLWKHRWҫQVӕ 9uYұ\FҫQSKҧLE QKLӋWÿӝYjEWҫQVӕ 'ѭӟLÿk\OjFiFVѫÿzEWҫQVӕFӫDFiF$PSHPpWFKӍQKOѭXEҵQJFXӝQFҧPYjWөÿLӋQ&

0һW NKiF FiF $PSHPpW Wӯ ÿLӋQ FKӍQK OѭX ÿѭӧF WtQK WRiQ YӟL GzQJ ÿLӋQ Fy GҥQJ KuQKVLQKӋVӕKình dáng Khd= 1,1

I Dk BSW

hd

D

.KLÿRYӟLFiFGzQJÿLӋQNK{QJSKҧLKuQKVLQVӁJk\VDLVӕ

ѬXÿLӇPFӫDGөQJFөQj\OjÿӝQKҥ\FDRWLrXWKөF{QJVXҩWQKӓFyWKӇOjPYLӋFӣ WҫQVӕ+]y1kHz

1KѭӧFÿLӇPÿӝFKtQK[iFWKҩS

- Ampemét ÿLӋQWӯOjGөQJFөÿRGzQJÿLӋQGӵDWUrQFѫFҩXFKӍWKӏÿLӋQWӯ0ӛLFѫ FҩXÿLӋQWӯÿѭӧFFKӃWҥRYӟLVӕ$PSHYjVӕYzQJQKҩWÿӏQK

9tGө

&XӝQGk\WUzQFy,: $YzQJFXӝQGҽWFy IW 100y150A YzQJGRÿyNKL PӣUӝQJWKDQJÿRFKӍFҫQWKD\ÿәLVDRFKR,:OjKҵQJVӕEҵQJFiFKFKLDÿRҥQGk\WKjQK QKLӅXÿRҥQEҵQJQKDXYjWKD\ÿәLFiFKQӕLJKpSFiFÿRҥQÿyQKѭKuQKDÿӇÿRGzQJ ÿLӋQQKӓKuQKEÿӇÿRGzQJÿLӋQWUXQJEuQKKuQKFÿӇÿRGzQJÿLӋQOӟQ

Hình 3.4: Ampemét chӍQKOѭX

C

RM

RS

ICLTB

VD IS

+

-IAC

+uQK&iFSKѭѫQJSKiSEWҫn sӕcӫa Ampemét chӍQKOѭX

a.Bù tҫn sӕcӫa Ampemét chӍQKOѭXEҵng cuӝn cҧm

C

RCU

L RMN

RC

b.Bù tҫn sӕcӫa Ampemét chӍnh

OѭXEҵng tө ÿLӋn Ccҧm

C

C RCU

(22)

%͡P{Q&XQJ&̭SĈL͏Q Trang 25 - $PSHPpWÿLӋQÿӝQJWKѭӡQJVӱGөQJÿRGzQJÿLӋQӣWҫQVӕ+]KRһFFDRKѫQ (400yYӟLÿӝFKtQK[iFFDRFҩSy 0,2)

7\WKHRGzQJÿLӋQFҫQÿRPjFXӝQGk\WƭQKYjFXӝQGk\ÿӝQJÿѭӧFPҳFQӕLWLӃS KRһFVRQJVRQJKuQK

- KLGzQJÿLӋQFҫQÿRQKӓKѫQ$QJѭӡLWDPҳFQӕLWLӃSFXӝQGk\WƭQK$1,A2) FXӝQGk\ÿӝQJKuQKD

- KLGzQJÿLӋQFҫQÿROӟQKѫQ$FXӝQGk\WƭQKYjFXӝQGk\ÿӝQJÿѭӧFJKpS song song (hình 3.7b)

$PSHPpWÿLӋQÿӝQJFyÿӝFKtQK[iFFDRQrQÿѭӧFVӱGөQJOjPGөQJFөPүX&iF SKҫQ Wӱ / WURQJ Vѫ ÿӗ GQJ ÿӇ E VDL Vӕ WҫQ Vӕ Yj WҥR FKR GzQJ ÿLӋQ ӣ FXӝQ Gk\ trùng pha

.KLFҫQÿRFiFGzQJÿLӋQOӟQÿӇPӣUӝQJWKDQJÿRQJѭӡLWDFzQGQJPi\ELӃQ GzQJÿLӋQ%,

&ҩX WҥRFӫDELӃQGzQJJӗPFyFXӝQGk\

b.ĈRGzQJÿLӋn trung bình

Hình 3.6: MӣrӝQJWKDQJÿRFӫD$PSHPpWÿLӋn tӯ

I1

I2

I I

FĈRGzQJÿLӋn lӟn

I I

DĈRGzQJÿLӋn nhӓ

+uQK6ѫÿӗ $PSHPpWÿLӋQÿӝng

b A-mét

B A1

L1

R1

A2

L2

R2

a mA-mét

B A2

(23)

- &XӝQVѫFҩS:1, ÿѭӧFPҳFQӕLWLӃSYӟLPҥFKÿLӋQFyGzQJ,1FҫQÿR

- &XӝQWKӭFҩS:2 PҳFQӕLWLӃSYӟL$PSHPpWFyGzQJÿLӋQ,2FKҥ\TXD ĈӇÿҧPEҧRDQWRjQFXӝQWKӭFҩSOX{QOX{QÿѭӧFQӕLÿҩW

&XӝQWKӭFҩSÿѭӧFFKӃWҥRYӟLGzQJÿLӋQÿӏQK PӭFOj$ &KҷQJ KҥQWDWKѭӡQJ JһS Pi\ ELӃQ GzQJ Fy GzQJ ÿLӋQ ÿӏQK PӭF Oj $ $ $ $ 7Uӯ QKӳQJWUѭӡQJKӧSÿһFELӋW

7DFyWӹVӕELӃQGzQJ

1 2

W W I I Ki

7ӹVӕ.iEDRJLӡFǊQJÿѭӧFWtQKVҹQNKLWKLӃWNӃ%,QrQNKLWUrQDPSHPpWFyVӕÿR

I2WDGӉGjQJWtQKQJD\ÿѭӧF,1

I1 = KiI2

9tGө%LӃQGzQJÿLӋQFyGzQJÿLӋQÿӏQKPӭFOj$:1= vòng

;iFÿӏQKVӕYzQJFӫDFXӝQWKӭFҩSYjWuP[HPNKLDPSHPpWWKӭFҩSFKӍ,2 = 2,85A WKuGzQJÿLӋQFXӝQVѫFҩSOjEDRQKLrX

*LҧL

- 7ӹVӕELӃQGzQJ 120

600

i

K

- 6ӕYzQJFXӝQWKӭFҩS:2 = KiW1= 120 vòng

- 'zQJÿLӋQVѫFҩS,1= KiI2=120 x 2,85 = 342A

Ampe kìm:

$PSHNuPOjPӝWPi\ELӃQGzQJFyOҳSVҹQPӝWDPSHPpWYjRFXӝQWKӭFҩSĈѭӡQJ Gk\FyGzQJÿLӋQFҫQÿRÿyQJYDLWUzFXӝQVѫFҩS0ҥFKWӯFӫD$PSHNuPFyWKӇPӣUD QKѭPӝWFKLӃFNuP.KLFҫQÿRGzQJÿLӋQFӫDPӝWÿѭӡQJGk\QjRÿyFKӍYLӋFPӣPҥFKWӯ UDYjFKRÿѭӡQJGk\ÿyYjRJLӳDNuPUӗLÿyQJPҥFKWӯOҥL$PSHPpWJҳQWUrQNuPVӁFKӍ FKRELӃWJLiWUӏGzQJÿLӋQFҫQÿR

&KӭFQăQJFKtQKFӫD$PSHNuPOjÿRGzQJÿLӋQ[RD\FKLӅXÿӃQYjLWUăPDPSHPj NK{QJFҫQSKҧLFҳWPҥFKÿLӋQWKѭӡQJGQJÿӇÿRGzQJÿLӋQWUrQÿѭӡQJGk\GzQJÿLӋQ TXDFiFPi\PyFÿDQJOjPYLӋF

I1

A W1

W2

I2

(24)

%͡P{Q&XQJ&̭SĈL͏Q Trang 27 NgoàiUDWUrQ$PSHNuPFzQFyFiFWKDQJÿR$&9'&9YjWKDQJÿRÿLӋQWUӣ ѬXÿLӇPJӑQQKҽVӱGөQJWKXұQWLӋQDQWRjQ7KѭӡQJGQJÿӇÿRGzQJÿLӋQWUrQ ÿѭӡQJGk\GzQJÿLӋQFKҥ\TXDFiFPi\PyFÿDQJYұQKjQKPjNK{QJFҫQFҳWPҥFK

1KѭӧFÿLӇPFKӏXҧQKKѭӣQJFӫDWӯWUѭӡQJQJRjL ĈRÿLӋQiS

'өQJFөÿRYjSKѭѫQJSKiSÿR

D'өQJFөÿRĈӇÿRÿLӋQiSÿӑFWKҷQJWUӏVӕWDGQJ9{QPpW êKLӋX

E3KѭѫQJSKiSÿR

KhiÿR9{QPpWÿѭӧFPҳFVRQJVRQJYӟLÿRҥQPҥFKFҫQÿR

Ta có:

V V

r U

I (1)

rV +ҵQJVӕELӃW,V VX\UDÿLӋQiS8

OFF

:

DCV ACV

ACA

2

4

6

7

8

:

V A

Hình 3.9: KӃt cҩu ngồi cӫa Ampe kìm

1.Gӑng kìm; Chӕt mӣgӑng kìm;

3 Núm xoay; Nút khóa kim;

V

+uQK6ѫÿӗmҳc vơn mét V

rV

I I

(25)

'zQJTXDFѫFҩX,V làmTXD\NLPPӝWJyFWӹOӋYӟLGzQJÿLӋQ,V FǊQJFKtQKWӹOӋ YӟLÿLӋQiSFҫQÿR87UrQWKDQJÿRWDJKLWKҷQJWUӏVӕÿLӋQiS

7ӯVX\UD,V Jk\VDLVӕPXӕQJLҧPVDLVӕWKuSKҧLWăQJÿLӋQWUӣUV 0һWNKiF9{QPpWFǊQJWLrXWKөPӝWOѭӧQJF{QVXҩW V V r U P

rV FjQJOӟQWKu

PVFjQJQKӓÿLӋQiS8ÿRÿѭӧFFjQJFKtQK[iF ĈRÿLӋQiS'&

D1JX\rQOêÿR

ĈLӋQiSÿѭӧFFKX\ӇQWKjQKGzQJÿLӋQÿRÿLTXDFѫFҩXÿR 1ӃXFѫFҩXÿRFy,maxYjÿLӋQWUӣQӕLWLӃS5WKu

MAX m do do I R R V I d

9ӟL5mOjÿLӋQWUӣWURQJFӫDFѫFҩXÿR

7әQJWUӣYjR9{QNӃ=V= R + Rm

&iFFѫFҩXWӯÿLӋQÿLӋQWӯÿLӋQÿӝQJÿӅXÿѭӧFGQJOjP9{QPpW'&%ҵQJFiFK QӕLWLӃSÿLӋQWUӣÿӇKҥQFKӃGzQJÿLӋQTXDFѫFҩXFKӍWKӏ5LrQJFѫFҩXÿLӋQÿӝQJFXӝQ Gk\GLÿӝQJYjFXӝQGk\FӕÿӏQKPҳFQӕLWLӃS

E0ӣUӝQJJLӟLKҥQÿR

0ӛLFѫFҩXÿRFKӍJLӟLKҥQÿRÿѭӧFPӝWJLiWUӏQKҩWÿӏQK9uYұ\ÿӇPӣUӝQJJLӟL KҥQ ÿR FӫD 9{QPpW KL ÿLӋQ iS FҫQ ÿR YѭӧW TXi JLӟL KҥQ ÿR FKR SKpS FӫD 9{QPpW QJѭӡLWDPҳFWKrPPӝWÿLӋQWUӣSKө5PQӕLWLӃSYӟLFѫFҩXÿR

Ta có: UP= IRP

P P

R U

I

UV= I.rV

V V r U I V V P P r U R U V P V P r R U U V V P V V P r r R U U U

Vì: UP+ UV= U

nên: V P V V P V r R r r R U U ĈһW U V P n r R U V n U U

U = UV.nu

V P U r R n ( EӝLVӕÿLӋQWUӣSKө +ӋVӕQu FKRELӃWNKLPҳFÿLӋQWUӣSKөWKuWKDQJÿRFӫD9{QPpWÿѭӧFPӣUӝQJQu OҫQ

1ӃX5pUҩWOӟQVRYӟLUVWKuWKDQJÿRFjQJÿѭӧFPӣUӝQJ

RP FjQJOӟQVRYӟLUvWKuFӣÿRFjQJÿѭӧFPӣUӝQJ

+uQKGQJÿLӋn trӣphө(RPÿӇmӣrӝng giӟi hҥQÿRFKR9{QPpW

V rV

I

Phөtҧi

RP

Up UV

(26)

%͡P{Q&XQJ&̭SĈL͏Q Trang 29 0XӕQFyQKLӅXWҫPÿRNKiFQKDXWDGQJPҥFKÿRQKѭVDX

Ĉk\FǊQJOjPҥFKÿRÿLӋQiS'&WKѭӡQJGQJWURQJÿRYҥQQăQJ

7әQJWUӣYjRFӫD9{QPpWWKD\ÿәLWKHRWҫPÿRQJKƭDOjWәQJWUӣYjRFjQJOӟQWKu WҫPÿRÿLӋQiSFjQJOӟQ&KRQrQQJѭӡLWDGQJ WUӏVӕÿӝQKҥ\:9'&FӫD9{QPpWÿӇ [iFÿӏQKWәQJWUӣYjRFKRPӛLWҫPÿR

9tGͭ9{QPpWFyÿӝQKҥ\N:/ VDC ӢWҫPÿR9WәQJWUӣYjROj

ZV1= 2,5V * 20 k:/ VDC = 50 k: ӢWҫPÿR9WәQJWUӣYjROj

ZV2=10V * 20 k:/ VDC = 200 k:

ĈRÿLӋQiS$&

ĈӕLYӟLFѫFҩXÿRÿLӋQÿӝQJÿLӋQWӯ9{QPpW$&GQJQKӳQJFѫFҩXQj\SKҧLPҳF QӕLWLӃSÿLӋQWUӣYӟLFѫFҩXÿRQKѭ9{QPpW'&9uKDLFѫFҩXQj\KRҥWÿӝQJYӟLWUӏKLӋX GөQJFӫDGzQJ[RD\FKLӅX5LrQJFѫFҩXWӯÿLӋQSKҧLGQJSKѭѫQJSKiSELӃQÿәLQKѭӣ $PSHPpWWӭFOjGQJÿL{WFKӍQKOѭX

D9{QPpWWӯÿLӋQFKӍQKOѭXÿRÿLӋQiS[RD\FKLӅX

/jGөQJFөÿѭӧFSKӕLKӧSPҥFKFKӍQKOѭXYӟLFѫFҩXÿRWӯÿLӋQQKѭKuQKYӁVDX C

Rm R2

R3

R1

+

VÿR +

-V1

V2

V3

Hình 3.12: MҥFKÿRÿLrQiS'&QKLӅu tҫPÿR

Hình 3.13: Vơnmét tӯ ÿLӋn chӍQKOѭXÿRÿLӋn áp xoay chiӅu

- R1ÿLӋn trӣbù nhiӋWÿӝlàm bҵQJGk\ÿӗng

- R2ÿLӋn trӣmanganin

C

R1

R2 C

U

C

Rp L

(27)

0ӣUӝQJWKDQJÿRӣ9{QPpWWӯÿLӋQFKӍQKOѭXFǊQJWѭѫQJWӵ9{QPpWWӯÿLӋQPӝW FKLӅX

E9{QPpWÿLӋQWӯ

/j GөQJ Fө ÿR ÿLӋQ iS [RD\ FKLӅX WҫQ Vӕ F{QJ QJKLӋS &XӝQ Gk\ SKҫQ WӍQK Fy Vӕ YzQJOӟQWӯyYzQJĈӇPӣUӝQJWKDQJÿRQJѭӡLWD PҳFQӕLWLӃSYӟLFXӝQGk\ FiFÿLӋQWUӣSKөQKѭKuQKGѭӟLÿk\7өÿLӋQ&GQJÿӇEWҫQVӕNKLÿRӣWҫQVӕFDRKѫQ WҫQVӕF{QJQJKLӋS

F9{QPpWÿLӋQÿӝQJ

&ҩXWҥRFӫD9{QPpWÿLӋQÿӝQJJLӕQJ$PSHPpWÿLӋQÿӝQJQKѭQJVӕYzQJFXӝQGk\ WӍQKOӟQKѫQWLӃWGLӋQGk\QKӓKѫQ

7URQJ9{QPpWÿLӋQÿӝQJFXӝQGk\WӍQKYjFXӝQGk\ÿӝQJÿѭӧFPҳFQӕLWLӃSQKDX &XӝQGk\WӍQKÿѭӧFFKLDWKjQKSKҫQ$1và A2KuQKYӁWUrQ+uQK

.KLÿRÿLӋQiSQKӓKѫQKRһFEҵQJ9KDLÿRҥQ$1 A2ÿѭӧFPҳFsong song YӟLQKDX1ӃXÿLӋQiS8!9FiFÿRҥQ$1 A2 ÿѭӧFPҳFQӕLWLӃSQKDX

1JRjLUDÿӇPӣUӝQJSKҥPYLÿROӟQKѫQ7UrQ9QJѭӡLWDGQJPi\ELӃQ ÿLӋQiSÿROѭӡQJ%8

7ѭѫQJWӵQKѭ%,%8GQJÿROѭӡQJWURQJPҥFKÿLӋQ[RD\FKLӅXÿLӋQiSFDR&ҩX WҥRWѭѫQJWӵQKѭPi\ELӃQiSWK{QJWKѭӡQJWDFyWӹVӕELӃQiS

2

W W U U KU

U1= KU.U2

ĈLrQiSÿӏQKPӭFWKӭFҩS82 OX{QOX{QÿѭӧFWtQKWRiQOj9WUӯPӝWVӕWUѭӡQJ KӧSÿһFELӋW

C

Rm Rp1 Rp2 Rp3

C

U1 U2 U3

+uQK9{QPpWÿLӋn tӯ

Hình 3.15: Máy biӃQÿLӋn áp

W2

V U2 U1

(28)

%͡P{Q&XQJ&̭SĈL͏Q Trang 31 &KҷQJKҥQ

ĈӕLYӟLÿLӋQiSN9QJѭӡL WDWKѭӡQJGQJ%8 FyÿLӋQiSÿӏQK PӭFOj 10000/100V

ĈӕLYӟLÿLӋQiSN9QJѭӡL WDWKѭӡQJGQJ%8 FyÿLӋQiSÿӏQK PӭFOj 35000/100V

9tGө7KDQKJySÿLӋQiSN9FyÿһWELӃQÿLӋQiS9ErQWKӭFҩS PҳF9{QPpWYjFiFGөQJFөÿR.KL9{QPpWFKӍ8 9WKuÿLӋQiSWUrQWKDQKJySOj bao nhiêu?

*LҧL

7DFy7ӹVӕELӃQiS

2 U U

KU 1150

100 115000

ĈLӋQiSWUrQWKDQKJySFKtQKOjÿLӋQiSVѫFҩSFӫD%8WDFy U1 = KU.U2= 1150*95 = 109250V = 109,25kV

9ұ\ÿLӋQiSWUrQWKDQKJySOjN9

3.3. ĈRF{QJVXҩW

ĈRF{QJVXҩWWiFGөQJPҥFKPӝWFKLӅX DĈRF{QJVXҩWPҥFKPӝWFKLӅX

-ĈRJLiQWLӃS

7DELӃWF{QJVXҩWPҥFKPӝWFKLӅXÿѭӧFWtQKWKHRF{QJWKӭF3 8, 1rQWDÿRF{QJVXҩWEҵQJFiFKPҳFVѫÿӗÿRQKѭVDX

+ Dùng Am-pe-PpW[iFÿӏQKWUӏVӕGzQJÿLӋQTXDWҧL + Dùng Vôn-PpW[iFÿӏQKWUӏVӕÿLӋQiSJLiQJWUrQWҧL

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Hình 3.16: MҥFKÿRF{QJVXҩt dùng V-mét A-mét

UDC

+

-+ +

-R V

(29)

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(30)

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Hình 3.19: Hai cách nӕi Oátmét

(31)

http://www.ebook.edu.vn FĈRF{QJVXҩWPҥFKSKD

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Hình 3.22: 6ѫÿӗdùng Oátmét ba pha ba phҫn tӱ

(32)

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(33)

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a.Mҥch pha dây

A B C Z Z Z * * P

b.Mҥch pha dây +uQKVѫÿӗdùng mӝtOátmétÿRF{QJVXҩt mҥFKSKDÿӕi xӭng

M

s Q

(34)

%͡P{Q&XQJ&̭SĈL͏Q Trang 37

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W W

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ĈRÿLӋQQăQJ

3.5.1 &{QJGөQJ

ĈӇÿRÿLӋQQăQJWURQJPҥFKÿLӋQ[RD\FKLӅXQJѭӡLWDGQJF{QJWѫÿLӋQFzQJӑLOj Pi\ÿӃPÿLӋQQăQJÿLӋQNӃKD\ÿLӋQQăQJNӃ1yLFiFKNKiFF{QJWѫ ÿLӋQ OjORҥLPi\ ÿRGQJÿӇÿROѭӧQJÿLӋQQăQJWLrXWKөFӫDSKөWҧL6ӕFKӍWUrQF{QJWѫÿѭӧFWtQKEҵQJ KWh

3.5.2 &ҩXWҥRYjQJX\rQOêOjPYLӋFFӫDF{QJWѫÿLӋQ D&ҩXWҥRKuQK

I I2

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(35)

- 3KҫQWƭQK

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Trөc quay (2) HӋthӕng bánh

[HUăQJ

Bánh xe trөc sӕ(4)

(36)

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Mq = K1 P

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n 3

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(

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1DP FKkP YƭQK FӱX QDP châm hãm)

ĈƭDQK{P

6

8

1,

(37)

3.5.3 &iFKPҳFF{QJWѫYjRPҥFKFҫQÿR:

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Nguӗn Tҧi

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Tҧi A

B C N

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1ӃXJLӳ8Yj5P NK{QJÿәLWKuGzQJÿLӋQ,VӁSKөWKXӝFYjRJLiWUӏFӫDÿLӋQWUӣ5X,

WӯÿyJyFOӋFKFӫDNLPOjD VӁSKөWKXӝFYjRJLiWUӏFӫDÿLӋQWUӣFҫQÿR7UrQWKDQJÿR QJѭӡLWDJKLWUӵFWLӃSWUӏVӕFӫDÿLӋQWUӣ

ĈLӋQWUӣ5PÿѭӧFFKӑQVDRFKRNKLҩQ15X 7ӭFOj,m PD[GzQJFӵFÿҥL

TXDFѫFҩXWKuNLPFӫD{PPpWTXD\KӃWPһWFKLDÿӝYjNKLKӣPҥFKWKu5X=f7ӭFOj

Im NK{QJFyGzQJTXDFѫFҩXWKuNLPÿӭQJ \rQ1KѭYұ\ ӣ{PPpW PһWFKLD ÿӝ

QJѭӧFYӟLFKLӅXTXD\FӫDNLP

7URQJTXiWUuQKGQJ{PPpWÿRÿLӋQWUӣÿLӋQiSFӫDSLQ8QJXӗQVӁJLҧPGҫQOjP

NӃWTXҧÿRNpPFKtQK[iF9uYұ\WUѭӟFPӛLOҫQÿRSKҧLҩQQ~W1[XӕQJÿӇFKӍQKNLP ÿ~QJYӏWUtNK{QJVDXÿyPӟLEҳWÿҫXÿR

- ĈҩXsong song:

ĈLӋQ WUӣFҫQÿRÿѭӧFÿҩXVRQJVRQJYӟLFѫFҩXÿR+uQK

/jORҥLGөQJFөÿRWURQJÿy5xÿѭӧFPҳFVRQJVRQJYӟLFѫFҩXÿRQKѭKuQKYӁWUrQ

C

Unguӗn Rp

N

Rm

+uQKĈRÿLӋn trӣtrӵc tiӃp

&&ѫFҩXÿRNLӇu tӯ ÿLӋn

RmĈLӋn trӣtrong cӫDFѫFҩX.K{QJÿәi)

UnguӗnĈLӋn áp nguӗn mӝt chiӅu (Pin)

Unguӗn

RX Rp

C Rm

Im IX I RM

(51)

ѬXÿLӇPFӫD{PPpWORҥLQj\OjFyWKӇÿRÿѭӧFÿLӋQWUӣWѭѫQJÿӕLQKӓYjÿLӋQWUӣ WURQJFӫD{m mét R:QKӓNKLGzQJÿLӋQWӯQJXӗQFXQJFҩSNK{QJOӟQOҳP'Rÿy5xPҳF

VRQJVRQJYӟLFѫFҩXÿRQrQNKL5x=f FKѭDFy5xGzQJÿLӋQTXDFѫFҩXÿROjOӟQQKҩW

YӟL5x GzQJÿLӋQTXDFѫFҩXÿROjJҫQEҵQJNK{QJ7KDQJÿRÿѭӧFNKҳFÿӝJLӕQJQKѭ

Vôn mét

ĈLӅX FKӍQK WKDQJ ÿR FӫD {PPpW WURQJ WUѭӡQJ KӧS QJXӗQ FXQJ FҩS WKD\ ÿәL FǊQJ GQJPӝWELӃQWUӣ5M YjÿLӅXFKӍQKӭQJYӟL5x = f;iFÿӏQK5M FǊQJJLӕQJQKѭVѫÿӗ

{PPpWPҳFQӕLWLӃS

EĈREҵQJ0rJ{PpW

0rJ{PpWOjGөQJFөÿRÿLӋQWUӣOӟQPj{PPpWNK{QJÿRÿѭӧF

Mêgômét WKѭӡQJGQJÿRÿLӋQWUӣFiFKÿLӋQFӫDPi\ÿLӋQNKtFөÿLӋQFXӝQGk\ Pi\ÿLӋQ

.êKLӋX

-&ҩXWҥR+uQK

M::

RX RP

I1

I2 N S

M2 M1

+

-1 2

M::

(52)

*ӗPWӹVӕNӃWӯ ÿLӋQ YjPDQKrW{NLӇXWD\TXD\GQJOjPQJXӗQÿӇÿR

3KҫQÿӝQJJӗPFyNKXQJGk\YjÿһWOӋFKQKDX0TXҩQQJѭӧFFKLӅXQKDX NK{QJFyOz[RÿӕLNKiQJ.KHKӣJLӳDQDPFKkPYjO}LWKpSNK{QJÿӅXQKҵPWҥRQrQ PӝWWӯWUѭӡQJNK{QJÿӅX

1JXӗQÿLӋQFXQJFҩSFKRFXӝQGk\OjPӝWPi\SKiWÿLӋQPӝWFKLӅXTXD\WD\Fy ÿLӋQiSWӯy1000)V

ĈLӋQWUӣFҫQÿR5XÿѭӧF PҳFQӕLWLӃSYӟLFXӝQGk\

ĈLӋQWUӣSKө5PÿѭӧF PҳFQӕLWLӃSYӟLFXӝQGk\

- Nguyên lý:

.KLÿRWDTXD\Pi\SKiWÿLӋQYӟLWӕFÿӝÿӅXNKRҧQJyYzQJSK~W6ӭFÿLӋQ ÿӝQJFӫDPi\SKiWÿLӋQVӁWҥRUDKDLGzQJÿLӋQ,1 I2 WURQJFXӝQGk\QJKƭDOj[XҩW

KLӋQP{PHQTXD\01và M2QJѭӧFFKLӅXQKDX1KѭYұ\NLPVӁTXD\WKHRKLӋXVӕFӫD

P{PHQYjFKӍGӯQJOҥLNKL01 =M2

9uP{PHQTXD\WӹOӋYӟLGzQJÿLӋQQrQWDFy

M1= K1.I1 M2= K2.I2

'RÿyNKLNLPFkQEҵQJWKu

K1.I1= K2.I2 KRһF

1 2 K K I I 'RWӯWUѭӡQJSKkQEӕNK{QJÿӅXWURQJNKHKӣNK{QJNKtQrQWӹVӕ K K SKөWKXӝF

YjRYӏWUtFiFFXӝQGk\QJKƭDOjSKөWKXӝFYjRJyFTXD\DFӫDNLP

x f K K I I 2

0һWNKiFFiFGzQJÿLӋQ,1 I2EҵQJ

X R r U I 1 P R r U I 2

Nên: ( )

1 2

1 f x

R r R r I I X P

1JKƭDOjJyFTXD\DFӫDNLPSKөWKXӝFYjR5X(vì r1, r2và RpÿӅXNK{QJÿәL

7UrQWKDQJÿRFӫD0rJ{PpWQJѭӡLWDJKLWUӵFWLӃSWUӏVӕÿLӋQWUӣN:, M:WѭѫQJӭQJ YӟLFiFJyFTXD\FӫDNLP

(53)

- 9uNK{QJFyOz[RFkQE̹QJQrQNKLNK{QJÿRNLPVͧͅP͡WY͓WUtḘWNǤWUrQ

P̿WV͙

- .K{QJQrQFK̩PYjRÿ̯XUDFͯDGk\ÿ͋WUiQKE͓ÿL͏QJL̵WNKLTXD\

FĈRÿLӋQWUӣÿҩWEҵQJFҫXÿR0&-07:

'ӵDWUrQQJX\rQWҳFFӫDWӹVyNӃWӯÿLӋQÿӇFKӃWҥRFҫXÿR0&-Ĉk\OjGөQJ FөÿRÿLӋQWUӣWLӃSÿҩW5WÿÿӑFWKҷQJYjFyWrQJӑLOj7êrơmét

-&ҩXWҥR

&ҩX WҥRFӫD0&-07 (Hình 4.7)

*ӗP

Khung dây K1và K2

0i\SKiWÿLӋQPӝWFKLӅX

%LӃQWUӣSKө5P OӟQKѫQU1,r2 (r1, r2 OjÿLӋQWUӣFӫDFiFFXӝQGk\.1, K2)

RWÿUҩWQKLӅX

&ӵF;QӕLFӑFFҫQÿR5Wÿ

&ӵF8OjFӵFiSQӕLYӟLFӑFSKөFiFKFӑFFҫQÿR5WÿPӝWNKRҧQJP

&ӑF,OjFӵFGzQJQӕLYӟLFӑFSKөFiFKFӑF8PӝWNKRҧQJP

- Nguyên lý:

1ӕLFiFFӵF;8,FӫDFҫXÿRWKHRVѫÿӗWUrQ 4XD\Pi\SKiWÿӇFXQJFҩS,1cho K1

I1WӟL;FKLDWKjQKWKjQKSKҫQ

, I I2

20 m 20 m

X U I

I2

,¶1 I1

I1

RP

F r1, K1

r2, K2

(54)

1

I [XӕQJÿLӋQWUӣWLӃSÿҩW5Wÿ.) I2ÿӃQFXӝQGk\.2

Do RpOӟQKѫQ5Wÿvà rUnên I2 QKӓKѫQUҩWQKLӅXI1' ' I | I ru+ Rp+ r2 | Rp

7UrQVѫÿӗ5Wÿ (ru+ Rp+ r2) nên: I1'.RWÿ= I2.(ru+ Rp+ r2) '

1 I

RWÿ= I2.RP

td P

R R I I

1 '

2 ' I I K

D

hay

td P

R R K

D

Khi RP KҵQJVӕWKuDFKӍFzQSKөWKXӝF RWÿ9ұ\ELӃWD WD[iFÿӏQKÿѭӧF5Wÿ FҫQ

ÿR

7KHRVѫÿӗWUrQFӫD0&-QKұQWKҩ\GzQJÿLӋQTXDÿҩWOjGzQJPӝWFKLӅXVӁJk\ UDKLӋQWѭӧQJÿLӋQSKkQGXQJGӏFKÿLӋQSKkQWURQJÿҩWOjPFKR5WÿEӏELӃQÿәLGүQÿӃQ

NӃWTXҧÿR5WÿFyVDLVӕOӟQĈӇNKҳFSKөFÿLӅXQj\QJѭӡLWDGQJWKrPYjQKJySÿLӋQ cho MC-ÿӇELӃQGzQJÿLӋQTXDFiFFӑFWLӃSÿҩWOjGzQJ[RD\FKLӅXFzQGzQJTXD0&

-YүQOjGzQJPӝWFKLӅX 7DFyVѫÿӗQKѭVDX

20m 20m

I

F

X

r1,K1

r2,K2

U RP

9jQKJySÿLӋn

(55)

4.2. ĈRÿLӋQFҧPL:

.KiLQLӋP

&XӝQFҧPOêWѭӣQJOjFXӝQ Gk\FKӍFyWKjQKSKҫQÿLӋQNKiQJ;L=Z/KRһFFKӍOj

WKXҫQ NKLӃW Oj ÿLӋQ FҧP / QKѭQJ WURQJ WKӵF WӃ FiF FXӝQ Gk\ QJRjL WKjQK SKҫQ ÿLӋQ

kháng XLFzQFyÿLӋQWUӣFӫDFXӝQGk\5LĈLӋQWUӣ5LFjQJOӟQÿӝSKҭPFKҩWFӫDFXӝQ

Gk\FjQJNpP1ӃXJӑL4OjÿӝSKҭPFKҩWFXӝQGk\WKu4ÿѭӧFÿһFWUѭQJEӣLWӹVӕJLӳD ÿLӋQNKiQJ;L YjÿLӋQWUӣFӫDFXӝQGk\ÿy

L L

R X Q

6ѫÿӗ9{QPpW$PSHPpW 0ҥFKÿRÿѭӧFPҳFQKѭKuQK

7әQJWUӣFӫDFXӝQGk\ÿѭӧF[iFÿӏQK

2

) ( XY

X L

R I U

Z

L2XZ

= Z2.R2x

L2x 12 (Z2 R2X)

Y

2

X

x Z R

L

Y

ĈLӋQWUӣ5XÿѭӧF[iFÿӏQKWUѭӟF

+ӋVӕSKҭPFKҩW

L L

R X

Q WKD\VӕYjRQ

6ѫÿӗ9{QPpW$PSHPpWYj2iWPpW+uQK

V

A

LX

RX

U

A

+uQKĈRÿLӋn cҧm bҵng Vônmét Ampemét

*

V

A W

LX

RX

U V

A * W

(56)

7UѭӡQJKӧSPҥFKÿRGQJ WKrP2iWPpWÿLӋQWUӣ5XFӫDFXӝQGk\ÿѭӧF[iFÿӏQK

EӣLELӇXWKӭFVDX I P Rx 7әQJWUӣFӫDFXӝQGk\ 2 ) ( XY

X L

R I U

Z Z2= R2X+ (LXZ)2 L2xY2= Z2.R2X

2 2 Y X x R Z L 4 2 I P I U Y 4X\ÿӗQJPүXVӕWDFy 2 I P I U Lx Y 2 2 P I U I Y 3&{QJVXҩWWLrXKDRFӫDFXӝQGk\ÿѭӧF[iFÿӏQKEҵQJ2iWPpW 8ĈӑFÿѭӧFWUrQ9{QPpW ,ĈӑFÿѭӧFWUrQ$PSHPpW +ӋVӕSKҭPFKҩW L L R X

Q WKD\VӕYjR Q

ĈRÿLӋQFҧPEҵQJFҫXÿRÿѫQJLҧQ 0ҥFKÿRÿѭӧFPҳFQKѭKuQK A R2 G LX R1 L1 D K B C

I2 I1

U~

Hình 4.11: CҫXÿR/xÿѫQJLҧn

L1: Cuӝn dây mүXWKD\ÿәLÿѭӧc trӏsӕ)

(57)

ĈLӅXFKӍQK51, R2 L1ÿӇFҫXFkQEҵQJ

.KLFҫXFkQEҵQJWDFy

L1R1= LXR2 1

2 L R R Lx

4.3. ĈRÿLӋQGXQJC:

4.3.1 KháiQLӋPYӅÿLӋQGXQJYjJyFWәQKDR

7өÿLӋQOêWѭӣQJOjWөÿLӋQNK{QJWLrXWKөF{QJVXҩWGzQJÿLӋQPӝWFKLӅXNK{QJÿL TXDWөQKѭQJWURQJWKѭFWӃGRFyOӟSÿLӋQP{LQrQYүQFyGzQJÿLӋQQKӓÿLTXDWӯFӵF Qj\ÿӃQFӵFNLD9uYұ\WURQJWөFyVӵWәQKDRF{QJVXҩW

6ӵ WәQ KDR F{QJ VXҩW Qj\ UҩW QKӓ Yj ÿӇ ÿiQK JLi Vӵ WәQ KDR FӫD Wө ÿLӋQ QJѭӡL WD WKѭӡQJÿRJyFWәQKDRWJG)

7өÿLӋQÿѭӧFELӇXGLӉQGѭӟLGҥQJPӝWWөOêWѭӣQJQӕLWLӃSYӟLPӝWÿLӋQWUӣ7өÿLӋQ WәQKDRtWKRһFQӕLVRQJVRQJYӟLPӝWÿLӋQWUӣ7өÿLӋQ WәQKDRQKLӅX

9ӟL7өÿLӋQFyWәQKDRQKӓGӵDYjRJLҧQÿӗYpFWѫWD[iFÿӏQKJyFWәQKDRQKѭVDX

UR= IR ;

C UC

Z

C I IR U

U tg

C R

Z

G tgG = R.Z.C (4.3.1a)

GOjJyFWәQKDRFӫD7өÿLӋQ 9ӟL7өÿLӋQWәQKDRQKLӅXWDFy

R U

IR ; IC= UZC U

UC UR

C R

I

UC

UR U I

G M

U

C R IC

I IR

I

IR

U

IC

M G

a Tө ÿLӋn có tәn hao nhӓ b Tө ÿLӋn có tәn hao lӟn

(58)

http://www.ebook.edu.vn C

U R I

I tg

C R

Z

G

C R tg

1

Z

G (4.3.1b)

6ѫÿӗ9{QPpW$PSHPpW 0ҥFKÿRÿѭӧFPҳFQKѭVDX

1ӃXVӵWәQKDRF{QJVXҩWFӫDÿLӋQP{LWөÿLӋQNK{QJÿiQJNӇWKuWәQJWUӣFӫDWө ÿLӋQ&X ÿѭӧF[iFÿӏQKEӣL9{QPpWYj$PSHPpWQKѭVDX

Z X

C I U

Z

U I

Cx (4.3.2)

1JXӗQWtQKLӋXFXQJFҩSFKRPҥFKÿROjQJXӗQWtQKLӋXKuQKVLQFyELrQÿӝYjWҫQ VӕNK{QJÿәL

6ѫÿӗ9{QPpW$PSHPpt Oátmét :

0ҥFKÿRÿѭӧFPҳFQKѭVDX

7UѭӡQJ KӧS PҥFKÿR GQJWKrP :DWPHWÿLӋQWUӣUz 5X FӫDWөÿLӋn CX ÿѭӧF[iF

ÿӏQKEӣLELӇXWKӭFVDX

2 I

P

Rx (4.3.3)

U V

A

CX

+uQK6ѫÿӗVônmét, Ampemét

U V

A

CX

W *

*

RX

(59)

http://www.ebook.edu.vn 7әQJWUӣFӫDWөÿLӋQ 2 ) ( Z X x C R I U

Z 2 2

) ( Z X x C R Z x x R Z C 2 2 Z 2 x x R Z C Z 2 2 ) ( I P I U Z 4 2 I P I U Z ) ( 1 2 U I P I

Z 2 2

1 P I U I

Z 2

2 P I U I Z

Thay Rx, Cxvà ZYjRF{QJWKӭF(4.3.1b)

C R tg Z

G (GJyFWәQKDRFӫDWөÿLӋQ

6ӵKDRPҩWF{QJVXҩWGRÿLӋQP{LFӫDWөFKREӣLF{QJWKӭF P = U.I.cosM

3KѭѫQJSKiSGQJ2iWPpWNK{QJFKtQK[iFNKL[iFÿӏQKÿLӋQGXQJFӫDQKӳQJWө ÿLӋQ Fy JyF WәQ KDRG QKӓ ĈӇ ÿR QKӳQJ Wө ÿLӋQ Fy JyF WәQ KDRG QKӓ QJѭӡL WD GQJ SKѭѫQJSKiSFҫXÿR ĈRÿLӋQGXQJFӫDWөEҵQJFҫXÿRÿѫQJLҧQ 0ҥFKÿRÿѭӧFPҳFQKѭKuQK A R2 G CX R1 C1 D K B C I2

I2 I1

I1

U

+uQK&ҫXÿRÿѫQJLҧQ

C1: Tө ÿLӋn mүXWKD\ÿәLÿѭӧc trӏsӕ)

CX: Tө ÿLӋn cҫQÿR

(60)

1JX\rQOêĈLӅXFKӍQK51, R2và C1ÿӇFҫXFkQEҵQJ

.KLFҫXFkQEҵQJWDFy

C1R1= CXR2 1

2 C R R Cx

7+Ӵ&+¬1+Ĉ2&È&7+Ð1*6Ӕ&Ӫ$0Ҥ&+Ĉ,ӊ15/9¬& ĈRÿLӋQWUӣ7UuQKWӵWKӵFKLӋQQKѭVDX

%ѭӟF: KҧRViWPi\ÿR.

4XDQViWNӃWFҩXQJRjLFӫDPi\ÿR[iFÿӏQKFiFWKDQJÿRYҥFKÿӑF 9ӁOҥLNӃWFҩXQJRjLYӟLÿҫ\ÿӫFK~WKtFK

7KX\ӃWPLQKWKXJӑQFiFKÿӑFVӕÿRӭQJYӟLWӯQJWKDQJÿRYҥFKÿӑFFөWKӇ

%ѭӟF7LӃQKjQKÿR

/ҳSFiFÿLӋQWUӣOrQEҧQJWKӵFWұSQKѭKuQK &KXҭQEӏPi\ÿRÿӇÿRÿLӋQWUӣ

ĈRYjÿӑFJLiWUӏFӫDWӯQJÿLӋQWUӣ ĈRWҥLFiFÿLӇPD-b; c-d ; e-f ;

*KLNӃWTXҧYjREҧQJ ĈRÿLӋQWUӣPҳFVRQJVRQJ

1ӕLWҳWE-d, a-FÿӇWҥRÿLӋQWUӣPҳFVRQJVRQJQKѭKuQK ĈRWҥLFiFÿLӇPÿmQӕLWҳW

*KLNӃWTXҧYjREҧQJ ĈRÿLӋQWUӣPҳFQӕLWLӃS

+ӣPҥFKWҥLD-c; e-JÿӇWҥRÿLӋQWUӣPҳFQӕLWLӃSQKѭKuQK ĈRWҥLFiFÿLӇPYӯDKӣPҥFK

+ GKLNӃWTXҧYjREҧQJ

ĈRQKLӅXÿLӋQWUӣPҳFQӕLWLӃSPҳFVRQJVRQJ

7KӵFKLӋQWѭѫQJWӵQKѭEѭӟFYjEѭӟFQKѭQJVӕÿLӋQWUӣQӕLWLӃSKRһFVRQJ

song 3,

.ӃWTXҧJKLYjREҧQJ

1KұQ[pWNӃWTXҧWKtQJKLӋP

ĈӕLFKLӃXNӃWTXҧWKӵFQJKLӋPYjOêWKX\ӃWFKRQKұQ[pWYӅVDLVӕFӫDSKpSÿR &KRELӃWFiFSKѭѫQJSKiSOjPKҥQFKӃVDLVӕ

(61)

%ҧQJ

R1 R2 R3 R4 R5 R6 R7 R8 R8 R10 R11 R12

%ҧQJ

R1// R2 R3//R4 R5//R6 R7//R8 R9//R10 R11//R12

%ҧQJ

R1+R2 R3+R4 R5+R6 R7=R8 R9+R10 R11+R12

%ҧQJ

R1+R2+R3 R1+

R1//R2//R3 R1//

&ặ8+,9ơ%ơ,73

$&kXKLWUFQJKLPNKiFKTXDQ

&kXKL\rXFXWUOLQKDQK

FNFiFFkXKLFKQYjW{HQFkXờ~QJQKWYjR{FWWQJQJ0L

cõuFKFyPWờ~QJ

(62)

a 0ҥFKÿDQJPDQJÿLӋQ

b. 0̩FKÿmÿ˱ͫFF̷WQJX͛Q

c 0ҥFKÿDQJOjPYLӋF

d 0ҥFKÿmÿѭӧFFҳWSKD

4.2 KhiÿRÿLӋQWUӣJyFTXD\FӫDNLPFjQJOӟQWKuNӃWOXұQ

a ĈLӋQWUӣUҩWOӟQ

b ĈLӋQWUӣFjQJOӟQ

c. ĈL͏QWUͧFjQJQK͗

d. 7XǤORҥLPi\ÿR

#ð #ð ӫ #ð

4.3 .KLÿRÿLӋQWUӣEҵQJPi\ÿRFKӍWKӏNLPWUӏVӕSKҧLÿѭӧF ÿӑFWӯ

a 3KҧLTXDWUiL

b 7UiLTXDSKҧL

c *LӳDUDELrQ

d 7̩LY͓WUtNLPGͳQJO̩L

#ð #ð #ð ӫ

4.4 0XӕQ NLӇP WUD FKҥP PiW FKҥP Yӓ FiF WKLӃW Eӏ ÿLӋQ GQJÿӗQJKӗÿRÿLӋQWUӣÿһWӣWKDQJÿR

a ;KRһF;

b. ;KR̿F;

c ;KRһF;

d ;.KRһF

(63)

4.5 .KL ÿLӋQ WUӣ FҫQ ÿR Fy JLi WUӏ OӟQ ÿӗQJ Kӗ 920 ÿӇ ӣ WKDQJÿRTXiQKӓWKuNLP VӁFKӍ:

D4XD\QKLӅXYѭӧWNKӓLWKDQJÿR E.LPGDRÿӝQJTXDQKYӏWUt:;

F.LPTXD\ṶWtWJ̯QQK˱FK͑ͧY{FQJ

GĈӑFEuQKWKѭӡQJUҩWFKtQK[iF

#ð #ð ӫ #ð

4.6 ĈӗQJKӗYҥQQăQJGQJÿӇÿR:

D ĈLӋQ WUӣ ĈLӋQ iS PӝW FKLӅX [RD\ FKLӅX 'zQJ ÿLӋQ PӝWFKLӅX[RD\FKLӅX

EĈLӋQWUӣĈLӋQiS[RD\FKLӅXYjGzQJÿLӋQPӝWFKLӅX FĈLӋQWUӣ ĈLӋQiS PӝWFKLӅX[RD\FKLӅXYjGzQJÿLӋQ [RD\FKLӅX

GĈL͏QWUͧĈL͏QiSP͡WFKL͉X[RD\FKL͉XYjGzQJÿL͏Q P͡WFKL͉X

#ð #ð #ð ӫ

4.7 1JXӗQ SLQ ErQ WURQJ Pi\ ÿR YҥQ QăQJ 920 Vӱ GөQJ PҥFKÿR

a.ĈLӋQiS[RD\FKLӅX

b.'zQJÿLӋQ'&

c.ĈL͏QWUͧ

d.7ҩWFҧFiFFKӭFQăQJ

#ð #ð ӫ #ð

4.8 7URQJPi\ÿRYҥQQăQJ920FyVӱGөQJELӃQWUӣ ÿLӅX FKӍQK::OjQKҵPPөFÿtFK

D+LӋXFKӍQKOҥLSKҫQFѫNKtFӫDFѫFҩXÿR

b.+L͏XFK͑QKQJX͛Q FXQJF̭SFKRP͟LP̩FKÿR

(64)

F7ăQJÿLӋQWUӣQӝLFӫDPi\ÿR G*LҧPVDLVӕFiQKkQ

4.9 'QJPi\ÿR920ÿӇÿRÿLӋQÿLӋQWUӣÿһWӣWKDQJÿR WKҩSÿLӅXFKӍQKNLPFKӍ::NKLFKX\ӇQVDQJWKDQJÿROӟQ KѫQNLPNK{QJFzQӣYӏWUtFǊOjGR

a NJXӗQSLQEӏ\ӃXQKLӅX E%LӃQWUӣÿLӅXFKӍQKEӏKӓQJ

c.1͡LWUͧFͯDP͟LWKDQJÿRNKiFQKDX

GĈLӋQWUӣTXHÿRFyJLiWUӏkP

#ð #ð ӫ #ð

4.10 .KLFKӑQ0rJ{PPHWÿӇÿRÿLӋQWUӣFiFKÿLӋQFăQFӭYjR: a.7ӕFÿӝTXD\FӫDPDQKrW{

b.ĈL͏QiSÿ͓QKPͱFFͯDWKL͇WE͓

c.&KҩWOѭӧQJFӫDYӓWKLӃWEӏ

d.*LӟLKҥQÿRFӫDPi\

#ð ӫ #ð #ð

4.11 6ӕFKӍFӫD0rJ{PPpWFKӍFKtQK[iFNKL

a.4XD\PDQKHWRWKұWÿӅXWD\

b.4XD\PDQKHWRÿӃQÿӫÿLӋQiS

c LP͝Qÿ͓QKNK{QJFzQGDRÿ͡QJ

d.ĈqQEiRViQJOrQ

#ð #ð ӫ #ð

4.12 .KLFKѭDTXD\PDQKHWRNLPFӫD0rJ{PHWQҵPӣYӏWUt

a./ӋFKYӅErQSKҧL

(65)

b.1ҵPKҷQYӅErQSKҧLPһWVӕ

c.1ҵPErQWUiLPһWVӕ

Giáo trình đo lường điện - Phần 1

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