BÀI SEMINAR đề tài các bài tập về máy biến thế

ĐẠI HỌC SƯ PHẠM TP HCM


BÀI SEMINAR
Đề tài:
 !"#$%&
'$()**+,
-$.
/0/
1
21341343516
 )%789:$
;%<8= 
LỜI NÓI ĐẦU 2
I. MÁY BIẾN THẾ 3
1. Khái niệm 3
2. Vai trò của máy biến áp 3
3. Các đại lượng định mức của máy biến áp 4
4. Cấu tạo và nguyên tắc hoạt động 4
>?1?@(& A!$????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????>
>?1?1@(& A!B!??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????>
>?1?3@(& A!!!????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????.
4.2 Nguyên lý làm việc của máy biến áp 6
>?3?18()"# &*B8A!B!????????????????????????????????????????????????????????????????????????????????????????????????????C
>?3?3?8()"#"+A!!!?????????????????????????????????????????????????????????????????????????????????????????????????????????D
5. Khảo sát máy biến thế 7
6. Sự truyền tải điện năng 8
II. CÁC DẠNG BÀI TẬP CỦA MÁY BIẾN THẾ 9
1. Dạng 1 : Máy biến áp không tải 9
2. Dạng 2 : Máy biến áp có tải 19

3. Dạng 3 : Công suất, hiệu suất, hệ số của máy biến áp 25
LỜI NÓI ĐẦU
E8!*(;F82G" &8!*H*&*%IJ8;K"#,
LM8"NOP"%I8Q8%"@"%I8?*R-*%IJ8;K 8E*NOB
%+!2,A!E8!*HS;ST(!BT(;==U28)
K("G(98!LM?V-J8,SOSG=*RS +
BG"#L !,?
B    W(    "#  *H  *%I  O8    O7  @   X      "#  Y; "
Z[; \OL 2LO!]^;_-(O`a" bc1dd>*H"!*MG" &?
e89/8A!-*H8E" 8%fL+OK"W2@*K&OW!*M
3
A!+(*+g?-"OW;!?B8<*%IK89/8;@
;B8;H; 8-?RR(;h<@(& Q8%K89/8A!-B
iG(Oj<2-i;=;h9&8A!-?
(-P8j8%8jjL'8;LkJ8(O-; 8T(;=
="+(Q8%LKU&A!-2 8*%I(#L*-8
8-A!l'8 &*RO[!;*%I S <?
I. MÁY BIẾN THẾ.
1. Khái niệm.
8!9 +Om9/8*+c8;R;@;B8;H)-J8" &
)L!($an1!2an6!g%8E8*(9W!;)1
8()"#2*-"8()"#SK8*+o?
"9/8/*+op*%I"+9W!;)8()"#SK8
*+o29q8*R*MB+P89U8*+i !(o*++
P89U8*+i !(*+L%8"('-lOPL'8*M?
2. Vai trò của máy biến áp.
R;(S*+c8*i!S9q8*%f89GS*+-*+!
*R8SM@*+c8;)*%f89G?Rc8*+")! !S9q8
?
&B)(/*+9 L'8R;WOm9/8*+! 2="#9 ! 

 *B8<"+*<8S??
6
*%IOm9/8;B8;H; 8Lr(2"+/
;(SGPc8"%I8?
3. Các đại lượng định mức của máy biến áp.
Điện áp định mức: ,s
1*
"*+T(*t 9GT(@O<@s
3*
"
*+T(*t 9GT(@K@2L9GT(@K@X&*+*u
 9GT(@O<@"*tK?<t*+8;)%f8"v uv?
Dòng điện định mức$,w
1*
"9U8*+O<@*tKw
3*
"9U8*+
K@*tK?]U8*+*tK"9U8*+*HT(*t x9GT(@
A!2K87'8O(@*tK*+*tK?<t9U8*+
8;)%f8"n?
Công suất định mức: '8O(@*tKA!"'8O(@R(
L*tK?#+("
*
?<t"vn2vn?
+ P7B-$

*
ys
3*
?w

3*
ys
1*
?w
1*
zP7!!-$

*
y
6
s
3*
?w
3*
y
6
s
1*
?w
1*
Quy ước:
z  an  B  !  *+    *t  K  "  *+    !  
9U8*+*tK"9U8*+!?
zan!!*+*tK"*+9G9U8*+*tK"
9U8*+9G?
4. Cấu tạo và nguyên tắc hoạt động.
4.1. Cấu tạo của máy biến áp:
4.1.1 Cấu tạo của máy biến áp một pha.
B!-!BV""h^9GT(@?
>

z0h^*%I& oJ8"+(9:oP{%^"g|9q8*R9:o
'8?0h^8N!BV";/8'8
• ;/"<*R*u9GT(@?
• '8"lL^LV&o8J!;/?
J!;/8'8& &oL^LV?
z]GT(@%f8*%I"F89G*N89:*+P)8 9G9:-,
*+?]GT(@8N(U89G"N8 ;/"h^?
J!U89G28J!9GT(@-*+7!(9GT(@
*+7"h^?
4.1.2 Cấu tạo của máy biến áp ba pha.
NBV""h^29GT(@k?
0h^!!8N!;/?
]GT(@$
z]GT(@O<@L#+(F8J !
• !nLV+("n}2LV+(*l(*l("n2a2
• !aLV+("a}2LV+(*l((P"}2~2Z
• !LV+("}?
z]GT(@K@LV+(F8Q%f8?
• !!LV+("!i2LV+(*l(*l("!22
• !LV+("i2LV+(*l((P"i22`?
• !LV+("i?
]GT(@O<@K@-RPO!  uP!8
.

i
! 
 `
\
1
\

3
~
Z

}
n a
PO! Υ*+O•8S*
6
"l28SV*+?
P!8∆9U8*+O•8S*
6
"l28S9+9G?
v7c8%f8*%IPO! !8Υ4∆?
v78S%f8*%IPO! !8∆4Υ?
4.2 Nguyên lý làm việc của máy biến áp.
4.2.1 Nguyên lý hoạt động của máy biến áp một pha.
}^%=•$

!P8(N*+-*+(
1
 (B9GO<@=O•-9U8*+
O<@
1? 
]U8*+
1 
O;!o'8); 8"h^9 &o
L^LV)o'89(Ro(BO<@O!8(BK@?
[ *t"(SK8*+o!-O(@*+*B8"$
ε


ε
1
y
1
dt
d
Φ


ε
3
y
3
dt
d
Φ
C
]GT(@K@P7S?]%7*B8A!O(@*+*B8[
3
SK8
O•O;!9U8*+
3
*%!;!S7*+(
3
?0E*-o'89 S!
9U8*+O<@
1
K@
3
O;!?

SOm*+i !(*u "BOP=O)o'8Q8
)[ =O$ΦyΦ
!i
Oω€ωy3π•?
!-$
ε
1
y
1
dt
td
ω
O
!i
Φ

yω
1
Φ
!i
 Oω
y3π•
1
Φ
!i
O{ωπ43|y
y>2>>•
1
Φ
!i

3
O{ωπ43|y
3
‚
1
O{ωπ43|
ε
3
y
3
dt
td
ω
O
!i
Φ

yω
3
Φ
!i
 Oωy3π•
3
Φ
!i
O{ωπ43|y
y>2>>•
3
Φ
!i

3
O{ωπ43|y
3
‚
3
O{ωπ43|
; 8*-$
‚
1
y
3
π•
1
Φ
!i
y>?>>•
1
Φ
!i
‚
3
y
3
π•
3
Φ
!i
y>?>>•
3
Φ

!i
4.2.2. Nguyên lý làm việc của máy biến áp ba pha.
8()"#"+A!!!%<8W%8()"#"+A!
B!?
,
1
"OPU89G!B!O<@
3
"OPU89GB!K@
ƒOP*+!8J!O<@K@O•"
1
1
3 3
p
p
U
N
k
U N
= =
ƒOP!!L'8„/(B OPU89GU/
(B *@(P!!"PO! Υ!!8∆?
5. Khảo sát máy biến thế.
,
12

3
"OPU8A!(BO<@K@?
,s
1

2s
3
"+(*+3*l((BO<@K@?
,w
1
2w
3
"%f8*B+(9/8A!9U8*+3*l((BO<@K@?
D
; 8L S8f8!…'q8ko'8)8G;!; 8xU8
9GA!S!(BO(@*+*B8F8$
5
t
φ
ε
∆
= −
∆

(@*+*B8;)B(BO<@"$
1 1 5
?N
ε ε
=
(@*+*B8;)(BK@$
1 3 5
 ?
ε ε
=


y†„OP*+3*l((BK@F8„OPU89GA!3(B%<8K8
1 3
3 1


ε
ε
=

„OP
1
3
ε
ε
L'8*M[ f8!)!-R!F88;t+(9/8!
*%I
1 3
3 1


ε
ε
=
(1)
+;X(lA!(BO<@;@k)s
1
2y‚
1
L&K@X)s
3

y‚
3

(2)
o(1)(2)!*%I
3 3
1 1


U
U
=
{‡|
ˆ(
3
†
1
y†s
3
†s
1
$8,"c8?
ˆ(
3
‰
1
y†s
3
‰s
1

$8,"&?
v=! VX;@k2 %'8O(@X3*l((BK@O<@
%!(?
1 3
1 3 1 1 3 3
3 1
U I
P P U I U I
U I
= ⇔ = ⇒ =
{‡‡|
o{‡|{‡‡|!-
1 1 3
3 3 1


U I
U I
= =

6. Sự truyền tải điện năng.
+c8OSi(@*%I;(S*<)(/;)*%f89G9:98
;cL?'8O(@l;(S$ys?w? O
ϕ
(1)
d
; 8*-$"'8O(@l;(*2s"*+&<;(*2w"%f8*B
9U8*+;)9G9:;(S2 OŠ"+OP'8O(@?
o{1|y†
s? O 

P
ϕ
yw
[ +(K8+‹(0[i<'8O(@! V…9%79&8k!+ LV
T(R!-$
3
3
3
?
?
s? O {s? O |
P P R
P R
ϕ ϕ
 
∆ = =
 ÷
 

7"*+;X*%f89G
v'8O(Gk!+;)*%f89GL;(S*+c8*i!"
3
3
3
?
?
s? O {s? O |
P P R
P R
ϕ ϕ

 
∆ = =
 ÷
 

RL*<Om9/8=/)(""O! *R8SS'8O(@k!+…
*Rl"7*+c8*%IOm9/8J(V?-!%<88S…?
ˆPhương án 1$Giảm R?
]
l
R
S
ρ
=
)*R8S=lSc89+A!9G9:?%<8
L'8LS9 PL^L?
• Phương án 2 : Tăng U.
aF8Om9/82c8*+s;%7L;(S*=
'8O(@k!+;)*%f89GO•*%I&?%<8LS
<=L'8PL^2%f8*%IOm9/8; 8W?
II. CÁC DẠNG BÀI TẬP CỦA MÁY BIẾN THẾ.
1. Dạng 1 : Máy biến áp không tải.
Câu 1?(BK@SB-d55U8?o'8; 8"h
)7lOP.5`8;to'8W*&T(!BU89GF8
32>Œ?VO(@*+*B8+(9/8(BK@?
n?335va?>.C2dv?>3C2.v]?1>5v
•
%789:$
!-'8KO(@*+*B8+(9/8"$
6

5 5
3 
3 ?.5?d55?32>?15
>3C2.
3 3 3
f
V
ε π φ
π
ε
−
= = = ≈ ⇒
,
Câu 2$B-(BO<@1555U89G*%Ij &8*+
i !(-*++(9/8"335v?*-*++(9/8X!*l((B
K@*RX">d>v?akT(!,! VA!?'U89GA!(B
K@"?
n?3.55a?1155?3555]?3355
%789:$
!-$
3 3
3
1 1 3
 335 1555
 3355
 >d> 
U
U
= ⇒ = ⇒ = ⇒
,]

Chú ý :(B(B9G *-{9(BO<@|-U89GT(@
8%I=o;%f8A!U89G8%I7o;%f8A!lU"&)-
-9/8Lm7o;%f8A!U89GU"&2K"(B9Gt@*
3U8?
1 1
3 3
 3

U n
U
−
=
Câu 3$B8%f*t(PBo+(*)s
1
y115v9G-
*+;X;@k27OPU8(BK87123U84v'?8%f*-(P*E8
  (BK@%8"&(P8%I(J8U8(PA!(BO<
@?m78(NK@* *%Is
3
y3C>vO 7(BO<@*E8
)(l(L2*+8(N"s
1
y115v2s
3
?y335v?PU89Gt(P
8%I"$
n35a11?15]33
%789:$
15
,OPU8(B9GA!an[ *E8)(l("

1

3
 !-
1
3
 115 1
 335 3
= =
y†
3
y3
1
{1|v7
1
y115i123y163U8
,"OPU89Gt(P8%I?*-!-

1 1
3 1
 3  3115 115
 3C> 3 3C>
n n
− −
= ⇒ =
{3|
 !
1
y163U8!=*%Iy11U8?
Chú ý: (BO<@t(P8%IU8=O(@*+*B8SK8

i(@+X(BO<@K@"@"%I"
ε
1
y{
1
|
ε
5
Ž
ε
5
y{
1
Ž3|
ε
5
7
ε
5
O(@*+*B8SK8i(@+X
xU89G?

ε
3
y
3
ε
5
] *-
1 1 1 1 1

3 3 3 3 3
 3  3 115
  3C>
n E U n
E U
ε
ε
− −
= = = ⇒ =
Câu 4$B"V%X8-(BO<@8N155U89G(BK
@8N1.5U89G?j!*l((BO<@ &8*+i !(-*+
+(9/8".v?(X(BO<@-15U89GtT(@8%I=*+
+(9/8X!*l((BK@L*RX"$
n?D2.55va?•26D.v?d2666v]?D2Dd5v
%789:$$
(BO<@i[%@*35U8$
1 1
3
3 3 3
 3 . 155 35
•26D.
 1.5
U n
U
U U
− −
= ⇒ = ⇒ =
{v|
⇒
,a

Câu 5$B7(BO<@8N1555U89Gj &8
*+i !(?(BK@8N.5U8?akT(!,! VX?
(BK@P7*+;X(l=9U89+&T(!(BK@"1{n|?
Hi*t9U8*+&T(!(BO<@?
n?525.na?525Cn?525Dn]?525dn
11
%789:$
v="V%X8(BK@P7)!9/8'8K$
1 1 3 3
1 3
3 3 1 1
 
525.
 
U I
I I A
U I
= = ⇒ = = ⇒

,n
Câu 6$B"#%X88NB(BO<@!(BK@?(B
O<@-
1
y1635U82*+s
1
y335v?(BK@K@-s
3
y15v2w
3
y

52.n€(BK@K3-
6
y3.U82w
6
y123n?%f8*B9U8*+T(!(BO<
@"$
A. 5256.n B. 525>.n C. 52536nD. 525 n
%789:$
]U8*+T(!(BO<@w
1
yw
13
zw
16

•

13 3
13
3 1
15 1
52.? { |
335 >>
I U
I A
I U
= ⇒ = =
•
16 6 6
16

6 1 1
3. . . 1
123? { |
1635 3C> 3C> >>
I U n
I A
I U n
= = = = ⇒ = =
⇒
w
1
yw
13
zw
16
y
3 1
525>.{ |
>> 33
A= =
Câu 7$B"V%X8-„OPU89GA!(BO<@K@"
3?(BK@P7S)(/-*+;X355
Ω
2(BO<@P7*+
i !(-8;t+(9/8355v?]U8*++(9/8T(!(BO<@"$
n523.na?52Cn?52.n]?52dn
%789:$$
v="V%X8(BK@P7)!9/8'8K$
13
3 3

3 1 3
1
1 1 3
3
3 3 1
1 3
1

155{ | 52.



523.{ |

U
U U V I A
r
U N I
U I
I I A

= = ⇒ = =


= = ⇒


= =




⇒
,n
Chú ý:*P7"V%X8(BK@-(*l(;!{•8&-
!*l(;!|*l(P7=9/8'8K$
3 3
1 1
6
3
1 1 3 3 6 6 3 6
6 6
1 1


2


sc tc
U
U
U
U
P P U I U I U I I I
U
R R
U

=



= = = + = =

′

=


(9/8'8K
1 1 3
3 3 1


U I
U I
= =
2
6 6
1
1 1 6


U
I
U I
= =
=9:*LT(SO!?
Câu 8$u !*l((BO<@A!B"V%X8{kT(!!
V|B*+i !(-8;t+(9/8L'8*M=*++(9/88J!
!*l((BK@*RX"155v?•(BK@2(8S7U89G(=*+
+(9/88J!!*l(*RXA!-"s2(c8)U89G=*+*-

"3s?(c8)6U89GX(BK@=*++(9/88J!!*l(
*RXA!(BF8$
n?155va?355v?335v]?115v
%789:$
!-$
3
1 1
3
1 1
3 3 3 3
3
1 1 3
1 1
3 3
1
1 1 1 1 1
155
3
3
6
6 ‘ ‘ 155
3? 3? 355
N
N U
N n
U
N U
N U N n N
n
N n U

N U N n
N U
N n NU U
U V
N U N U U

=



−

=


+
 
= ⇒ ⇒ = ⇒ =
 
+
−
 
=
 


+

= = ⇒ = ⇒ =



,a
16
Câu 9$u !*l((BO<@A!B"V%X8{kT(!!
V|B*+i !(-8;t+(9/8L'8*M=*++(9/88J!
!*l((BK@*RX"655v?(8S7Bl!M8OPU89GA!
(BK@=*++(9/88J!!*l(*RXA!-"$
n?155va?355v?335v]?115v
%789:$
3
3
3 3 3 3
1 1 1 1 1
3 3
3
3
‘
3
6
€ ?
6
‘ ‘
3 3
‘ 355
6 655 6
N
N
N U U N
N U U N N
U U

U V
U
−
= = =
⇒ = ⇒ = ⇒ =
,a
Câu 10: B-(PO<@1555U89G*%Ij &8
*+i !(-*++(9/8"335v?*-*++(9/8X!*l(
(BK@*RX">d>v?akT(!,! VA!?PU89GA!
(BK@"?
n?3.55a?1155?3555]?3355
%789:$
!-$
1 1
3
3 3 3
335 1555
3355
>d>
= ⇒ = ⇒ = ⇒
N U
N
N U N
,]
Câu 11{Pn3516): u !*l((BO<@A!
1
B
*+i !(-8;t+(9/8355v?P!*l((BO<@A!

3

 !*l((BK@A!
1
=*++(9/8X!*l((BK
@A!
3
*RXF8132.v?P!*l((BK@A!
3
7!*l((B
K@A!
1
=*++(9/8X!*l((BO<@A!
3
*RXF8.5v?
akT(!,! V?
1
-„OPU89GO<@OPU89GK@F8?
n?da?>?C]?1.
1>
%789:$
1$P!*l((BO<@A!
3
 !*l((BK@A!
1
=$
3 1
1 3
s s
=

3

3
s 132.v
=
? {1|
3$P!*l((BK@A!
3
7!*l((BK@A!
1
=$
3 1
‘
1 3
s s
=

3
‘
3
s .5v
=
? {3|
!-$
3 3
3 
3
‘
1 1
‘
3 3
s ?s

1
s ?s
=
 {6|
!{1|{3| {6|!*%I$
1
1
3
3
3
s
1 s .5?132. 3.v
.5?132.
= ⇒ = =
v$
1
1
1
1
3 3
s
 355
d
 s 3.
= = =
y†,n
Câu 12(Pn3511|$B,OT(@B79W*tOPU8
9GA!(BO<@8@3"lOPU89G(K@?] O<O(@)(BK
@t(BOPU89G?(Pi*tOPU89G(*R(P)
 (BK@ *A2,O*u !*l((BO<@B*+i !

(-8;t+(9/8L'8*M2;N9q8'Li*t„OP*+X(B
K@*RX(BO<@?0E*l(„OP*+"52>6?!(LT(@) 
(BK@3>U89G=„OP*+F852>.?akT(!,!V; 8
?R*%I*E8%9W*t2,O/ST(@
(BK@?
n?155U89G a?d>U89G?C5U89G ]?>5U89G
%789:$
[ *!-$
1 3
 3
=
uL
3 3 3
1 3 1
3 3 3
1 3 1
 i 3>  i 3> s
52>6
 3 s
 i  i s
52>.
 3 s
− − − −

= = =



− −


= = =


1.
⇒
iyC5U8
⇒
,
Câu 13(Pn3515|$u !*l((BO<@A!"V%X8
{kT(!! V|B*+i !(-8;t+(9/8L'8*M=*+
+(9/88J!!*l((BK@*RX"155v?•(BK@2(8S7
U89G=*++(9/88J!!*l(*RXA!-"s2(c8)U8
9G=*+*-"3s?(c8)6U89GX(BK@=*++(
9/8F8
n?115va?155v?335v]?355v
%789:$
!-
1 1
3
1 1
3
1 1
3
s 
155 
s 
s  
s 
3s  


=



=

−


=

+

y†
1 1
3
1 1
s 
155 
3 3  

=



− = +

y†
1 1
3

1
s 
155 
 6

=



=

}^
1 1 1 1
3
3 3 3
s   s
s 355v
s  6 3 3?155
= = = ⇒ =
+
y†,]
Câu 14?B,O(PB-OPU89G(BK@8@3
"lOPU89G(BO<@?*u !*l((BO<@*+i !(-
8;t+(9/8s=*++(9/8X!*l((BK@*RX"12•3s?
LR;!
’
@+; 8(BK@->5“U89GtT(@8%I(O 
7*!OPU89G; 8*-?akT(!,! V?M8OPU8
9G*H*%IT(@; 8"$
n?3555U8?a?6555U8??C555U8?]?1.55U8?

%789:$
,
1
"OPU89G(BO<@?*-OPU89G(BK@
3
y3
1
?
M8OPU89GA!"6
1
[ ;!!-$
U
U
•321
y
1
3
d5
N
N
−
y†12•3
1
y3
1
Žd5y†
1
y1555U8
y†
3

y3555U8
1C
!-y
1
z
3
y6555U8y†,a
Câu 15$u *l((B9GO<@A!B"V%X8B*+
i !(-8;t+(9/8L'8*M=*++(9/88J!!*l((BK
@*RXA!-"155v?(„c8U89GX(BO<@=*+
+(9/88J!!*l(*RXA!(BK@"s(„8SU89GX(B
9GO<@=*++(9/88J!!*l(*RXA!(BK@"3s?(„
c8)3U89GX(BO<@=*+@+(9/88J!!*l((BK@
*RX"$
n?.5va?C5v?155v]?135v
%789:$
3
1 1
3
1 1
3 3 1 1
3
1 1 1
1 1
1 1 1 1 1
3 3
155
3
3
6

3 . .
? ? ‘ C5
‘ 6 ‘ 6 155
N
N U
N
U
N n U
N U N n N
n
N U
N U N n
N n U
N n U N U U
U V
N U N U

=




=


+
+
 
= ⇒ ⇒ = ⇒ =
 

−
 
=
 
−


+

= = ⇒ = ⇒ =


,a
Câu 16$*u*+i !(-8;t+(9/8L'8*M (BO<@
=*++(9/8K@"35v?(c8OPU89GK@C5U8=*+
+(9/8K@"3.v?(8SOPU89GK@•5U8=*++(
9/8K@"$
n?15va?132.v?1D2.v]?1.v
%789:$
!-$
1D
3
1 1
3
3
3
3
3 3
1 1
1 1

3 3
1 1 1 1 1 1
35
C5.
3>5
C5 3.
>
•5 ‘ 3>5 •5 1.5 ‘ 1.5 35
? ‘ 132.
3>5 3>5
N
N U
N
N
N
N
N U
N U
N U
N NU U
U V
N U N N U U


=


+



⇒ = ⇒ =


+

=
= ⇒





− −
= = = ⇒ = ⇒ =


,a
Câu 17$B-OPU8(BO<@8@15"l(BK@?!
*l((BO<@j 8(Ni !(-*++(9/8s
1
y335v?+
;XA!(BO<@";
1
≈5(BK@;
3
≈3”?&oL^LV€kT(!!
V9 9U8•( Ki&?!*l((BK@j7*+;Xy35”=
*++(9/88J!!*l(('K@F8! )(–
n?1dv€ a?33v€ ?35v€ ]?3>v?
%789:$

++(9/88J!!*l((BK@*RX$
1 1
3 3
3
15 33
15
U U
U V E
U
= → = = =

%f8*B9U8*+T(!(BK@LP7*);X$
3
3
3
1
E
I A
R r
= =
+

 *-*++(9/88J!!*l((BK@$s—
3
y
3
?I R
y35v?
,?
G(1d: B-*++(9/83*l((BO<@"335V2

(BO<@-1155U89G?K@8N3(B9G?(B18N>>5U89G
7*+;X
1
y15”€(B38N335U89G7*+;XR
2
yD”?V%f8
*B9U8*++(9/8; 8(BK@–
%789:$
,"l"%I9U8*+; 8(BK@K1K3"l"%I"w
13
2w
33
?
%f8*B9U8*+; 8(BK@$ w
3
y

w
13
z

w
33?
!-$
1d
13 13 1 13
13
1 1 1
? >>5?335
dd

1155
N U U N
U V
N U N
= ⇒ = = =
?

13
13
1
dd
d2d
15
U
I A
R
= = =
33 33 1 33
33
1 1 1
? 335?335
>>
1155
N U U N
U V
N U N
= ⇒ = = =

33
33

1
>>
C?3
D
U
I A
R
= = =
?
vw
3
yd2dzC23y1.n?
2. Dạng 2 : Máy biến áp có tải .
Câu 1$  B-+(O(@d5˜?(BO<@-155U82(B
K@-355U8?&O<@"V%X82*u !*l((BO<@*+i !
(-8;t+(9/8"155vlO'.5`?!*l((BK@P7B
(B9G-*+;X.5
Ω
2*BWS"
52.
π
{|?%f8*B9U89)+(9/8
&O<@8;t$
n?.na?15n?3n]?32.n
%789:$

3 3 3
3 3
3 3
1 1 3

3
3
1
1 1 1

155 155
355{ | 3 3{ |
 355
d?.5
52d .{ |
155?
L
U U
U V I A
U U
R Z
I R
H I A
U I I
= ⇒ = ⇒ = ⇒ = =
+
= ⇒ = ⇒ =
 ,n
Câu 2$B"#%X8-(BO<@
1
y1555U8*%IP
*++(9/8L'8*Ms
1
y>55v?K@8N3(B
3

y.5U82
6
y155
U8?J!!*l(
3
*@(7B*+;Xy>5
Ω
28J!!*l(
6
*@(-B*+
;X—y15
Ω
? 9U8*+*+"('q8!?%f8*B9U8*++(9/8
&; 8(BO<@"$
1•
n?521.5na?52>.5n?52>3.n]?5251.n
%789:$
3 3 3
3 3
1 1 3
6 6 6
6 6
1 1 6
1 1 3 3 6 6 1 1
>55 1555 35
35{ | 52.{ |
.5 >5
>55 1555 >5
>5{ | >{ |
155 ‘ 15

>55? 35?52. >5?> 52>3.
sc tc
N U U
U V I A
N U U R
U N U
U V I A
U N U R
P P U I U I U I I I A

= ⇒ = ⇒ = ⇒ = = =




= ⇒ = ⇒ = ⇒ = = =


= ⇒ = + ⇒ = + ⇒ =
,
Chú ý:L s
12
3
1
N
N
2&K@P02*RV
1
2
3

!"%O!($
3 3
3 1 3
3 3
1
3
3
3 3 1
1
?
{ |
? € –
L C
N U
U U I
N
R Z Z
P
P I R H P
P

= ⇒ =

+ −



− = ⇒ =



Câu 3$ B-+(O(@•5˜?(BO<@-355U82(B
K@->55U8?(BO<@P7*+i !(-8;t+(9/8
1.5v?!*l((BK@P7B(B9G-*+;X &*B8•5
Ω
S
L8"135
Ω
?'8O(@&O<@"$
n?1.5Œa?6C5Œ?3.5Œ]?>55Œ
%789:$
3 3
3
1 1 3
3
3
3
3
3 3
3 3
3 3 3
3
1
1 1
1.5 355
655{ |
>55
? 655 ?•5
? 6C5{Œ|
•5 135
{ |

6C5
52• >55{Œ|
L
N U
U V
N U U
U R
P I R
R Z
P
H P
P P
= ⇒ = ⇒ =
⇒ − = = =
+
+
= ⇒ = ⇒ =
,]
Chú ý:(&K@P7-8*8P8!({s
*
Ž
*
|8N9G
jO 8O 82;)x9G--8-8*™*(O8=%f8=$
35
3 3 3
1 1
3
3 3
1 1 1

3
? ?
? ?
?
?
d
d
d
d
d
P m n P N U
N U
P
I m I m
P P
U
H
P U I
U nU

=

=


 
= = ⇒
 
 
= =

 
=


Câu 4$(BO<@A!B8N1155U8*%Ij &8
*+i !(?(BK@8N335U89GP735-8*8P8!(-LV
+(13vŽ1dŒj.9HO 8O 8;)x9H->-8*™?a-8*™
O8=%f8-+(O(@A!•C˜?%f8*B+(9/8T(!(B
O<@K@"l"%I"$
n?12.C3.nD2.na?D2.n12.C3.n
?Cn12.C3.n]?12.C3.nCn
%789:$
!-$
  
3 3 3
1
1 1 1
3
3 3
1
1 1 1 1
3
? ? 35?1d 6C5{Œ|
335 >d
3>5{ |
1155
1d
? ? .? D2.{ |
6C5
13

52•C 12.C3.{ |
? 3>5?
? >?13 >d{ |
d
d
d
d
d
P m n P N U
U V
N U U
P
I m I m A
P P
U
H I A
P U I I
U nU V

= = =

= ⇒ = ⇒ =


 
= = = = ⇒
 
 
= = ⇒ = ⇒ =
 

= = =


,n
 Chú ý :(&K@P7*B8<*+{
? ? OP U I c
ϕ
=
|=%f8=
3 3
3
1 1
3
3 3
1 1 1
3
? O
?
N U
P P
N U
P
I I
P P
U c
H
P U I
U U
ϕ


=

=


 
= = ⇒
 
 
= =
 
=


Câu 5$B&+(O(@•5˜-„OP8J!OPU89G(BO<@
K@"32.?8%f!j !*l((BK@B*B8<335v6•CŒ2-+
OP'8O(@52d?(*B8< &*B8=%f8=-%f8*B+(9/8; 8
(BO<@K@"l"%I"$
n?52dn32.na?1n12Cn?52dn323.n]?1n32.n
31
%789:$
!-$

3 3 1
3
1
1 1
3
3 3
1

1 1 1 1
3
6•C{Œ|
32. 5{ |
335
6•C
323.{ |
6•C
? O 335?52d
52• 52d{ |
? 5?
335{ |
N U U
P P
U V
N U
P
I I A
P P
U c
H I A
P U I I
U U V
ϕ

= =

= ⇒ = ⇒ =



 
= = = = ⇒
 
 
= = ⇒ = ⇒ =
 
= =


,
Câu 6$B&"V%X8-„OP8J!OPU89G(BO<@(BK
@"32.n?8%f!j !*l((BK@B9B8<335v>>5Œ2-+
OP'8O(@"52d?(*B8< &*B8=%f8=%f8*-+(9/8; 8
(BO<@K@"l"%I"$
%789:$
!-$
3 3 1
3
1
1 1
3
3 3
1
1 1 1 1
3
>>5{Œ|
32. 5{ |
335
>>5
32.{ |

>>5
? O 335?52d
1 52d{ |
? 5?
335{ |
N U U
P P
U V
N U
P
I I A
P P
U c
H I A
P U I I
U U V
ϕ

= =

= ⇒ = ⇒ =


 
= = = = ⇒
 
 
= = ⇒ = ⇒ =
 
= =



,n
Chú ý$(9/8'8K
1 1 3
3 3 1


U I
U I
= =
==;!LT(SO!w
1
y1n?; 8
;%f8I'8K;)S"
1 1 3
3 3 1

O

U I
c
U I
ϕ
= =
Câu 7$B-"h*PiK88N.%8„-3
*%IT(@3(B9G?j1(B9G *+i !(=*%f8OK
o9 -O;!L'8t ;!8 *%I!*( 3U"&?j
(B1 *++(9/8135v=X(B3L*RX-*)+(9/8"s
3

?
j(B37*++(9/86s
3
=*++(9/8X(B1L*RX"
n?332.v a?C5v?65v]?>.v
33
%789:$
!-$

|{.233
1.
6
?
1.
135
1
?
1
‘
3
‘
33
3
‘
33
‘
11
VUUU
U
UU

n
U
n
U
==>=
−−
=>=
−−
y†,n
Chú ý:9/8'8K;)=*+;XA!(B9GL'8
*8LR o'8"L^LV?((BK@*RXU(BO<@-*+
;X(l=-Ri[*+ 
1
U

GP;);)(BS(l0$









=+==>+=
R
LL
LRLR
U

U
R
Z
UUUUUU
333
11

„-ls
0
8G;!+%I8SK8*+o)'8K
"E"$
3
1
3
1
N
N
U
U
=
Câu 8$(BO<@A!B"V%X8(BO<@-
1 
y1155
U8(BK@-
3
y3355U8?]q89G9:-M8*+;X*RP3
*l((BO<@7*+i !(-8;t+(9/8M*t"
s
1
yd3v=LL'8PS*++(9/88J!3*l((BK@"s

3
y
1C5v?„OP8J!*+;X(lSL8Z
0
A!(BO<@"
n? 521•a?521.?52>3 ]?5253.
%789:$
!-$

1
3 3
3 3 3 3 3 3
1
1155
d5{ |
1C5 3355
d3 d5 1d{ | 5233.
L L
L
R
L R R R
L L
U N U
U V
U N
U
R
U U U U U V
Z U
= ⇒ = ⇒ =

= + ⇒ = + ⇒ = ⇒ = =
,]
Câu 9$(BO<@-1155U89G(BK@-3355
U8?P3*l(A!(BO<@7*+i !(>5v.5`?(BO<@-
36
*+;X(l6šSL8>š?++(9/88J!3*l((BK@L
*RX"
n?d5v a?D3v ?C>v ]?63v
%789:
!@$
LR
L
R
L
UU
R
Z
U
U
>
6
6
>
==>==
3
3 3 3 3 3 3
1
1
3
3 3 3

6
>5 63{ |
>
63 1155
C>{ |
3355
L R L L L
L
U U U U U U V
U N
U V
U N U

 
= + => = + => =

 ÷

 


= => = => =


,?
E#$
•
-OPU89GX(BO<@!*M!9q8$








±
=
=
3
1
‘
3
1
3
1
3
1
N
nN
U
U
N
N
U
U
•
-OPU89GX(BK@!*M!9q8:








±
=
=
1
3
‘
1
3
3
1
1
3
N
nN
U
U
N
N
U
U
Câu 10$B-OPU8(BO<@8@15"l(BK@?
!*l((BO<@j 8(Ni !(-*++(9/8s1y335v?
+;XA!(BO<@";
1
≈5(BK@;
3

≈3”?&oL^LV€kT(!
! V9 9U8•( Ki&?!*l((BK@j7*+;Xy35”
=*++(9/88J!!*l(('K@F8! )(–
n?1dv€ a?33v€ ?35v€ ]?3>v?
3>
%789:$
++(9/88J!!*l((BK@*RX$
1
3 3
33
15
U
U V E
= = =

%f8*B9U8*+T(!(BK@LP7*);X$
3
3
3
1
E
I A
R r
= =
+

*-*++(9/88J!!*l(('K@s—
3
y
3

?I R
y35v?
,
Câu 11$B"#%X8-Ly35?jO 8O 8 !*l((B
K@!-8*™OI*P-813vCŒ=*™O8=%f8?%f8
*B9U8*++(9/8T(!(B9GO<@L*-"
 n?1435n? a?52Cn? ?1413n? ]?35n?
%789:$
%f8*B9U8*+X(BK@"$
3
C
3? 3? 1
13
P
I A
U
= = =

v%f8*B9U8*+X(BO<@"$
3
1 3
1
? 35?1 35
I
k I k I A
I
= ⇒ = = =
,]?
3. Dạng 3 : Công suất, hiệu suất, hệ số của máy biến áp.
Câu 1$B+(O(@"•C˜O-U8(PO<@K@"!•

U813.5U82'8O(@15LŒo&8*+i !(?a*++(
9/88Q!!*l((BO7@"1555v+OP'8O(@A!(BK@"52d?
'8O(@*%IX(BK@%f8*B+(9/8; 8(BK@"l
"%I"$
n?•C55ŒCna?•C5Œ1.n
?•C55ŒC5n]?•C5Œ3>n
%789:$
!-$
3.