Giáo trình đo lường điện - Phần 1

'R FҩX WҥR FӫD F{QJ Wѫ FXӝQ GzQJ ÿLӋQ Gk\ WR tW YzQJ Yj FXӝQ ÿLӋQ iS Gk\ QKӓ QKLӅXYzQJKѫQQrQNKLGQJ2KPNӃÿӇÿRNLӇPVӁÿѭӧFNӃWTXҧ5 DÒNG << R ÁP. Chú ý: 0XӕQSKpSÿRÿѭӧFFKtQK[iFNKLÿRSKҧLK[r]

(1)

(2)

http://www.ebook.edu.vn

B͡môn Cung C̭SĈL͏n Trang 5

&+ѬѪ1*,

ĈҤ,&ѬѪ1*9ӄĈ2/ѬӠ1*Ĉ,ӊ1 *LӟLWKLӋX

ROQJOjVVRViQKLOQJFKDELWLOQJRYLLOQJmF FKXQKyDLOQJPXKRFLOQJFKXQ

1KY\F{QJYLFROQJOjQLWKLWERYjRKWKQJFNKRViWYjTXan ViWNWTXRFFiFLOQJFQWKLWWUrQWKLWER7URQJWKFWUWNKy[iFQK àảWUVWKFảảFDLOQJR9uY\WUVRFFKRELWKLWERJLOjWUVWLQ Fk\FH[SHFWHGYDOXH

%WNLOQJRQjRFQJEQK KQJELQKLXWK{QJV'RyNWTXRtW NKLSKҧQiQKÿ~QJWUӏVӕWLQFұ\ÿѭӧF&KRQrQFyQKLӅXKӋVӕҧQKKѭӣQJWURQJÿROѭӡQJ OLrQTXDQÿӃQWKLӃWEӏÿR1JRjLUDFyQKӳQJKӋVӕNKiFOLrQTXDQÿӃQFRQQJѭӡLVӱGөQJ WKLӃWEӏÿR1KѭYұ\ÿӝFKtQK[iFFӫDWKLӃWEӏÿRÿѭӧFGLӉQWҧGѭӟLKLQKWKӭFVDLVӕ

1.1.KiLQLӋPYӅÿROѭӡQJÿLӋQ

7URQJWKӵFWӃFXӝFVӕQJTXiWUuQKFkQÿRÿRQJÿӃPGLӉQUDOLrQWөFYӟLPӑLÿӕL WѭӧQJ YLӋF FkQ ÿR ÿRQJ ÿӃP Qj\ Y{ FQJ FҫQ WKLӃW Yj TXDQ WUӑQJ 9ӟL PӝW ÿӕL WѭӧQJFөWKӇQjRÿyTXiWUuQKQj\GLӉQUDWKHRWӯQJÿһFWUѭQJFӫDFKӫQJORҥLÿyYj YӟLPӝWÿѫQYӏÿmÿѭӧFÿӏQKWUѭӟF

7URQJOƭQKYӵFNӻWKXұWÿROѭӡQJNK{QJFKӍWK{QJEiRWUӏVӕFӫDÿҥLOѭӧQJFҫQÿR PjFzQOjPQKLӋPYөNLӇPWUDÿLӅXNKLӇQYj[ӱOêWK{QJWLQ

ĈӕL YӟL QJjQK ÿLӋQ YLӋF ÿR OѭӡQJ FiF WK{QJ Vӕ FӫD PҥFK ÿLӋQ Oj Y{ FQJ TXDQ WUӑQJ1yFҫQWKLӃWFKRTXiWUuQKWKLӃWNӃOҳSÿһWNLӇPWUDYұQKjQKFǊQJQKѭGzWuPKѭ KӓQJWURQJPҥFKÿLӋQ

ĈROѭӡQJOjTXiWUuQKVRViQKÿҥLOѭӧQJFKѭDELӃWYӟLÿҥLOѭӧQJÿmELӃWFQJ ORҥLÿѭӧFFKӑQOjPPүXPүXQj\ÿѭӧFJӑLOjÿѫQYӏ

6ӕÿROjNӃWTXҧFӫDTXiWUuQKÿRNӃWTXҧQj\ÿѭӧFWKӇKLӋQEҵQJPӝWFRQVӕ FөWKӇ

'өQJFөÿR YjPүXÿR: D'өQJFөÿR

&iFGөQJFөWKӵFKLӋQYLӋFÿRÿѭӧFJӑLOjGөQJFөÿRQKѭGөQJFөÿRGzQJÿLӋQ $PSHPpWGөQJFөÿRÿLӋQiS9{QPpWGөQJFөÿRF{QJVXҩW2iWPpWYY

(3)

- /RҥLOjPPүXGQJÿӇNLӇPWUDFiFPүXÿRYjGөQJFөÿRNKiFORҥLQj\ÿѭӧF FKӃWҥRYjVӱGөQJWKHRWLrXFKXҭQNӻWKXұWÿҧPEҧROjPYLӋFFKtQK[iFFDR

- /RҥLF{QJWiFÿѭӧFVӱGөQJÿROѭӡQJWURQJWKӵFWӃORҥLQj\JӗPQKyPVDX 0үXÿRYjGөQJFөÿRWKtQJKLӋP

0үXÿRYjGөQJFөÿRGQJWURQJVҧQ[XҩW &iFSKѭѫQJSKiSÿR ÿѭӧFFKLDOjPORҥL

D3KѭѫQJSKiSÿRWUӵFWLӃS OjSKѭѫQJSKiSÿRPjÿҥLOѭӧQJFҫQÿRÿѭӧFVRViQK WUӵFWLӃSYӟLPүXÿR

3KѭѫQJSKiSQj\ÿѭӧFFKLDWKjQKFiFKÿR - 3KѭѫQJSKiSÿRÿӑFVӕWKҷQJ

- PKѭѫQJSKiSÿRVRViQKOjSKѭѫQJSKiSPjÿҥLOѭӧQJFҫQÿRÿѭӧFVRViQKYӟL PүXÿRFQJORҥLÿmELӃWWUӏVӕ

9tGͭ:

'QJFҫXÿRÿLӋQÿӇÿRÿLӋQWUӣGQJFҫXÿRÿӇÿRÿLӋQGөQJYY

E3KѭѫQJSKiSÿRJLiQWLӃS ljSKѭѫQJSKiSÿRWURQJÿyÿҥLOѭӧQJFҫQÿRVӁÿѭӧF WtQKUDWӯNӃWTXҧÿRFiFÿҥLOѭӧQJNKiFFyOLrQTXDQ

9tGͭ:

0XӕQÿRÿLӋQiSQKѭQJWDNK{QJFy9{QPpWWDÿRÿLӋQiSEҵQJFiFK - 'QJÐPPpWÿRÿLӋQWUӣFӫDPҥFK

- 'QJ$PSHPpWÿRGzQJÿLӋQÿLTXDPҥFK

6DXÿyiSGөQJFiFF{QJWKӭFKRһFFiFÿӏQKOXұWÿmELӃWÿӇWtQKUDWUӏVӕÿLӋQiSFҫQ ÿR

6DLVӕYjWtQKVDLVӕ 6DLVӕ

.KLÿRVӕFKӍFӫDGөQJFөÿRFǊQJQKѭNӃWTXҧWtQKWRiQOX{QFyVӵVDLOӋFKYӟLJLi WUӏWKӵFFӫDÿҥLOѭӑQJFҫQÿR/ѭӧQJVDLOӋFKQj\JӑLOjVDLVӕ

6DLVӕJӗPORҥL

6DLV͙K͏WK͙QJ OjVDLVӕFѫEҧQPjJLiWUӏFӫDQyOX{QNK{QJÿәLKRһFWKD\ÿәL FyTX\OXұW6DLVӕQj\YӅQJX\rQWҳFFyWKӇORҥLWUӯÿѭӧF

Nguyên nhân:

'RTXiWUuQKFKӃWҥRGөQJFөÿRQKѭPDViWNKҳFYҥFKWUrQWKDQJÿRYY

6DLV͙QJ̳XQKLrQ OjVDLVӕPjJLiWUӏFӫDQyWKD\ÿәLUҩWQJүXQKLrQGRVӵWKD\ ÿәL FӫD P{L WUѭӡQJ ErQ QJRjL QJѭӡL Vӱ GөQJ QKLӋW ÿӝ P{L WUѭӡQJ WKD\ ÿәL FKӏX ҧQK KѭӣQJFӫDÿLӋQWUѭӡQJWӯWUѭӡQJÿӝҭPiSVXҩWYY

Nguyên nhân:

(4)

B͡môn Cung C̭SĈL͏n Trang 7 - 'QJF{QJWKӭFWtQKWRiQNK{QJWKtFKKӧSGQJF{QJWKӭFJҫQÿ~QJWURQJWtQK WRiQ1KLӋWÿӝP{LWUѭӡQJWKD\ÿәLFKӏXҧQKKѭӣQJFӫDÿLӋQWUѭӡQJWӯWUѭӡQJÿӝҭPiS VXҩWYY

3KѭѫQJSKiSKҥQFKӃVDLVӕ

ĈӇKҥQFKӃVDLVӕWURQJWӯQJWUѭӡQJKӧSFyFiFSKѭѫQJSKiSVDX

ĈӕL YӟL VDL Vӕ KӋ WKӕQJ WLӃQ KjQK ÿR QKLӅX OҫQ Yj Oҩ\ JLi WUӏ WUXQJ EuQK FӫD chúng ĈӕLYӟLVDLVӕQJүXQKLrQQJѭӡLVӱGөQJFөÿRSKҧLFҭQWKұQYӏ WUtÿһWPҳWSKҧL YX{QJJyFYӟLPһWÿӝVӕFӫDGөQJFөWtQKWRiQSKҧLFKtQK[iFVӱGөQJF{QJWKӭFSKҧL WKtFKKӧSÿLӅXNLӋQVӱGөQJSKҧLSKKӧSYӟLÿLӅXNLӋQWLrXFKXҭQ &iFKWtQKVDLVӕ *͕L$NӃWTXҧÿRÿѭӧF

A1JLiWUӏWKӵFFӫDÿҥLOѭӧQJFҫQÿR

7tQKVDLV͙QK˱VDX 6DLVӕWX\ӋWÿӕL

'A =~A1- A~ (1.1)

'$JӑLOjVDLVӕWX\ӋWÿӕLFӫDSKpSÿR 6DLVӕWѭѫQJÿӕL % 100 A A A '

' KRһF *100%

1

A A

A '

' (1.2)

3KpSÿRFy'$FjQJQKӓWKuFjQJFKtQK[iF 6DLVӕTXLÿәLJTÿ

% 100 dm qd A A '

J *100%

dm

A A A

(1.3)

AÿPJLӟLKҥQÿRFӫDGөQJFөÿRJLiWUӏOӟQQKҩWFӫDWKDQJÿo) 4XDQKӋJLӳDVDLVӕWѭѫQJÿӕLYjVDLVӕTXLÿәL

d dm

dm

qd A K

A A A A A A * * % 100 ' ' ' J (1.4) dm d A A

K OjKӋVӕVӱGөQJWKDQJÿR.dd1)

1ӃX.d FjQJJҫQEҵQJWKuÿҥLOѭӧQJÿRJҫQEҵQJJLӟLKҥQÿR'A bé phép ÿRFjQJFKtQK[iF7K{QJWKѭӡQJSKpSÿRFjQJFKtQK[iFNKL.d t1/2

9tGө 0ӝWGzQJÿLӋQFyJLiWUӏWKӵFOj$'QJ$PSHPpWFyJLӟLKҥQÿR$ÿӇ ÿRGzQJÿLӋQQj\.ӃWTXҧÿRÿѭӧF$

7tQKVDLVӕWX\ӋWÿӕLVDLVӕWѭѫQJÿӕLVDLVӕTXLÿәL *LҧL

(5)

'A =~A1- A~= - 4,95 = 0,05 A 6DLVӕWѭѫQJÿӕL

% 100 A

A A '

' KRһF 100% 1%

5 05 , % 100 ' '

A A A

6DLVӕTXLÿәL

% , % 100 * 10

05 , % 100 '

dm qd

A A

J

%LӉXGLӉQVӕÿR

.ӃWTXҧÿRÿѭӧFELӇXGLӉQGѭӟLGҥQJ

0 X

X

A ta có X = A.X0 (1.5)

9tGө , $WKuĈҥLOѭӧQJÿROjGzQJÿLӋQ, ĈѫQYӏÿROj$PSH$ &RQVӕNӃWTXҧÿROj +ӋÿѫQYӏÿR

*LӟLWKLӋXKӋ6, 6\VWqPH,QWHUQDWLRQDOG8QLWpVKӋWKӕQJÿѫQYӏÿROѭӡQJ WK{QJGөQJQKҩWKӋWKӕQJQj\TXLÿӏQKFiFÿѫQYӏFѫEҧQFKRFiFÿҥLOѭӧQJVDX

- ĈӝGjLWtQKEҵQJPpWP

- KӕLOѭӧQJWtQKEҵQJNLO{JDPNJ - 7KӡLJLDQ WtQKEҵQJJLk\V - 'zQJÿLӋQWtQKEҵQJ$PSH$

%ӝLYjѭӟFVӕFӫDÿѫQYӏFѫ EҧQ

%ӝLVӕ ѬӟFVӕ

+ Tiga (T): 1012 + Mili (m): 10-3

+ Giga (G): 109 + Micro (P): 10-6

+ Mêga (M): 106 + Nano (n): 10-9

+ Kilô (K): 103 + Pico (p):10-12

7URQJÿy;OjÿҥLOѭӧQJÿR

(6)

B͡môn Cung CSLn Trang 9 &ặ8+,9ơ%ơ,73

A. &kXKLWUFQJKLP

FNFiFFkXKLFKQYjW{HQờWUOL~QJQKWYjRFiF{FiFFWWQJ ӭQJ

TT 1ӝLGXQJFkXKӓL a b c d

1.1. *LiWUӏEҵQJKLӋXVӕJLӳDJLiWUӏÿ~QJFӫDÿҥLOѭӧQJFҫQ ÿRYjJLiWUӏÿRÿѭӧFWUrQPһWÿӗQJKӗÿRÿѭӧFJӑLOj

a 6DLVӕSKө b 6DLVӕFѫEҧQ c 6DLVӕWX\ӋWÿӕL G6DLVӕWѭѫQJÿӕL

#ð #ð #ð #ð

1.2 7ӹ OӋ JLӳD VDL Vӕ WX\ӋW ÿӕL Yj JLi WUӏ WKӵF FҫQ ÿR WtQK WKHRÿѭӧFJӑLOj

a 6DLVӕWѭѫQJÿӕL b 6DLVӕSKө c 6DLVӕFѫEҧQ

d 7ӹOӋSKҫQWUăPFӫDVDLVӕWX\ӋWÿӕL

#ð #ð #ð #ð

1.3 .KLÿRÿLӋQiS[RD\FKLӅX9YӟLGөQJFөÿRFyVDLVӕ

WѭѫQJÿӕLWKuVDLVӕWX\ӋWÿӕLOӟQQKҩWFyWKӇFyYӟL GөQJFөOj

a 10V; b 2,2V; c 3,3V; d 1,1V

#ð #ð #ð #ð

%%jLWұS

1.4.1rXFiFÿӏQKQJKƭDYӅÿROѭӡQJ

1.53KѭѫQJSKiSÿROjJu"&yPҩ\SKѭѫQJSKiSÿR"

1.6ĈѫQYӏÿROjJu"7KӃQjRJӑLOjÿѫQYӏWLrXFKXҭQ"

1.7'өQJFөÿROjJu"

(7)

http://www.ebook.edu.vn &+ѬѪ1*,,

0Ӝ76Ӕ&Ѫ&Ҩ8Ĉ2&+ӌ7+ӎ.,0 *LӟLWKLӋX

+LӋQQD\NKRDKӑFNӻWKXұWUҩWSKiWWULӇQ1JѭӡLWDÿmFKӃWҥRUDÿѭӧFQKLӅXWKLӃWEӏ ÿROѭӡQJÿLӋQWӱFKӍWKӏNӃWTXҧÿREҵQJKLӋQVӕFyÿӝFKtQK[iFFDR7X\QKLrQFiFWKLӃW EӏÿROѭӡQJVӱGөQJFѫFҩXFKӍWKӏNӃWTXҧÿREҵQJNLPYүQÿѭӧFVӱGөQJUҩWSKәELӃQ WURQJFiF[tQJKLӋSWUѭӡQJKӑFFǊQJQKѭWURQJFiFSKzQJWKtQJKLӋPYuWtQKѭXYLӋWFӫD Qy&iFWKLӃWEӏÿROѭӡQJVӱGөQJFѫFҩXÿRFKӍWKӏNLPÿѭӧFGQJQKLӅXQKҩWOj9{QPpW Yj$PSHPpWKѫQWKӃQӳDFiFFѫFҩXQj\WKDRWiFVӱGөQJÿѫQJLҧQYjJLiWKjQKFǊQJ UҿKѫQUҩWQKLӅXVRYӟLFiFWKLӃWEӏÿROѭӡQJFKӍWKӏNӃWTXҧÿROѭӡQJEҵQJKLӋQVӕ9uYұ\ QJѭӡLF{QJQKkQFҫQKLӇXU}FҩXWҥRQJX\rQOêKRҥWÿӝQJFǊQJQKѭVӱGөQJWKjQKWKҥR FiFFѫFҩXÿRFKӍ WKӏNLP

1JX\rQWҳFFKXQJFӫDFiFORҥLPi\ÿRFKӍWKӏNLP

+LӋQQD\WDFKӍKӑFFiFFѫFҩXFKӍWKӏNӃWTXҧÿREҵQJNLPFzQFiFFѫFҩXFKӍWKӏ NӃWTXҧÿREҵQJVӕÿѭӧFÿӅFұSWURQJSKҫQWKLӃWEӏÿROѭӡQJFKӍWKӏVӕ

ĈӕLYӟLFiFFѫFҩXFKӍWKӏNLPNKLWKӵFKLӋQPӝWSKpSÿROX{QWXkQWKHRWUuQKWӵ sau:

7tQKLӋXFӫDÿҥLOѭӧQJFҫQÿRÿѭӧFÿѭDYjRPҥFKÿRYjÿѭӧFELӃQÿәLWKjQKÿҥL OѭӧQJÿLӋQÿҥLOѭӧQJÿLӋQQj\ÿѭӧFÿѭDYjRFѫFҩXÿRYjNӃWTXҧÿRÿѭӧFÿѭDUDNKӕL FKӍWKӏVѫÿӗÿѭӧFKuQKWKjQK

2.1.1 SѫÿӗNKӕL

+uQK6ѫÿӗNKӕLFӫDFѫFҩXÿR

&KX\ӇQÿәLVѫFҩSOjPQKLӋPYөELӃQÿәL FiFÿҥLÿRWKjQKWtQKLӋXÿLӋQ ĈyOjNKkXTXDQWUӑQJQKҩWFӫDWKLӃWEӏÿR

0ҥFKÿROjNKkXJLDF{QJWK{QJWLQÿRVDXFKX\ӇQÿәLVѫFҩSOjPQKLӋP YөWtQKWRiQYjWKӵFKLӋQWUrQVѫÿӗPҥFK0ҥFKÿRWKѭӡQJOjPҥFKÿLӋQWӱYL[ӱOêÿӇ QkQJFDRÿһFWtQKFӫDGөQJFө ÿR

&ѫFҩXFKӍWKӏÿROjNKkXFXӕLFQJFӫDGөQJFөWKӇKLӋQNӃWTXҧÿRGѭӟL GҥQJFRQVӕYӟLÿѫQYӏ

&yFiFKWKӇKLӋQNӃWTXҧÿR + &KӍWKӏEҵQJNLP

&KӍWKӏEҵQJWKLӃWEӏWӵJKL + &KӍWKӏGѭӟLGҥQJFRQVӕ

1KѭYұ\FѫFҩXÿREDRJӗPFySKҫQWƭQKYjSKҫQÿӝQJ

(8)

B͡môn Cung C̭SĈL͏n Trang 11 3KҫQWƭQKFyQKLӋPYөELӃQÿәLÿLӋQQăQJÿѭDYjRWKjQKFѫQăQJWiFGөQJ OrQSKҫQÿӝQJ

3KҫQ ÿӝQJ JҳQ OLӅQ YӟL NLP JyF TXD\ FӫD NLP [iF ÿӏQK WUӏ Vӕ FӫD ÿҥL OѭӧQJÿѭӧFÿѭDYjRFѫFҩXÿR

.KӕLFKӍWKӏ 2.1.2 Nguyên lý:

9ӟLFiFORҥLPi\ÿR FKӍWKӏNLPQrXWUrQWX\YӅFҩXWU~FFyNKiFQKDXQKѭQJFK~QJ FyFKXQJPӝWQJX\rQWҳFVDX

.KLGzQJÿLӋQFKҥ\WURQJWӯWUѭӡQJVӁVLQKUDPӝWOӵFÿLӋQWӯ OӵFQj\VӁVLQKUD PӝWP{PHQTXD\OjPTXD\NLPFKӍWKӏPӝWJyFD, góc quay D FӫDNLPOX{QWӹOӋYӟLÿҥL OѭӧQJFҫQÿREDQÿҫXQrQQJѭӡLWDVӁÿRJyFOӋFKQj\ÿӇELӃWJLiWUӏFӫDÿҥLOѭӧQJFҫQÿR &ѫFҩXÿRNLӇXWӯÿLӋQ

2.2.1 .êKLӋX

2.2.2 6ѫÿӗFҩXWҥR

.KXQJTXD\NKXQJTXD\EҵQJQK{PKuQKFKӳQKұWWUrQNKXQJ FyTXҩQGk\ÿӗQJ EӑF YHFQL 7RjQ Eӝ NKӕL OѭӧQJ NKXQJ TXD\ SKҧL FjQJ QKӓ FjQJ WӕW ÿӇ VDR FKR P{PHQ TXiQWtQKFjQJQKӓFjQJWӕW7RjQEӝNKXQJTXD\ÿѭӧFÿһWWUrQWUөFTXD\KRһFWUHREӣL dây treo

1DP FKkP YƭQK FӱX NKXQJ TXD\ ÿѭӧF ÿһW JLӳD KDL FӵF Wӯ 1-S FӫD QDP FKkP YƭQKFӱX

Hình 2.2a: Ký hiӋXFѫFҩu tӯ ÿLӋn Hình 2.2b: Ký hiӋXFѫFҩu tӯ ÿLӋn

N S

Khe hӣcӵc tӯ

Lӓi sҳt non

Ĉӕi trӑng Cuӝn dây

Nam châm

Cӵc tӯ

Kim chӍthӏ

Lò xo x

(9)

http://www.ebook.edu.vn /}LVҳWQRQKuQKWUөQҵPWURQJNKXQJTXD\WѭѫQJÿӕLÿӅX

.LPFKӍWKӏÿѭӧFJҳQFKһWWUrQWUөFTXD\KRһFGk\WUHR3KtDVDXNLPFKӍWKӏFy PDQJÿӕLWUӑQJÿӇVDRFKRWUӑQJWkPFӫDNLPFKӍWKӏQҵPWUrQWUөFTXD\KRһFGk\WUHR

+ 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 D (2.8)

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 ³T

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)

http://www.ebook.edu.vn &+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{QJVXҩWPA I2Rm 7ӯÿyÿӇSKpSÿRÿѭӧFFKtQK[iFWKu RmSKҧLUҩWQKӓ

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

7ӯÿyWD[iFÿӏQKÿѭӧFF{QJVXҩWWLrXWKөWUrQWҧLWKHRF{QJWKӭFWUrQ 1KѭӧFÿLӇP:

&KұPFyNӃWTXҧYuSKҧLTXDTXiWUuQKWtQKWRiQWUXQJJLDQ &ҫQSKҧLFyGөQJFөÿR

6DLVӕWѭѫQJÿӕLOӟQ

>6DLVӕSKpSÿR VDLVӕ$PSHPpWVDLVӕ9{QPpWVDLVӕWtQKWRiQ@ - ĈRWUӵFWLӃS

ĈӇÿRF{QJVXҩWWUӵFWLӃSWDGQJGөQJFөÿROj2iWPpW

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

UDC

+

-+ +

-R V

(29)

2iWPpWWKѭӡQJÿѭӧFFKӃWҥRWӯFѫFҩXÿRÿLӋQÿӝQJKRһFVҳWÿLӋQÿӝQJĈk\OjKDL FѫFҩXÿRYӯDÿRÿѭӧF,AC IDC2iWPpWJӗPKDLFXӝQGk\

&XӝQGk\WƭQKFyVӕYzQJtWGQJGk\FyWLӃWGLӋQOӟQYjÿѭӧFPҳFQӕLWLӃS YӟLPҥFKFҫQÿRF{QJVXҩWJӑLOjFXӝQGzQJ

&XӝQGk\ÿӝQJÿѭӧFTXҩQQKLӅXYzQJYӟLWLӃWGLӋQGk\QKӓFyÿLӋQWUӣQKӓ ÿѭӧFPҳFQӕLWLӃSYӟLÿLӋQ WUӣSKө5p YjVRQJVRQJYӟLPҥFKFҫQÿRF{QJVXҩWJӑLOj FXӝQiS

7UrQWKDQJÿRQJѭӡLWDJKLWKҷQJWUӏVӕF{QJVXҩWWѭѫQJӭQJYӟLJyFTXD\D

.KLÿәLFKLӅXGzQJÿLӋQFӫDPӝWWURQJKDLFXӝQGk\P{PHQTXD\VӁÿәLFKLӅXGR ÿyNLPFӫD2iWPpWVӁTXD\QJѭӧFOҥL7tQKFKҩWÿyJӑLOjFӵFWtQKFӫD2iWPpW

ĈӇWUiQKPҳFQKҫPFӵFWtQKFiFÿҫXFXӝQGk\FQJQӕLYӟLÿҫXQJXӗQÿѭӧFÿiQK GҩXKRһF&ҫQFK~êÿLӅXQj\NKLVӱGөQJ2iWPpW

ĈRF{QJVXҩWWiFGөQJPҥFK[RD\FKLӅXPӝWSKDEDSKD DĈRF{QJVXҩWWURQJPҥFKÿLӋQ[RD\FKLӅXSKD

9ӟL PҥFK ÿLӋQ [RD\ FKLӅX NK{QJ WKӇ GQJ SKѭѫQJ SKiS $PSHPpW- 9{QPpW ÿӇ [iFÿӏQKF{QJVXҩWWLrXWKөWUrQWҧLYuWtFKVӕ8,FKӍOjF{QJVXҩWELӇXNLӃQPjSKҧLGQJ 2iWPpWÿӇÿR

7DELӃWUҵQJJyFTXD\D WURQJWUѭӡQJKӧSQj\WӍOӋYӟLFiFGzQJÿLӋQ,GzQJÿLӋQ TXDWҧLYj,vGzQJÿLӋQTXDFXӝQÿӝQJWӍOӋYӟLÿLӋQiSWҧLTXDFXӝQGk\YjJyFOӋFK SKDJLӳDFK~QJ9uÿLӋQFҧPWURQJFXӝQiSNK{QJÿiQJNӇQrQGzQJÿLӋQ,v U SKD9ұ\JyFOӋFKSKDJLӳDGzQJÿLӋQ,Yj,v FǊQJFKtQKOjJyFOӋFKSKDM JLӳDGzQJ ÿLӋQ,YjÿLӋQiSSKөWҧL8'RÿyWDFy

P K P R R

K UI

R R

K

p u p

u

1

cos

M

D

7URQJÿy (

P UR

R K K1 )

+uQKĈRcông suҩt mӝt chiӅu bҵng Oatmét Iv

RP Rt

I

1 *

*

+

-UDC

(30)

%͡P{Q&XQJ&̭SĈL͏Q Trang 33 1JKƭDOjJyFTXD\FӫDNLPWӹOӋYӟLF{QJVXҩWFҫQÿR'Rÿy2iWPpWNLӇXÿLӋQÿӝQJ Yj VҳW ÿLӋQ ÿӝQJ Fy WKӇ GQJ ÿӇ ÿR F{QJ VXҩW WURQJ FiF PҥFK ÿLӋQ PӝW FKLӅX Yj [RD\ FKLӅX

.KLVӱGөQJ2iWPpWSKҧLFK~êÿӃQFӵFWtQKFӫDFXӝQGk\9uNKLÿәLFKLӅXGzQJ ÿLӋQWURQJFXӝQGk\WKuP{PHQTXD\ÿәLFKLӅXGүQÿӃQNLPFӫD2iWPpWTXD\QJѭӧF

- &iFKÿҩX2iWPpWYjRPҥFKFyFiFK

ĈҩXFXӝQGzQJÿLӋQWURQJKuQKDGQJNKLÿRPҥFKÿLӋQFyF{QJVXҩWQKӓ ĈҩXFXӝQGzQJÿLӋQQJRjLGQJNKLÿRPҥFKÿLӋQFyF{QJVXҩWOӟQ

- 7KD\ÿәLWҫPÿR

ĈӕLYӟL FXӝQGzQJÿLӋQQJѭӡLWDFKLDFXӝQGzQJFXӝQWƭQKWKjQKKDLQӱDFXӝQ UӗLÿҩXQӕLWLӃSKRһFVRQJVRQJOҥLYӟLQKDX

.KLÿҩXQӕLWLӃSKDLQӱDFXӝQKuQKDWҫPÿROj,ÿP .KLÿҩXVRQJVRQJKDLQӱDFXӝQKuQKEWҫPÿROj,ÿP

ĈӕLYӟLFXӝQÿLӋQiSGQJÿLӋQWUӣSKөQKLӅXFӣÿӇWKD\ÿәLWҫPÿRQKѭ9{Q PpWPҳFQӕLWLӃSFiFÿLӋQWUӣSKөYjRFXӝQÿӝQJPҥFKQKѭKuQKF

+uQKĈRF{QJVXҩt xoay chiӅu bҵng Oátmét

*

Iv

RP Rt

I

1

*

UAC

Ru

a CuӝQÿLӋn áp mҳFWUѭӟc *

Iv

RP Rt

I

1

*

UAC

Ru

*

Iv

RP Rt

I

1

*

UAC

Ru

Hình 3.19: Hai cách nӕi Oátmét

(31)

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

-0ҥFKSKDGk\

ĈӇÿRF{QJVXҩWӣ PҥFKSKDGk\QJѭӡL WDGQJ 2iWPpWSKDPӛL2iWPpW PҳFYjRPӝWSKDVDXÿyFӝQJFiFFKӍVӕFӫDFK~QJOҥLYӟLQKDX

P3P= P1 +P2 + P3

7URQJWKӵFWӃQJѭӡLWDFKӃWҥR2iWPpWSKDSKҫQWӱ1yEDRJӗPFXӝQGzQJ ÿLӋQWѭѫQJӭQJYӟL FXӝQÿLӋQiSJҳQWUrQFQJPӝWWUөFTXD\0{PHQOjPTXD\SKҫQ ÿӝQJOjWәQJFӫDP{PHQWKjQKSKҫQ7ӭFOjVӕFKӍFӫD2iWPpWVӁWӹOӋYӟLF{QJVXҩW pha

3KѭѫQJWUuQKÿһFWtQKWKDQJÿR D K3P3P

6ѫÿӗPҳFQKѭVDX

+uQK7KD\ÿәi cӥ ÿRFӫa Oátmét IÿP

IÿP

a

2IÿP

IÿP

b

*

Iv

RP1 R

t I

2 *

UAC

Ru

1

3 RP2

RP3

c

A

ZA ZB ZC

* P1

* *

*

P2

P3 B

C N

+uQK6ѫÿӗdùng Oátmét mӝt pha

ҩ

A

ZA ZB ZC

* P1

* *

* P2

P3 B

C N

Hình 3.22: 6ѫÿӗdùng Oátmét ba pha ba phҫn tӱ

(32)

%͡P{Q&XQJ&̭SĈL͏Q Trang 35 - 0ҥFKSKDGk\

*ӑLGzQJÿLӋQFKҥ\WURQJSKDOҫQOѭӧWOjLA, iB, iCta có:

iA+ iB+ iC= iC= -(iA+iB) &{QJVXҩWWӭFWKӡLSKD

P3P = iAUA+iBUB+ iCUC = iAUA+ iBUB- (iA+iB)UC

= iA(UA- UC) + iB(UB- UC) = iAUAC+iBUBC

= P1+ P2

1KѭYұ\F{QJVXҩWFӫDPҥQJSKDGk\ÿѭӧFÿR2iWPpWPӝWSKD 2iWPpWWKӭQKҩWÿRGzQJÿLӋQSKD$YjÿLӋQiS8AC

2iWPpWWKӭKDLÿRGzQJÿLӋQSKD%YjÿLӋQiS8BC 6ѫ ÿӗPҳF2iWPpWQKѭVDX

7URQJ WKӵF WӃ QJѭӡL WD FKӃ WҥR 2iWPpW SKD SKҫQ Wӱ QӕL FKXQJ PӝW WUөF FiFK PҳFGk\2iWPpWSKDQKѭFiFKPҳFӣSKѭѫQJSKiSÿRF{QJVXҩWPҥQJSKDEҵQJ 2iWPpWVӕFKӍFӫD2iWPpWQj\VӁOjF{QJVXҩWFӫDPҥQJSKDGk\

6ѫ ÿӗPҳF2iWPpWQKѭVDX

7UѭӡQJKӧSPҥQJSKDFkQEҵng:

1ӃXWUѭӡQJKӧSPҥQJSKDFkQEҵQJFK~QJWDFKӍFҫQGQJPӝW2iWPpWPӝWSKD ÿRF{QJVXҩWӣPӝWSKDVDXÿyOҩ\NӃWTXҧÿRÿѭӧFQKkQYӟLPҥFKSKDGk\KRһF QKkQYӟLPҥFKSKDGk\

A B C

Z Z

Z *

*

* * P2 P1

+uQK6ѫÿӗdùng Oátmét mӝt pha

ÿR F{QJ VXҩt mҥch ba pha ba dây

A B C

Z Z

Z *

*

* *

P2 P1

+uQK6ѫÿӗdùng Oátmét ba pha hai phҫn tӱ

(33)

7UѭӡQJ KӧS ÿm QӕL ÿ~QJ FӵF WtQK Pj NLP FӫD PӝW 2iWPpW QjR ÿy YүQ TXD\ QJѭӧFWKuSKҧLÿәLFKLӅXFXӝQGk\ÿLӋQiSFӫD2iWPpWҩ\/~FÿyF{QJVXҩWWiFGөQJFӫD PҥFKSKDVӁEҵQJKLӋXVӕFӫDVӕFKӍFӫD2iWPpWWӭFOj

P3p= P1 - P2

&KRQrQWDQyLUҵQJF{QJVXҩWFӫDPҥQJSKD EҵQJWәQJÿҥLVӕVӕFKӍFӫD2iWPpW ĈRKӋVӕF{QJVXҩW

+ӋVӕF{QJVXҩWFRVM FӫDPҥFKÿLӋQ[RD\FKLӅXGQJÿӇÿiQKJLiFKҩWOѭӧQJFӫD PҥFKÿLӋQ7URQJÿyMOjJyFOӋFKSKDJLӳDÿLӋQiSYjGzQJÿLӋQ

ĈRKӋVӕF{QJVXҩWEҵQJSKѭѫQJSKiSJLiQWLӃS - 7KHRF{QJWKӭFWtQKF{QJVXҩWWDFy

P = UIcosM

UI P

cosM

9ұ\GQJFiFGөQJFөÿR2iWPpWY{QPpWYjDPSHPpW - 9ӟLPҥFKSKDÿӕL[ӭQJ

P 3UdId cosM

d dI U P cos M

- 9ӟLPҥFKSKDNK{QJÿӕL[ӭQJFRVM FӫDSKDNK{QJEҵQJQKDXQrQFyNKiL QLӋPFRVM FӫDPҥFKSKDQKѭVDX

7ӯWDPJLiFF{QJVXҩWWDFy

P Q

tgM mà

M M 1 cos tg nên ) ( 1 cos P Q M 9ӟLKӝWLrXWKөÿLӋQQăQJ A ZA ZB ZC * P * B C N

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

2 ) (

1 cos

TD PK

W W

M

7URQJÿy

WPKÿLӋQQăQJSKҧQNKiQJÿREҵQJGөQJFөÿӃPÿLӋQQăQJSKҧQNKiQJF{QJ WѫSKҧQNKiQJ

WTDÿLӋQQăQJWiFGөQJÿREҵQJGөQJFөÿӃPÿLӋQQăQJWiF GөQJF{QJWѫ ÿLӋQ

ĈRKӋVӕF{QJVXҩWÿӑFWKҷQJ

'өQJFөÿRKӋVӕF{QJVXҩWÿӑFWKҷQJOjFRVM NӃFRVM NӃÿLӋQÿӝQJSKDFyFѫ FҩXÿROjWӹVӕNӃÿLӋQÿӝQJFyPҥFKPҳFQKѭKuQKYӁ

&XӝQGk\SKҫQWƭQKFӫDWӹVӕNӃOjFXӝQGzQJÿLӋQFyGzQJÿLӋQFӫDSKөWҧLÿLTXD FXӝQGk\ÿLӋQiSÿѭӧFFKLDWKjQKFXӝQÿѭӧFÿһWGѭӟLÿLӋQiS8WURQJÿyPӝWFXӝQ ÿѭӧFQӕLWLӃSYӟLÿLӋQWUӣSKө5P OӟQQrQGzQJ,1 TXDFXӝQGk\WUQJSKDYӟLÿLӋQiS 8FXӝQGk\QӕLWLӃSYӟLFXӝQFҧP/FyÿLӋQFҧPOӟQ, nên dòng I2 TXDFXӝQGk\FKұP SKDVDXVRYӟLÿLӋQiS8PӝWJyF0

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

Rt L

U

I1 R

* *

+uQK6ѫÿӗnguyên lý cӫa cosM kӃ ÿLӋQÿӝng

(35)

- 3KҫQWƭQK

*ӗPFyQDPFKkPÿLӋQFKӳ*QDPFKkPGzQJÿLӋQFKӳ8YjPӝWQDPFKkPYƭQK FӱXOjPEӝFҧQGӏX

1DPFKkPÿLӋQFKӳ*TXҩQGk\FӣQKӓVӕYzQJQKLӅXQӕLVRQJVRQJYӟLPҥFK FҫQÿROjPFXӝQiS

1DPFKkPGzQJÿLӋQFKӳ8TXҩQVӕYzQJGk\tWWLpWGLӋQGk\OӟQOjPFXӝQGzQJ YjÿѭӧFPҳFQӕLWLӃSYӟLPҥFKFҫQÿR

1DPFKkPYƭQKFӱXÿӇWҥRUDP{PHQFҧQ - 3KҫQÿӝQJ

/jPӝWÿƭDQK{PWUzQӣWkPÿƭDFyJҳQWUөFTXD\PӝWÿҫXWUөFJҳQWUrQә ÿӣPӝWÿҫXFzQOҥLJҳQYӟLKӋWKӕQJEiQK[HUăQJFyFҩXWҥRÿһFELӋWWKHRWӹOӋÿӇ ÿӃPVӕYzQJTXD\FӫDÿƭDQK{PWKӇKLӋQWUrQEiQK[HFӫDWUөFVӕ

E1JX\rQOêOjPYLӋF

&{QJWѫÿLӋQOjPYLӋFWKHRQJX\rQOêFҧPӭQJÿLӋQWӯ

.KL Fy GzQJ ÿLӋQ [RD\ FKLӅX ÿL TXD FXӝQ GzQJ ÿLӋQ VӁ VLQK UD Wӯ WK{QJ)1 ELӃQ WKLrQTXDÿƭDQK{PGRÿyWURQJÿƭDQK{PVӁ[XҩWKLӋQGzQJ ÿLӋQ[Ri\Li7ѭѫQJWӵQKѭ Yұ\ӣFXӝQÿLӋQiSGzQJ[RD\FKLӅXVLQKUDWӯWK{QJ)2 ELӃQWKLrQGRÿyVLQKUDGzQJ

+uQK&{QJWѫÿLӋn pha Nam châm dòng

ÿLӋn chӳU

ÿƭDQK{P

Trөc quay (2) HӋthӕng bánh

[HUăQJ

Bánh xe trөc sӕ(4)

(36)

%͡P{Q&XQJ&̭SĈL͏Q Trang 39 ÿLӋQLѭ QJѭӧFFKLӅXYӟLLi dòng ii iѭ WiFGөQJYӟL)1 )2 WҥRWKjQKP{PHQ TXD\OjPÿƭDQK{PTXD\

Mq = K1 P

'RÿƭDQK{POҥLQҵP WURQJWӯWUѭӡQJFӫDQDPFKkPYƭQKFӱXQrQ NKLÿƭDQK{P TXD\WKuWURQJÿƭDOҥL[XҩWKLӋQGzQJFҧPӭQJLc6ӵWѭѫQJWiFJLӳDLcYjWӯWUѭӡQJFӫD QDPFKkPYƭQKFӱXVӁVLQKUDP{PHQKmPQJѭӧFFKLӅXYӟLP{PHQTXD\GRÿyQDP châmYƭQKFӱXFzQÿѭӧFJӑLOjQDPFKkPKmP

Mc= K2QQOjWӕFÿӝTXD\FӫDÿƭDQK{P

Khi Mq= Mc WKuÿƭDQK{PTXD\ÿӅX

Mq= Mc K1 P = K2n P K K K P

n 3

2

(

2

K K

K )

1KѭYұ\WӕFÿӝTXD\FӫDÿƭDQK{PWӹOӋYӟLF{QJVXҩW3FӫDPҥFKFҫQÿRF{QJ VXҩWTXDF{QJWѫÿLӋQ

ĈӇÿRÿLӋQQăQJWURQJPҥFK[RD\FKLӅXSKDFyWKӇGQJF{QJWѫSKDYӟL FiFKPҳFGk\WѭѫQJWӵQKѭNKLÿRF{QJVXҩWSKDEҵQJ2iWPpW&ǊQJFyWKӇGQJ F{QJWѫSKDÿӇÿRÿLӋQQăQJWURQJPҥFK[RD\FKLӅXSKD

&{QJWѫSKDJӗPFѫFҩXF{QJWѫSKDQӕLWUrQFQJPӝWWUөFTXD\QKѭKuQK 3.28:

+uQKF{QJWѫEDSKD

1DP FKkP ÿLӋQ [RD\ FKLӅX

1DP FKkP YƭQK FӱX QDP châm hãm)

ĈƭDQK{P

6

8

1,

(37)

3.5.3 &iFKPҳFF{QJWѫYjRPҥFKFҫQÿR:

ĈӕLYӟLF{QJWѫSKDKD\SKDÿӅXFyFӵFWtQKFӫDFiFFXӝQGzQJYjiSÿѭӧFÿiQK EҵQJGҩXGRÿyNKLPҳFGk\FҫQFK~êÿҩXÿ~QJÿҫXFӵFWtQK

- 6ѫÿӗÿҩXGk\F{QJWѫSKD+uQK

- 6ѫÿӗÿҩXGk\F{QJWѫSKDSKҫQWӱ+uQK

- tKLӋXTXLѭӟFF{QJWѫÿLӋQPӝWSKDÿѭDUDÿҫXGk\ÿѭӧFÿiQKVӕOҫQOѭӧWWӯ WUiLTXDSKҧLOjKD\66//

&iFÿҫXKD\66ÿѭӧFQӕLYӟLQJXӗQ &iFÿҫXKD\//ÿѭӧFQӕLYӟLWҧLWLrXWKө 3.5.4 &iFKFKӑQF{QJWѫKӧSOê:

7UrQF{QJWѫÿLӋQQKjVҧQ[XҩWVӁFKRFiFJLiWUӏ

ĈLӋQiSÿӏQKPӭF8ÿP OjJLiWUӏÿLӋQiSFKRSKpSF{QJWѫOjPYLӋF&{QJ WѫSKDWKѭӡQJFyÿLӋQiSÿӏQKPӭFOj9KRһF9&{QJWѫSKDWKѭӡQJFyÿLӋQ iSÿӏQKPӭFOjSKD9KRһFSKD9

'zQJÿLӋQÿӏQKPӭF,ÿPOjJLiWUӏGzQJÿLӋQOjPYLӋFFӫDF{QJWѫ1KjVҧQ [XҩWWKѭӡQJFKRJLiWUӏGzQJÿLӋQOjPYLӋFEuQKWKѭӡQJÿӏQKPӭFYjGzQJÿLӋQWӕLÿD FӵFÿҥLPjF{QJWѫFyWKӇOjPYLӋFÿѭӧFGѭӟLGҥQJ,ÿP(Imax)

Nguӗn Tҧi

L

N

* *

+uQK6ѫÿӗÿҩXGk\F{QJWѫSKD

Tҧi A

B C N

* *

(38)

%͡P{Q&XQJ&̭SĈL͏Q Trang 41 HҵQJVӕF{QJWѫFKR ELӃWVӕYzQJTXD\FӫDF{QJWѫWUrQPӛL.:KÿLӋQ QăQJ WLrX WKө 7K{QJ WKѭӡQJ Fy FiF KҵQJ Vӕ VDX 5HY.:K 5HY.:K Rev/KWh;1200 Rev/KWh

1JRjLUDWUrQQKmQFzQFyFiFWK{QJVӕNKiFQKѭWҫQVӕVӕKLӋXVҧQSKҭP QăPVҧQ[XҩW

4XDQViWFiFNêKLӋXWUrQPһWF{QJWѫÿӇFKӑQF{QJWѫWKtFKKӧSYӟLPҥFKFҫQ ÿRÿLӋQiSGzQJÿLӋQÿӏQKPӭFKҵQJVӕF{QJWѫFҩSFKtQK[iFYY

.KLFKӑQF{QJWѫQJRjLYLӋFFKӑQÿLӋQiSFӫDF{QJWѫWKtFKKӧSYӟLÿLӋQiSPҥFK FҫQÿRWDFҫQSKҧLFKӑQGzQJÿLӋQÿӏQKPӭFFӫDF{QJWѫWKtFKKӧSYӟLGzQJÿLӋQPҥFK ÿR0XӕQYұ\WDSKҧLWtQKFѭӡQJÿӝGzQJÿLӋQWӕLÿDFӫDWҩWFҧFiFÿӗGQJÿLӋQWURQJ QKj[HPQKѭWҩWFҧÿӗGQJÿLӋQQj\ÿѭӧFVӱGөQJFQJPӝWO~F

3.5.5. ĈRNLӇPF{QJWѫ

'R FҩX WҥR FӫD F{QJ Wѫ FXӝQ GzQJ ÿLӋQ Gk\ WR tW YzQJ Yj FXӝQ ÿLӋQ iS Gk\ QKӓ QKLӅXYzQJKѫQQrQNKLGQJ2KPNӃÿӇÿRNLӇPVӁÿѭӧFNӃWTXҧ5DÒNG<< RÁP Chú ý: 0XӕQSKpSÿRÿѭӧFFKtQK[iFNKLÿRSKҧLKӣFҫXQӕLWҥLÿLӇPVӕWUrQVѫÿӗ

3.5.6. .LӇPWUDVѫEӝWӕFÿӝTXD\FӫDF{QJWѫ

7ӕFÿӝTXD\FӫDF{QJWѫSKөWKXӝFYjR

ĈӝOӟQFӫDWҧLWҧLFjQJOӟQWӕFÿӝTXD\FjQJQKDQK

+ҵQJ Vӕ ÿӃP FӫD F{QJ Wѫ KҵQJ Vӕ Qj\ FjQJ FDR WӕF ÿӝ TXD\ VӁ FjQJ QKDQK Ĉk\OjWKDPVӕFѫEҧQÿӇFkQFKӍQKKRһFNLӇPWUDÿӝFKtQK[iFFӫDF{QJWѫ

9tGө

&{QJWѫÿLӋQORҥL9$5HY.:K.LӇPWUDF{QJWѫEҵQJEyQJÿqQ 220V± :WKuWKҩ\

*LҧVӱÿLӋQiSQJXӗQÿ~QJOj9YjF{QJVXҩWFӫDÿqQÿ~QJ:NK{QJVDL Vӕ

'RF{QJVXҩWFӫDÿqQOj:QrQSKҧLVӱGөQJKWKuOѭӧQJÿLӋQQăQJWLrX WKөPӟLOj.:K1JKƭDOjO~FÿyÿӗQJKӗTXD\ÿѭӧFYzQJ

1KѭYұ\WURQJJLӡF{QJWѫVӁTXD\ÿѭӧF YzQJKD\OjPӛLphút F{QJWѫVӁTXD\YzQJ

3.5.7 ĈӑFFKӍVӕYjWtQKÿLӋQQăQJWLrXWKө

.KLF{QJWѫOjPYLӋFOѭӧQJÿLӋQQăQJWLrXWKөVӁÿѭӧFKLӇQWKӏWUrQPһWVӕÿѫQYӏ WtQKOj.:K1JѭӡLGQJFKӍYLӋFÿӑFJLiWUӏQj\WKHRTXLѭӟFWӯWUiLVDQJSKҧL

7tQKÿLӋQQăQJWLrXWKөFӫDPӝWWKiQJ$tháng FKӍVӕPӟL± FKӍVӕFǊ

ĈѪ19ӎ CHӨC

75Ă0 NGÀN

CHӨC NGÀN

(39)

http://www.ebook.edu.vn 7+Ӵ&+¬1+Ĉ2&È&ĈҤ,/ѬӦ1*Ĉ,ӊ18,39¬$

ĈRÿLӋQ iSYjGzQJÿLӋQ 7UuQKWӵWKӵFKLӋQQKѭVDX

1. 'QJ Pi\ ÿR 920 ÿR NLӇP WUD FiF FҩS ÿLӋQ iS $& '& FӫD Eӝ QJXӗQ WKt QJKLӋP

2. /ҳSPҥFKQKѭKuQKVDX

3. ĈRGzQJÿLӋQTXDPҥFKFKtQK, %1ӕLWҳWF± d; c ±i

%&ҩSQJXӗQWҥLDYjJ±)

%7LӃQKjQKÿRGzQJÿLӋQWҥLEF±YjJKLNӃWTXҧYjREҧQJ

4. ĈRGzQJÿLӋQTXDPҥFKQKiQKWKӭQKҩW,1) 0ҥFKÿDQJӣWUҥQJWKiLQKѭSKҫQWLӃQKjQK %1ӕLWҳWE± c

%+ӣPҥFKWҥLF±d

%ĈRGzQJÿLӋQTXDPҥFKQKiQKWKӭQKҩW,1WҥLFG±), YjJKLNӃWTXҧYjR EҧQJ

5. ĈRGzQJÿLӋQTXDPҥFKQKiQKWKӭKDL,2)

7LӃQKjQKWѭѫQJWӵQKѭSKҫQ1ӕLWҳWF- GKӣPҥFKYjÿRWҥLFYjL-JKLNӃW TXҧYjREҧQJJKLNӃWTXҧÿR

&K~ê0XӕQÿRGzQJÿLӋQWҥLÿLӇPQjRWKuSKҧLKӣPҥFKYjÿRWҥL ÿLӇPÿy

6. ĈRVөWiSWUrQWӯQJQKiQKYjWӯQJSKҫQWӱ 0ҥFKÿDQJӣWUҥQJWKiLQKѭSKҫQWLӃQKjQK %1ӕLWҳWF± LQJXӗQYүQFҩSQKѭFǊ

%ĈRVөWiSWUrQWӯQJQKiQKWҥLFiFÿLӇPD±b; d ±f; f ±g; i ±h %ĈRVөWiSWUrQWӯQJÿLӋQWUӣWҥLFiFÿLӇPD±b; d ±e; e ±f; f ±g;

và i ± KJKLNӃWTXҧYjREҧQJJKLNӃWTXҧÿR

R1 a

R2 R3

R4

R5 b

c

d e f

g

h i

I1

(40)

%͡P{Q&XQJ&̭SĈL͏Q Trang 43 7. /jPOҥLFiFWKtQJKLӋPWӯSKҫQÿӃQQKѭQJYӟLQKӳQJJLiWUӏNKiFFӫDÿLӋQiS QJXӗQNӃWTXҧFǊQJJKLYjREҧQJWѭѫQJWӵWKӵFKLӋQtWQKҩWOjJLiWUӏQJXӗQÿLӋQNKiF nhau)

8. ĈR [iF ÿӏQK OҥL FiF JLi WUӏ ÿLӋQ WUӣ *LҧL PҥFK EҵQJ ÿӏQK OXұW 2KP ÿӇ NLӇP FKӭQJNӃWTXҧWKtQJKLӋP&KRQKұQ[pWYӅVӵNKiFELӋWQӃXFyJLӳDOêWKX\ӃWYjWKӵF QJKLӋP

%ҧQJJKLQKұQNӃWTXҧÿR

UCC I I1 I2 UR1 UR2,3 UR4 UR5 R1=

UR2 UR3

R2=

R3=

R4=

(41)

http://www.ebook.edu.vn &ặ8+,9ơ%ơ,73 &ặ8+,75&1*+,0

&kXKL\rXFXWUOLQKDQK

ĈӑFNӻFiFFkXKӓLFKӑQYjW{ÿHQêWUҧOӡLÿ~QJQKҩWYjR {WKtFKKӧSӣFӝWWѭѫQJ ӭQJ0ӛLFkXFKӍFyPӝWêÿXQJ

3.1. 'zQJÿLӋQ[RD\FKLӅXWKѭӡQJÿѭӧFÿREҵQJ a Ampe Kìm;

b VOM;

c Oátmét Vônmét; d Ampemét Vônmét

#ð #ð #ð #ð

3.2 KhiÿRGzQJÿLӋQKRһFÿLӋQiS*yFTXD\FӫDNLPFjQJOӟQ WKuNӃWOXұQ

a.7UӏVӕFjQJQKӓ b.7UӏVӕUҩWQKӓ c.7UӏVӕFjQJOӟQ d.7XǤORҥL

#ð #ð #ð #ð

3.3 KLÿRGzQJÿLӋQKRһFÿLӋQiSEҵQJPi\ÿRFKӍWKӏNLP7Uӏ VӕSKҧLÿѭӧFÿӑFWUӏWӯ

a 3KҧLTXDWUiL b 7UiLTXDSKҧL c *LӳDUDELrQ

#ð #ð #ð #ð

3.4 KLÿRÿLӋQiSĈӇSKpSÿRÿѭӧFFKtQK[iFÿLӋQWUӣFѫFҩX

ÿRVRYӟLÿLӋQWUӣWҧLSKҧL D5ҩWQKӓ

E%ҵQJQKDX F5ҩWOӟQ G/ӟQKѫQ

#ð #ð #ð #ð

(42)

%͡P{Q&XQJ&̭SĈL͏Q Trang 45 a Oátmét pha;

b OátPpWSKDSKҫQWӱ

c Vônmét;

G2iWPpWSKDSKҫQWӱ

3.6 &{QJVXҩWPҥQJSKDGk\ÿѭӧFÿRWUӵFWLӃSEҵQJ a Oátmét pha;

E2iWPpWSKDSKҫQWӱ F2iWPpWSKDSKҫQWӱ d Ampemét

#ð #ð #ð #ð

3.7 &{QJVXҩWPҥFKÿLӋQSKDGk\ÿѭӧFÿRJLiQWLӃSEҵQJ a Oátmét pha;

b Oátmét pha; c Oátmét pha; d Ampemét

#ð #ð #ð #ð

3.8 CôngVXҩWPҥFKÿLӋQSKDGk\ÿѭӧFÿRJLiQWLӃSEҵQJ a Oátmét pha;

b Oátmét pha; c Oátmét pha; d Ampemét

#ð #ð #ð #ð

3.9 'QJ2iWPpWSKDÿӇ ÿRF{QJVXҩWPҥQJSKDNKL a.0ҥQJSKDNK{QJFyGk\WUXQJWtQK

b.0ҥQJ SKD Fy Gk\ WUXQJ WtQK Yj SKө WҧL NK{QJ ÿӕL [ӭQJ

c.0ҥQJSKDFySKөWҧLNK{QJÿӕL[ӭQJ d.0ҥQJSKDWUXQJWKӃWUӣOrQ

#ð #ð #ð #ð

3.10 'QJ2iWPpWSKDÿӇÿRF{QJVXҩWPҥQJSKD khi: a.0ҥQJSKDNK{QJFyGk\WUXQJWtQK

(43)

c.0ҥQJSKDFySKөWҧLNK{QJÿӕL[ӭQJ d.0ҥQJSKDWUXQJWKӃWUӣOrQ

3.11 'QJ2iWPpWSKDÿӇÿRF{QJVXҩWSKDNKL a.0ҥQJSKDNK{QJFyGky trung tính;

c.0ҥQJSKDFyGk\WUXQJWtQKYjSKөWҧLÿӕL[ӭQJ d.0ҥQJSKDWUXQJWKӃWUӣOrQ

#ð #ð #ð #ð

3.12 &{QJVXҩWPҥQJÿLӋQPӝWFKLӅXÿѭӧFÿRJLiQWLӃSEҵQJ a Oátmét DC

b Vônmét Ampemét DC; c Oátmét pha;

d.&{QJWѫÿLӋQ

#ð #ð #ð #ð

3.13 &{QJVXҩWPҥQJÿLӋQPӝWFKLӅXÿѭӧFÿRWUӵFWLӃSEҵQJ a Oátmét DC

b Vônmét Ampemét DC; c Oátmét pha;

d.'&&{QJWѫÿLӋQ

#ð #ð #ð #ð

3.14 &XӝQGk\GzQJÿLӋQWURQJ2iWPpWSKDÿѭӧFPҳF a.1ӕLWLӃSYӟLWҧL

b SoQJVRQJYӟLWҧL c.6RQJVRQJYӟLQJXӗQ d.1ӕLTXDWөE

#ð #ð #ð #ð

3.15 &XӝQGk\ÿLӋQiSWURQJ2iWPpWPӝWSKDÿѭӧFPҳF a 1ӕLWLӃSYӟLWҧL

b 6RQJVRQJYӟLWҧL c 6RQJVRQJYӟLQJXӗQ d 1ӕLTXDWөE

#ð #ð #ð #ð

(44)

%͡P{Q&XQJ&̭SĈL͏Q Trang 47 a.&{QJVXҩW WiFGөQJ

b.&{QJVXҩWSKҧQNKiQJ c.&{QJVXҩWELӇXNLӃQ d.'XQJOѭӧQJFӫDWөE

3.17 &{QJWѫÿLӋQSKDGQJÿӇÿR

D&{QJVXҩWWLrXWKөFӫDKӝJLDÿuQK EĈLӋQQăQJWLrXWKөFӫDKӝJLDÿuQK F'zQJÿLӋQWLrXWKөFӫDKӝJLDÿuQK GĈLӋQQăQJWLrXWKөPҥQJ'&

#ð #ð #ð #ð

3.18 &XӝQ Gk\ GzQJ ÿLӋQ Yj FXӝQ Gk\ ÿLӋQ iS WURQJ F{QJ Wѫ SKDFyÿһFÿLӇP

a.&XӝQÿLӋQiSQKLӅXYzQJGk\QKӓ&XӝQGzQJÿLӋQtW vòng, dây to;

b.&XӝQ ÿLӋQ iS tW YzQJ Gk\ WR &XӝQ GzQJ ÿLӋQ QKLӅX YzQJGk\QKӓ

c.&XӝQ ÿLӋQ iS QKLӅX YzQJ Gk\ WR &XӝQ GzQJ ÿLӋQ tW YzQJGk\QKӓ

d.&XӝQÿLӋQiStWYzQJGk\QKӓ&XӝQGzQJÿLӋQQKLӅX vòng, dây to

#ð #ð #ð #ð

3.19 KLF{QJWѫÿLӋQNK{QJFyQDPFKkPYƭQKFӱXWKuKRҥWÿӝQJ

FӫDGƭDQK{PFyÿһFÿLӇP a.4XD\FKұPKѫQ b.4XD\QKDQKKѫQ c Không quay;

d.4XD\WKHRWҫQVӕQJXӗQ

#ð #ð #ð #ð

3.20 0ӝWF{QJWѫÿLӋQFyVӕYzQJTXD\FKRPӕL.:KOj.KL KLӋX FKӍQK QӃX GQJ EyQJ ÿqQ : ӣ ÿ~QJ ÿLӋQ iS ÿӏQK PӭFWKuWKӡLJLDQFKӍQKÿӏQKFKRPӝWYzQJTXD\Oj

a 30 giây; b 45 giây; c 60 giây;

(45)

d 75 giây

3.21 0XӕQNLӇPWUDWӕFÿӝTXD\³QKDQK´KD\³FKұP´FӫDF{QJWѫ pha 1JRjLF{QJVXҩWWҧLWDFzQSKҧLFăQFӭYjR

D+ҵQJVӕPi\ÿӃPFӫDF{QJWѫ EĈLӋQiSÿӏQKPӭFFӫDF{QJWѫ F'zQJÿLӋQWҧLTXDF{QJWѫ G7ҫQVӕÿLӋQiSQJXӗQ

#ð #ð #ð #ð

3.22 #ð #ð #ð #ð

3.23 0XӕQ ÿR GzQJ ÿLӋQ FKtQK [iF WKu ÿLӋQ WUӣ QӝL FӫD $PSHPpWNӃVRYӟLÿLӋQWUӣSKөWҧLSKҧL

a 1KӓKѫQQKLӅXOҫQ b /ӟQKѫQQKLӅXOҫQ c %ҵQJQKDX

d .K{QJVRViQKÿѭӧF

#ð #ð #ð #ð

3.24 0i\ELӃQGzQJÿLӋQ%,FyF{QJGөQg:

a.%LӃQ GzQJ ÿLӋQ QKӓ WKjQK GzQJ ÿLӋQ OӟQ SK KӧS YӟL F{QJVXҩWWҧL

b.%LӃQ GzQJ ÿLӋQ OӟQ WKjQK GzQJ ÿLӋQ QKӓ SK KӧS YӟL GөQJFөÿRWLrXFKXҭQ

c.%LӃQÿLӋQiSQKӓWKjQKÿLӋQiSOӟQSKKӧSYӟLÿLӋQiS FӫDWKLӃWEӏ

#ð #ð #ð #ð

Cho biӃt chӍsӕAmpemét Vônmét mҥFKÿLӋn hình vӁ

A A

B C

V

(46)

%͡P{Q&XQJ&̭SĈL͏Q Trang 49 d.%LӃQÿLӋQiSOӟQWKjQKÿLӋQiSQKӓSKKӧSYӟLGөQJFө

ÿRWLrXFKXҭQ

3.25 0i\ELӃQGzQJÿLӋQVӱGөQJWURQJF{QJQJKLӋSOjORҥL: a.%LӃQÿәLGzQJÿLӋQQKӓWKjQKGzQJÿLӋQOӟQ b.%LӃQÿәLGzQJÿLӋQOӟQWKjQKGzQJÿLӋQQKӓ c.&iFKO\GzQJÿLӋQFҫQÿRYӟLFѫFҩXÿR d.%LӃQÿәLF{QJVXҩWSKҧQNKiQg

(47)

http://www.ebook.edu.vn &+ѬѪ1*,V

Ĉ2&È&7+Ð1*6Ӕ&Ӫ$0Ҥ&+Ĉ,ӊ1

*LӟLWKLӋX

0XӕQOjPYLӋFYӟLPҥFKÿLӋQPӝWFiFKDQWRjQYjFyKLӋXTXҧWKuNKLWUӵFWLӃSOjP YLӋFYӟLPҥFKÿLӋQQJѭӡLF{QJQKkQFҫQSKҧLQҳPU}FiFWK{QJVӕFӫDPҥFK0XӕQYұ\ QJѭӡLF{QJQKkQSKҧL VӱGөQJWKjQKWKҥRFiFGөQJFөÿRELӃWFiFSKѭѫQJSKiSÿRYjFiF VѫÿӗÿӇÿRFiFWK{QJVӕFӫDPҥFKÿLӋQWURQJPӑLWUѭӡQJKӧSNӇFҧNKLNK{QJFyFiF WKLӃWEӏÿRSKKӧSYӟLFiFÿҥLOѭӧQJFҫQÿR

4.1. ĈRÿLӋQWUӣ5.

4.1.1ĈRÿLӋQWUӣJLiQWLӃS

1JX\rQWҳF%LӃWÿѭӧFGzQJÿLӋQTXDÿLӋQWUӣFҫQÿR5XYjÿLӋQiSJLiQJWUrQQyWKu

WKHRÿӏQKOXұW{PVӁ[iFÿӏQKÿѭӧFÿLӋQWUӣÿy

I U Rx

D3KѭѫQJSKiSGQJY{QPpWYj$PSHPpW

-ĈRÿLӋQWUӣQKӓ+uQK4.1)

Ta có: I = Ix+ Iv

v x

x v v

x v

x R r

R r U r R U r U R

U

áá Ã ăă

â Đ

1

V

IX

RX

IV

RV

A

U

I

(48)

http://www.ebook.edu.vn v x x v r R U I Oҩ\ÿLӋQiS8FKLDFKRYӃWDFy x v v x v x v x R r r R r R r R I U

&KLDWӱYjPүXFӫDYӃSKҧ,FKRUvta có:

v x x r R R I U 1

RxFjQJQKӓVRYӟLUv 1 | v x r

R Nên Rx

I U

| 1JKƭDOjVDLVӕFjQJQKӓ

.ӃWOXұQ6ѫÿӗ$PSHPpWYj9{Q PpWWKѭӡQJÿѭӧFGQJÿӇÿR FiFÿLӋQWUӣ5x

QKӓKѫQQKLӅXOҫQtWQKҩWOҫQVRYӟLÿLӋQWUӣWURQJUv FӫD9{QPpW

-ĈR ÿLӋQWUӣWUXQJEuQKYjWѭѫQJÿӕLOӟQ+uQK

3KkQWtFKWѭѫQJWӵQKѭWUrQWDFy A x r R I U

1ӃX5xFjQJOӟQWKuҧQKKѭӣQJFӫDUAFjQJNK{QJÿiQJNӇ

.ӃWOXұQ6ѫÿӗ9{QPpWYj$PSHPpWWKѭӡQJÿѭӧFGQJÿӇÿR FiFÿLӋQWUӣ5xOӟQ

KѫQQKLӅXOҫQtWQKҩWOҫQVRYӟLÿLӋQWUӣWURQJUA FӫD$PSHPpW

EĈREҵQJFҫXÿѫQ:KHDVWRQH+uQK

V RX

A

x

U

I RA

(49)

ĈLӅXFKӍQKFiFELӃQWUӣ52, R3, R3 ÿӇNLPÿLӋQNӃFKӍNK{QJ7DQyLFҫXÿmFkQ

EҵQJ

UA= UB

Hay UAB NK{QJFyGzQJÿLӋQTXDQKiQK$%

UDA= UDB I2 R2= I1.R4 (4.1)

UAC = UBC I2RX= I1.R3 (4.2)

&KLDFKRWDÿѭӧF

3

R R R

R

X

3

R R R Rx

k R R

2 WKѭӡQJÿѭӧFÿLӅXFKӍQKWKHRFiFWӹOӋELӃWWUѭӟFNKLÿRFKӍFҫQÿLӅXFKӍQK R37X\QKLrQNKLÿmÿLӅXFKӍQK53 UӗLPjFҫXÿRYүQNK{QJFkQEҵQJWKuWDSKҧLFKӑQ

OҥLWӹVӕ

4 R

R UӗLÿLӅXFKӍQK5

3FKRFҫXFkQEҵQJ

3KѭѫQJSKiSQj\ÿRFKtQK[iFQKѭQJFҩXWҥRSKӭFWҥSJLiWKjQKÿҳW ĈRÿLӋQWUӣWUӵFWLӃS

7KLӃWEӏGQJÿӇÿRÿLӋQWUӣWUӵFWLӃSJӑLOj{PPpW êKLӋX

DĈREҵQJ{PPpW

-ĈҩXQӕLWLӃS+uQK

$%&'/jÿӍnh cӫa cҫXÿR

AD, DB, BC, CA: nhánh cӫa cҫXÿR

Rx/jÿLӋn trӣcҫQÿR

R2, R3, R3: biӃn trӣmүu

R4 D

Unguӗn

K B

I2

R3

R2 A

I1 G RX

Hình 4.3: Cҫu Wheastone

(50)

.KLÿRGzQJÿLӋQ TXDFѫFҩXÿRVӁOj

m X

P R R

R U I

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

Định dạng
Số trang	65
Dung lượng	747,85 KB