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Gio trnh My đin
Trang 23

§2.13 QU TRNH M MY ĐNG CƠ ĐIN KHÔNG ĐNG B:



( 





 = 0) 














h. (n = 0  n

)














 , 





























 . 








mm

.
M

: 


M


= M

- M
C
M
C
: 


M

: 




M

= j.
dt
d

> 0
J =
g
GD
4
2
: 




 G : 

.
D : 




g = 10m/s
2


.
 : 



.
 



: s = 1
ñm
2
21
2
21

1
mm
I)74(
)'xx()'rr(
U
I 



 
 
2
21
2
211
2
2
11
mm
)'xx('rrf2
'r.U.p.m
M




































. 












.
 



:
.



















> 0 .




.





















 .














 



.
§2.14 CC PHƢƠNG PHP M MY:
2.14.1 Đng cơ rotor lng sc:
Gio trnh My đin
Trang 24
a) Phương pha
́
p mơ
̉
ma
́

y trư
̣
c tiê
́
p:
























.













 , 



 








. 






















.
b) Khơ
̉
i đô
̣
ng bă
̀
ng ca
́
ch gia
̉
m điê
̣

n a
́
p (khơ
̉
i đô
̣
ng gia
́
n tiê
́
p qua điê
̣
n trơ
̉
, cuô
̣
n
khng, biê
́
n a
́
p, đô
̉
i nô
́
i sao – tam gia
́
c ) :





















 . 


mm

U
2






mm
. 




mm

2
.
(a) Dng cun khng nối vơ
́
i ma
̣
ch điê
̣
n stator:




: 

1, 












 . 






 2, 







 ,  ,
M
mm

2
.










L1
L2
M
3 
L3
CB
L1
L2
L3
M
3 
K
RN
RN
K
D
M
K
U
V
W
A
B
C
CD

1
M
3 
CD
2
CK

K
1
A
B
C
K
2
M
3 
K
3
BA
Gio trnh My đin
Trang 25






(b) Dng bin p t ngu:

2

, M
mm

2
.










:
 


1
.
 


2















 . 








 (70-
80)%U

.
 





, 
1




3


.
(c) Dng phương php đi ni Y -

:


















 , 



, 











.
 Z
f
: 



.
U
l
: 










.




: U
l
=
3
U
fY
, I
fY
= I
dY

I
dY
= I
fY
=
f
l
Z
U
3


K



 : U
l
= U
fY
, I
d
=
3
I
f
=
3
f
l
Z
U




3
1
33


l

f
f
l
d
dY
U
Z
.
Z
U
I
I
=> I
dY
=
3
d
I
.


: 3 , 
3
, M
mm
(
3
)
2
= 3 .











.





A
B
C
CD
1
A

B

C

Gio trnh My đin
Trang 26











2.14.2 Đng cơ rotor dây quâ
́
n:
2
21
2
p21

mm
)'XX()'R'rr(
U
I



M
mm
=
])'XX()'R'rr[(f2
)'R'r(PUm
2

21
2
P211
P2
2
11




mm

mm
. 

















.




 
.









§2.15. ĐIÊ
̀
U CHI
̉
NH TÔ
́
C ĐÔ
̣
ĐÔ
̣
NG CƠ KHÔNG ĐÔ
̀
NG BÔ
̣

3 PHA:


















 :
A
B
M
3 
R
p
C
Gio trnh My đin
Trang 27
n = (1  s) n

1
= (1  s)
P
f
1
60













1 trong 3 :
s, f, p.
2.15.1 Thay đô
̉
i sô
́

̣
c tƣ
̀
:

 











 ( 



 ) 




.











2 

 (



 )  2 : 1.

 . 










trên rotor. 












 . 



















 








.

 :
 : M = const.
 : P = const.
 , , 





. M,P  const.
a) M = const:
 

: (YY)

4
, T
5
, T
6
.

1
- T
2
- T
3

.
  

: ()

1
, T
2
, T
3
.

T
1
T
4
T
6
T
5
T
3
T
2
A
2
X
2
X
1

A
1
Y
2
B
2
Y
1
B
1
C
2
Z
2
C
1
Z
1
Gio trnh My đin
Trang 28


:

2 p
1
= 4
n
11
=

1
60
p
f
= 1500 v/ph.






2 p
2
= 8
n
21
=
2
60
p
f
= 750 v/ph.
Chư
́
ng minh :
:
U
d
: 








I : 








th
:







 h
(2p
2
)

c

: 








(2p
1
)
cos
th
: 




.
cos
c
: 




.

 






: :
 





: U
pha
=
3
d
U

 (



2 ) 2I















:
(1)
(2)
(3)
(4)
N
S
N
S
A
1
A
2
X
1
X
2
T
4
S
S
S

S
A
1
A
2
X
1
X
2
T
1
N
N
N
N
T
5
T
6
T
2
T
1
T
3
U
pha
U
d
I

I
2I
L
1
L
3
L
2
Gio trnh My đin
Trang 29
ccdcc
d
c
cos.IUcos.).I.(
U
P

322
3
3 











 Kh





:
 







: U
pha
= U
d

 : I
P
th
= 3.U
d
.I.
th
.cos
th


:









cc
thth
ccd
ththd
c
th
cos.
cos.
,
cosIU
cosIU
P
P




8660
32
3











cc
thth
c
th
cos.
cos.
,
P
P


8660


  M
c
.
M
th
 






.


:
c
c
c
n
P
M

2



th
th
th
n
P
M

2





: n
c
= 2.n
th



:
c
th
th
c
c
th
c
th
P
P
n
n
.
P
P
M
M
2












cc
thth
c
th
cos.
cos.
M
M


3







:

70,

cos.
cos.
cc
thth




60,
P
P
c
th

&
21,
M
M
c
th


: 

,  

:
  0,6 







.
n
01
M = const

M

n
02
n

M
c
0

Gio trnh My đin
Trang 30
 
th


1,2 
c
(

)

b) Trươ
̀
ng hơ
̣
p P = const:
 

: .

4
, T
5
, T
6
 

: YY:

1
, T
2
, T
3


4
 T
5
 T
6

.











 :
U
pha
= U
d
, .








:
P
c
= 3 U

d
I cos
c

c

 :
3
d
ph
U
U 
; 2I
P
th
= 3








3
d
U
(2I)cos
th


th

= 2
3
U
d
Icos
th

th
8070151 ,,.,
cosIU3
cosIU32
P
P
ccd
ththd
c
th




T
1
T
6
T
2
T

5
T
4
T
3
C
1
Z
1
Z
2
C
2
A
1
X
1
X
2
A
2
Y
2
B
2
B
1
Y
1
T

1
T
6
T
2
T
5
T
4
T
3
I

U
d
= U
p
n
01
M

n
02
n


0

YY
M

c
I

I

2I

U
d
Gio trnh My đin
Trang 31


:
612802 ,.,
P
P
M
M
c
th
c
th




: P
th
= 0,8 P

c
 

.
M
th
= 1,6 M
c


















c) Trươ
̀
ng hơ
̣

p P, M

const.
 

: YY.
: T
4
, T
5
, T
6

: T
1
 T
2
T
3
.
  

: Y
: T
1
-T
2
-T
3.








X
1
A
2
S
N
S
A
1
X
2
T
4
N
N
N
N
N
A
1
A
2
X
1

X
2
T
1
S
S
S
T
6
S
A
1
B
1
Z
2
T
3
C
1
X
2
T
1
T
4
T
6
T
5

T
2
A
2
X
1
Y
2
B
2
Y
1
C
2
Z
1
n
01
M

n
02
n

Y
0

YY
M
C

Gio trnh My đin
Trang 32
3
d
p
U
U 
; 
P
th
= 3








3
d
U
(2I)cos
th

th
= 2
3
U
d

Icos
th

th










P
c
= 3








3
d
U
(2I) cos
c


c
= 2
3
cos
c

c
=>
3507050
32
3
,,.,
cos
cos
P
P
cc
thth
c
th




=>
7035022 ,,.
P
P
M

M
c
th
c
th




: P
th
= 0,35 P
c

M
th
= 0,7 M
c


 V sơ đ dây qun đng cơ 3 pha hai tô
́
c đô
̣

: - 





- 

2p
1
(

); 2p
2
(

): 2p
1
= ½ 2p
2

: - 

:

2
2p
Z
y 

- 

/pha/:

)p(
Z

q
1
23


A
1
B
1
Z
2
T
3
C
1
X
2
T
1
T
4
T
6
T
5
T
2
A
2
X

1
Y
2
B
2
Y
1
C
2
Z
1
I













Gio trnh My đin
Trang 33
2.15.2 Thay đô
̉
i tâ

̀
n sô
́
:
n = (1  s) n
1
= (1 s)
p
f60

 
1





 : .
 

:
 












& 

.
  











 => 


 

=> 
f
U
= .


: M = C. .I.cos = const <=>  = const.

 



:












 u 50Hz (1 pha hay 3 pha) 



, 

, 









2: 





3 

:
 







 (CSI).  , 






.
 

 (PAM). 


 , 
.



(PWM). Êm ,

.
2.15.3 Phƣơng pha
́
p thay đ điê
̣
n a
́
p:











2
. 
M










 , 





a
 s
b
 s
c
.




















 , 










& 





, 





M
U

U
1
U
2
1

c

b

a

s
m
s
c
s
b
s
a
s

M

0


U

> U
1
> U
2

Gio trnh My đin
Trang 34




.

p ( ) 


.
0 < n < n


n

< n < n
max

2.15.4 Phƣơng pha
́

p thay đô
̉
i điê
̣
n trơ
̉
phu
̣
trên ma
̣
ch rotor:
's
'r'r
s
'r
p


2
2
 n' = n
1
(1 s')






 , R

p
 
 



.
















 , tuy


,  , 













trong 


: P

= m
1
I'
2
2
s
'r
2
=>

ñtñt
M
'r'Im
P
'r'Im
s

2
2
212
2
21


×