Note: Descriptions are shown in the official language in which they were submitted.
104~582
This invention relates to a rotary electric machine having a
cooling structure and in particular to a rotary electric machine in
which a rotor winding of the rotor is cooled.
A conventional rotary electric machine such as a turbine generator
is cooled by introducir.g a cooling medium such as cooling gas into
slots in which a rotor winding is disposed and bringing it into
direct contact with the rotor winding. The rotor winding conductor
plates superposed within the slot have gas inlet and outlet cutouts
alternately formed on each side portion and in the direction of the
conductor plate and diagonal grooves connecting the inlet and outlet
cutouts to each other. A cooling gas introduced from the gas inlet
cutout is passed through the diagonal groove to cool the conductor
plate and exhausted from the gas outlet_cutouts. In the rotary
electric machine of this type, however, the cooling gas introduced
into the gas inlet cutout is leaked from a clearance between the
conductor plate and an insulating plate surrounding he conductor
plate. ~s a resulf, the gzs enters direct ~nto the neighboring
outlet cutout and is exhausted to the outside without contributing
to cooling of the rotor winding. For this reason, an effective
amount of gas is not passed through the diagonal groove. As a
result, the conductor plate is not effectively cooled and the rotary
electric machine fails to exhibit its enhanced performance.
It is accordingly the object of this invention to provide a
rotary electric machine in which a rotor winding is efficiently
cooled by a cooling medium introduced into the rotor.
According to this invention, there is provided a stator and a
rotor: a rotor body having a plurality of slots, a rotor winding
having i~ the 910t a plurality of superposed conductors insulated
from each other and each formed of first and second conductor plates,
the first conductor plate having inlet hole groups each consisting
of at least one inlet hole and outlet hole groups each consisting of
at least one outlet hole, said inlet and outlet hole groups being
alternately provided in two rows in the direction of the axis of the
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L _Or body with the inlet and outlet hole groups in one row oppositely
facin~ ~e inlet and outlet hole groups in the other rows, respecti~ely,
the inlet and outlet of the first conductor plates being respectively
aligned with each other, the first conductor plate having grooves
th~ough which the inlet and outlet holes in one row are connected ~o
the outlet and inlet holes in the other row, respectively, and the
~econd conductor plate being disposed on the grooved surface of the
first conductor plate and having holes in alignment with ~he inlet
and outlet holes in the first conductor plate, and wedges coverin~
the opening of the slot and each having inlets and outlets formed
corresponding to the inlet and outlet holes of the first conductor
plate.
- This invention can be more fully understood from the following
detailea description when taken in conjunction with the accompanyinq
drawings, in whichs
Fig. 1 is a partial cross-sectional view schematically showing
~ rotary electric machine according to one embodiment of this invention
which is provided with a rotary cooling structure for a rotor winding;
Fig. 2 i8 a schematic partial cross-sectional view, partly
broken away, showing a structure for a rotor of the rotary electric
machine in Fig. 1:
Fig. 3 is a cross-sectional view, taken along line III~ITI in
Fig. 1, showing a gas inlet section of a rotor winding of the rotor
in Fig. 2;
Fig. 4 is a partial cross-sectional view, taken along line IV-
A IV in Fig.-~ showing a gas outlet section of the rotor winding of
the rotor in Fig.-t~
Fig. S is a top view showing the rotor winding of the rotor in
Fig. 2:
Fig. 6 shows a modified form of the rotor winding in Fig. 5;
Fig. 7 shows a rotary electric machine according to another
e~bodiment of this invention which has the rotor winding ir, Fig. 6:
~nd
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Fig. 8 is a modified form of a conductor plate in the rotary
electric machine.
A rotary electric machine according to one embodiment of this
- invention will now be explained below by referring to the accompanying
drawings.
Fig. 1 shows a generator 10 according to one embodiment of this
; I invention. m e generator 10 nas a stator 12 and a rotor 14 between
which a clearance 11 is provided. Inner and outer casings 16 and 17
are provided to enclose the stator 12 and the rotor 14. The rotor
14 has at each end a shaft 18 journaled in the bearing 21 and is
rotatably supported by the shaft 18 within the stator 12. The rotor
14 has inlets 20 for suckinq a cooling gas, for exampie, a cool-n~
air or hydrogen gas and outlets 22 for exhausting the cooling gas
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which has been circulated within the rotor 14 to cause a winding of
the rotor 14 to be cooled. The inlets 20 and outlets 22 are radially
formed in the circumference of the rotor 14 and alternately disposed
in the ax$al direction of the rotor 14. A pair of air blowers 24
are provided on the shaft 18 one at each end side of the rotor 14
and adapted to send into the inner casing 16, for example, the
cooling air or hydrogen gas which is cooled within the inner casin~
16 and in a spacing defined between the inner and outer casin~s 16
and 17. Most of the cooling air i6 passed through the clearance il
between the stator 12 and the r~tor 1~ and sent out of the stator 12
through ducts 13. Some of the cooling air sent by the air blower 24
into the inner casing 16 is sent out of the stator 12 through a
stator coil end 19 and meets the cooling gas passed through the
ducts 13. m e cooling gas is passed through the spacing between the
inner casing 16 and the outer casing 17 and comes to the inlet side
of the air blower 2~ through a heat exchanger, not shown, where it
is recirculated. Some of the cooling air present between tne stator
12 and the rotor 14 is circulated through slots 26 (Fig. 2) from the
inlets 20 in the rotor 14 and exhausted from the outlet 22. The so
exhausted air is diffused within the clearance 11 between the statOr
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a ~ the rotcr.
Fig. 2 is a partial cross-sectional view, partly broken away,
8howinq details of the rotor 14. Slots 26 are radially formed in
the circumference of an iron core 15 of the rotor 14 and have a wall
covered with an insulating plate 28. The o~ening of the slot 26 is
closed by a wedge 30. The inlets 20 and outlets 22 are alternately
formed in the wedge 30 in the axial direction of the rotor 14.
Within the slot 26 is received a rotor winding formed of alternately
~uperposed conductor plates 32A and 32~. The conductor plate 32A
has two rows of alternately arranged outlet and inlet holes 3~ ar.d
36 and diagonal grooves 38 which connect the inlet and outlet holes
36 and 34 in one row to the outlet and inlet holes in the other row,
respectively. The respective outlet and nlet holes 34 and 36
communicate with the outlet 22 and inlet 20 respectively through
respective through bores 42 in a creepage block 40 disposed between
the wedge 30 and the rotor winding.
Fig. 3 i8 a cross-sectional view showing the rotor cut along
its vertical plane including the inlet 20 i.e. taken along line III-
III in Fig. 1. Superposed in the slot in the iron core 15 of the
rotor 14 are plate-like conductors 32 forming the rotor winding
which each consist of the conductor plates 32A and 32B. Insulating
plates 44 are each disposed immediately below the conductor plate
32A so as to effect an insulation between the conductors 32. The so
superposed conductors 32 or the rotor ~inding is fixed in 'he slot
26 by the insulating creepage block 40 and wedge 30. The conductor
plate 32 and insulating plate 44 are respectively provided with
elongated holes 35 and 45 which are in alignment with the inlet port
36 of the conductor plate 32A to constitute a cooling gas inlet
passage. The so aligned elongated holes 35, 36, 45 in the respective
conductor plates are made narrower and shorter toward the base of
the slot 26. This permits the cooling gas introduced from the inlet
20 of the wedge 30 through the through bore 42 of the creepage block
40 to be substantially uniformly distributed through the respecti~e
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104858;~ 1
diagonal grooves 38. During the rotation of the rotor t the inlet 20
of the wedge 30 is opened in the direction of rotation of the rotor
14 as indicated by an arrow A so as to introduce more cooling gas
present between the stator and the rotor 14. A projecting member 46
triangular in cross section is formed on the central portion of ~he
uppermost conductor plate 32B and serves to smoothly direct the
cooling gas introduced through the inlet ~0 into the two rows of
passages ~ach of which is constituted by the holes 35, 36, ~5.
Fig. 4 is a cross-sectional view showing the rotor cut along
i~s vertical plane including the outlet 22 i.e. along line IV-IV in
- Fig. 1. The conductor plates 32A and 32B, insulating plate 44,
creepage block 40 and projecting block 46 in Fig. 4 have an arrangement
similar to those shown in Fig. 3. That is~ the outlet hole 34 of
the conductor plate 32A, the hole 33 of the conductor plate 32B and
the hole 45 of the insulating plate 44 are combined to constitute an
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outlet passage for the cooling gas. The cooling gas is exhausted 5
from the o~tlet passage through the th.ough bore 42 of the creepage
block 40 and outlet 22 of the wedge 30 toward the outside. The
outlet 22 of the wedge 30 is opened in a direction opposite t~ the
direction of rotation of the rotor 14 as indicated by an arrow A so
that the cooling gas can be easily exhaustea toward the outside.
i Fig. 5 shows a top plan view of the rotor winding in Fig. 2.
The cooling gas introduced into the inlet hole 36 is passed down the
slot 26 through the inlet passage and directed through the diagonal
groove 38 toward the outlet hole 34.
The operation of the rotary electric machine will now be explained
below.
cooling gas is sent by the air blower 24 (Fig. 1) into the
clearance between the stator 12 and the rotor 1~. As shown in Fig.
30 3 the cooling gas is introduced through the inlet 20 of the wedge 30
into the slot 26. That is, the cooling gas is branched at the
through bore 42 of the creepage block 40 and directed toward two
rows of the inlet passages each formed by the holes 35, 36, 45. The
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104~58;~
- c~oling gas cools the conductor plates 32A and 32B while being sent
down the sl~t 26, and flows from the inlet hole 36 toward the diagonal
groove 38 in the surface of the conductor plate 32~ so that the
conductor plates 32~ and 32B are cooled. Then, the cooling gas is
passed from the diagonal groove 38 through two rows of outlet passages
each formed by the holes 33, 34 and 45 (Fi~. 4) toward the through
bore 42 of the creepage block 40, while cooling the conductor plates
32A and 32B. The cooling gases exhausted from the t~o rows of
outlet passages meet at the hole ~2 of the creepage block 40 and
then are exhausted and diffused into ~he clearance between the
stator 12 and the rotor 14 through the outlet 22 of the wedge 30.
Unlike the conventional rotary electric machine in which the
cooling gas is passed through cutouts provided at each side of the
rotor winding, in the rotary electric machine according to this
invention, the cooling gas is passed ~rough the holes formed in the
rotor winding. As a result, the cooling gas is not ieaked from the
passage formed Dy the ho;es and the cooling gas passed through the
passage is contacted with the entire surface of the holes n the
- oonductor plates for the rotor winding so that the rotor winding can
be efficiently cooled. Thus, the rotary electric machine can attain
an elevated performance.
~ lthough one embodiment of this invention has been explained by
way of example, this invention is not restricted to this embodiment
only and a variety of modifications can be made without departing
from the spirit and scope of this invention. In the embodiment of
this invention, for example, the inlet and outlet holes 36 and 34 in
the conductor plate 32~ which are situated at the higher position of
the slot 26 are made wider and longer than those in the conductor
plate 32~ which are situated at the lower position of the slot ~6.
This arrangement permits the cooling gas to be uniformly passed
through the diagonal grooves in the respective conductor plates 32A.
From the standpoint of manufacture, the inlet and outlet holes 36
and 34 situated at the lower and the higher positions may be formed
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tu have the same dimension~
In the embodiment, the inlet and outlet holes are alternatel~
provided in the conductor plate 32A. However, groups consisting of
a predetermined number of inlet holes 36 and groups consisting of a
corresponding number of outlet holes 34 may be alternately formed in
the conductor plate 32A. As shown in Fig. 6, for example, groups
consisting of four inlet holes 36 and groups consisting of four
outlet holes 34 may be alternately provided in two rows with the
inlet and outle~ hole groups in one row oppositely facing the inlet
and outlet hole groups in the other rows, respectively. The inlet
hole 3~ in tha inlet hole group in one row is connected through a
diagonal groove to the outlet hole 34 in the outlet hole group in
the other row. In this case, it is necessary that the inlet and
outlot of the wedge 30 be provided in a manner to correspond to the
inlet and outlet holes of the rotor winding. This embodiment i5
shown in cross section in Fig. 7. In~~ig. 7, similar reference
numera;s ara employed to designate parts or elements corresponding
to those shown in Fig. 1. In this embodiment, a cooling gas compressed
~; by an air blower 24 is sent direct into the inlet 20 of the wedge 30
to define a gas inlet zone 48 and a gas outlet zone 50. As a result,
there is no chance that a warmed gas from the outlet 2Z of a wedge
30 will flow back into the inlet 20 of the wedge 3~ and be mixed
with a low temperature cooling gas. Therefore, a cooling effect can
be elevated and the arrangement is fitted for a large-capacity -
rotary electric machine.
In the above-mentioned two embodiments the conductors ~2 for
the rotor winding have a two-ply structure consisting of the conductor
plate 32A (first conductor section) and conductor plate 32B (second
,
conductor section). In the large-capacity rotary electric machine
the conductor 32 can be formed to have a three-ply structure consisting
of the conductor plate 32A (first conductor section), ¢onductor
plate 32B (second conductor section) and conductor plate 32C (third
conductor section). In this case, the conductor plate 32C similar
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1 configuration tc the conductor plate 32A is placed on the conductor
plate 32B with the inlet and outlet holes directe~ downward and ~he
diagonal groove is provided in the conductor plates 32A and 32C. As
a result, an air contact surface and a heat transfer surface can be
Incre~sed, thereby attaining an elevated coolinc efficiency.
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