1
LECTURE 5
This lecture moves from reluctance machines to induction machines. The formulae of the
coupling between windingx and windingy which have been developed in chapter 3 will
be applied. The resultant equations are simpler because induction machines are round
rotor machines with a uniform airgap. For example, the inductance matrix of the 3phase
reluctance machine is:
⎥
⎥
⎥
⎦
⎤
⎢
⎢
⎢
⎣
⎡
°
−
+
+
−
°
−
+
−
+
−
°
−
+
°
−
+
−
°
−
+
−
°
−
+
−
+
=
)
240
(
2
cos
)
(
2
cos
5
.
0
)
240
(
2
cos
5
.
0
)
(
2
cos
5
.
0
)
120
(
2
cos
)
120
(
2
cos
5
.
0
)
240
(
2
cos
5
.
0
)
120
(
2
cos
5
.
0
)
(
2
cos
)]
(
[
d
B
A
d
B
A
d
B
A
d
B
A
d
B
A
d
B
A
d
B
A
d
B
A
d
B
A
d
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
θ
θ
θ
θ
θ
θ
θ
θ
θ
θ
(1)
When the saliency is removed by setting b/a=0,
0
)
/
(
5
.
0
.
2
1
3
0
=
=
a
b
B
LR
L
B
πμ
. One
reverts to the simpler equation of the round rotor:
⎥
⎥
⎥
⎦
⎤
⎢
⎢
⎢
⎣
⎡
−
−
−
−
−
−
=
A
A
A
A
A
A
A
A
A
S
L
L
L
L
L
L
L
L
L
L
5
.
0
5
.
0
5
.
0
5
.
0
5
.
0
5
.
0
]
[
(2)
where
a
B
LR
L
A
/
2
1
3
0
πμ
=
Engineers, who work with induction machines, have their set of symbols. The notes will
follow them so much as possible. For the present, only two changes are made:
Up to now, the average airgap is given the symbol “a”. It will be changed to “g”.
Secondly,
a
B
LR
L
A
/
2
1
3
0
πμ
=
is changed to
g
B
LR
M
/
2
1
3
0
πμ
=
. Therefore,
⎥
⎥
⎥
⎦
⎤
⎢
⎢
⎢
⎣
⎡
−
−
−
−
−
−
=
M
M
M
M
M
M
M
M
M
L
S
5
.
0
5
.
0
5
.
0
5
.
0
5
.
0
5
.
0
]
[
(3)
Recall that in Lecture 3Appendix, the inductances of the coupling between windings x
and y are:
)]
(
2
cos
[
x
d
B
A
xx
L
L
L
θ
θ
−
+
=
(319)
)]
(
2
cos
[
y
d
B
A
yy
L
L
L
θ
θ
−
+
=
(320)
)]
2
cos(
)
(cos(
[
y
x
d
B
y
x
A
yx
xy
L
L
L
L
θ
θ
θ
θ
θ
−
−
+
−
=
=
(321)
When b/a=0 so that
0
)
/
(
5
.
0
.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '09
 BonTekOoi
 Cos, Rotor machine

Click to edit the document details