Note: Descriptions are shown in the official language in which they were submitted.
Field of the Invention
The present invention relates to a vertical synchronous
electric machine, and more particularly to rotors of vertical
hydro-generators.
The present invention can most advantageously be used
for large size vertical hydro-generators having a laminated
pole-carrying rim detachable from the rotor frame.
Background of the Invention
Some prior art constructions of`rotors for vertical
hydro-generators permi~ detachment of the rim with pole-pieces
from the frame of the rotor as the hydro-generator is assembled
or disassembled in the well of the hydraulic plant. It arises
from the tendency to place less stringent requirements on the
load-carrying capacity of the assembly equipment. This dis-
connection feature is provided by a removable support means
for supporting the pole-carrying rim after the rotor of the hydro-
generator has been completely assembled. In one such rotor of
a vertical hydro generator/cf. Inventor's Certificate of the
U.S.S.R. No. 429490/, comprising a shaft and a rame with wedge
strips attached thereto, the strips have provided in their lower
portion a horizontal transverse slot wherein a support means is
disposed for supporting a rim with poles. The support means is
formed by a member with a pair of longltudinal projections
essentially of a channel section with one of its legs shortened,
and interlocked with the lower portion of the wedge strip as a
result of the upper shortened projection of the member engaging
said slot provided on the inside oE the wedge strip. In this
case the end of the wedge strip is enclosed, from the bottom,
by the lower elongated projection extending slightly beyond the
outside surface of the strip to provide a support for the rotor
rim.
One disadvantage of this construction consists in the
fact that the bending st~esses borne by the eloncjated support
projection due to tlle mass of the po]e--carrying ri.m may be
si~nificant, since the distance between the point of application
of forces exerted by the mass of the rim and the point of a-ttach-
ment of the support means to the wedge strip is comparatively
large. Tllis is liable to result in deformation of the supporting
projection and consequently in the axial displacement of the
motor rim.
Another drawback of the construction is a difficulty
1.0 encollntered in fabrlcation of the support means: in order to
prov;.de satisfactory assembling of the device, it is necessary
that the mating parts be shaped to conform to each other, in
particular, at least the horizontal slot formed in the wedge
strip should be shaped exactly to match the upper projection of
the support means inserted into the slot. Moreover, in order
that the hori~ontal slot be cut on the inside of all. the wedge
strips, the frame of the rotor has to be turned through 1~0
clegrees, in the vertical plane with respect to its working
position, so as to permit ready access for the cutting tool to
2~ the portion of the frame to be machined. Another disadvantageous
feature is anincreaseci amount of the material expended for
providing larger dimensions of the lower portion of the wedge
strip on the inside thereof, which is required for mounting and
securing -the support means at the point.
It also will be noted that when disassembling the rotor,
the support means for supporting the pole-carrying rim sometinles
has to be detached from the wedge strip of the frame, approaching
from the side o~ the hydro-generator brake plate, which may be
inconvenient.
Summary of the In~ention
It is an object of the present invention to provide a
rotor of a vertical hydro-genera-tor, equipped with a simple
,a~
and reliable dismountable means ~or supporting the polc-carrying
rim, the support means being mounted in the lower portion of each
wedge strip of the rotor frame.
Another object of the invention is to provide a rotor
for a vertical hydro--generator, with a dismountable support means
designed so as to reduce tlle stress imposed thereon due to -the
mass of the pole-carrying rim.
Still another object of the present invention is to
provide a rotor of a vertical hydro-generator with a dismountable
~0 support means permitting an easy and convenient assembly and
disassembly of this rotor.
A further object of the invention is to improve
operational reliability of the vertical hydro-electric generator.
With these and other objects in view there is proposed
a rotor of a vertical hydro-generator, comprising a shaft and a
frame with wedge strips attached thereto having provided in
their lower portion a horizontal transverse slot with a support
means disposed therein for supporting a pole-carrying rim, wherein
according to the invention the support means is formed by
oppositely directed wedges arranged within said slot provided
in outer side of the lower portion of each wedge strip, the
wedges partially projecting beyond the slot and extending
towards the rim.
The advantage of the proposed rotor of a ver-tical hydro-
generator is that in the support means for the pole-carrying
rim, the shape and dimensions of the ~ppositely direc-ted wedges
forming part of the supporting structure need not exactly match
those of the horizontal transverse slot wherein -they are disposed.
In addition, such construction of the support means tends to
minimize the hazard of deformation of the load-sensing member,
which would bring about the displacement of the rim with respect
to the frame.
, ~ -
It is preferable that -the oppositely directed ~edges he
disposed in the horizontal transverse slot o~e abcve anctl~er and
arranyed with t~leir slopes lying in the direction from the frame
periphery to the rotor sha~t, at least one of these wedges
being bolted to the wedge strip.
As a result of tihis arrangemen-t of the cp~csitely
directed wedges, an additional fcrce is caused to be applied to
the pole-carryi"g rim, as the wedges are driven into the
horizontal slot, wllich ensures a tighter fit of tlle rim against
.1.0 the ~rame -to counteract the tendency of tl~e ~edges tG self-
loosen ul~der the influence of dynamic loads during operaticn of
tne hydro-~enerator.
In one embodiment of the rotor of a vertical hydro-
generator, on that side of each of the oppcsitely directed wedges
facing the bottcm of t~e horizcntal transverse slot, there are
provided vertica~ f]utes ccmbired to fcrm a single vertical slot
after said wedges have been assembled in the horizontal transverse
slot.
The ~ertical flutes provided in the oppcsitely di~ect~
wed~es of the support means will permit arrangement of stay
taper keys along the entire length of the wedge strip and will`
enable the machining operation, such as using a mandrel, designed
to eliminate the surface roughness tending to occur, when
assembling the laminated rim, on the surface of the grooves
formed in the rim for receiving the taper keys, to be performed
throughout the length of the grooves, after the rim has been
mounted on -the support means.
In another embodiment of the rotor of a vertical hydro-
generator, the oppositely directed wedges are formed by a pair of
sets of wedges arranged in a spaced-apart rela-tion within the
horizontal transverse slot.
The embodiment of the oppositely directed wedges of
5 -
the support means in the form of two se-ts of we~ges ensures an
ease of manufacture as well as separa-te adjustment of the wedge
sets in t~le slot relative to the stay taper keys of the wedge
strip.
Brief Description of the Drawin~s
These and other objects and advantages of the present
invention will be apparent from the following detailed description
of its preferred embodiments with reference to the accompanying
drawings in which:
Fig. 1 shows, in diagrammatic form, a radial cross
sectioll througll a portion of the rotor disposed in the rotor
area of the hydro-generator enclosure, according to the invention;
Fig. 2 is an enlarged view of the lower portion of the
wedge strip attached to the rotor frame with a support means for
supporting the rim of the rotor as illustrated in Fig. 1, a
radial cross section;
Fig. 3 is a perspective view of the wedge strip attached
to the rotor frame, with a support means mounted thereon and one
punching of the rotor core;
Fig. 4 is a perspective view of another embodiment of
the support means mounted on the wedge strip of the rotor Erame.
It will be understood that all the accompanying drawings
are represented in a schematic form and are merely illustrative
of specific embodiments of thepresent invention without any
restrictions imposed on the dimensions and the like.
Detailed Description of the Invention
Referring now to Fig. 1, the rotor of a vertical hydro-
generator according to the present invention, disposedin a rotor
area 1 of the generator enclosure comprises a shaft 2 and a frame
3 including a central portion in the form of a hub 4 fitted onto
the shaft 2 and a plurality of radial spokes, one only of which
is shown in the drawing at 5, which spoke is secured to the hub
~ . .
-- 6
4 by butt plates 6 with coupling s-tuds 7. Wel~ed -to the outslde
portion of the spoke 5 is a wedge strip 8 having a horizontal
transverse groove 9 cut in the top portion thereof and a vertical
longitudinal groove 10 extending along the entire length of the
strip.
Facing tne vertical groove ]0, in a laminated rim 11
carrying poles 12, there is provided a similar groove 13 which
combines with the groove 10 to form a vertical keyway for re-
ceiving stay taper keys 14 inserted therein with a tight fit.
These ~eys together with a fastening strap 15 inserted into -the
l~orizontal groove 9 provide for the laminated rim 11 with the
poles 12 to be secured to the wedge strip 8 and hence to the
frame 3 of tne rotor, at the same time preventing -the rim 11 from
being displaced with respect to the frame 3 both in the radial
and in the tangential direction during operation of the generator.
To prevent displacement of the laminated rim 11 with
the poles 12 downward, a support means is provided on the lower
portion of the wedge strip 8, including oppositely directed
wedges placed one on top of ano-ther, such as an upper wedge 16
and a lower wedge 17. The oppositely directed wedges 16 and 17
are driven into a straight horizontal slot 18 formed in the lower
portion of the wedge strip 8 on the outer side -thereof and
transversely thereto, these wedges (as shown inFig. 2) being
arranged in the slot 18 so that their slopes are directed from
the periphery of`he frame 3 to the shaft 2 of the rotor.
In this arrangement the vertical plane at one end of -the upper
wedge 16 bears against the bottom of the slot 18, while the other
end of the wedge 16 projects beyond the slot towards the
rim 11, the projecting portion of the wedge 16 serving as a
support for the laminated rim 11 with'-he poles 12. The lower
wedge 17 is positioned in the slot 18 so that a gap exists
between that side of the wedge facing the bo-ttom of the slot
18 and this bottom. The lower wedge 17 is secured to the wedge
strip 8 by means of field bolts, one only of which is shown in
tihe drawing at 20, the bolt being inserted into a nole 21 in -this
strip and screwed into a through threaded hole 22 formed in the
wedge.
In -the embodiment of the present invention shown in
Fig. 3 those sides of the oppositely-directed wedges 16 and 17
facing the bot-tom of the horizontal slot 18 in the wedge strip 8
have provided therein vertical flutes 23. When the wedges 16 and
17 are assembled in the slot 18, they form a single vertical slot
w.ith its cross section shaped to match a cut-out 24 made in a
punciling 25 of the laminated rim 11 and forming part of the verti-
cal yroove 13 facing tne vertical groove 10 in the wedge strip 8.
The vertical slot so produced together with the vertical groove
10 provides in turn, a keyway to receive the taper keys 14 in the
lower portion of the wedge strip 8.
In -the embodiment of Fig. 4, the oppositely directed
wedge 16 and 17 are arranged in.the form of two sets 26 and 27
of such wedges mounted in the slot 18 witll the gap 28 formed
tilerebetween, whicil together Witil the vertical groove 10 like-
wise defines a keyway for receiving the taper keys 14 in thebottom portion of the wedge strip 8.
Tile assembly of the proposed xotor of a ver-tical hydro-
generator will now be described.
Af-ter tlle laminated rim 11 with the poles 12 (Fig. 1)
has been set on a braking gear 29 of the hydraulic plant, tile frame
3 Witil tne shaft 2 is placed inside the rim 11 and rests upon
a step bearing 3a. In this case the vertical grooves 10 in the
wedge strip 8 on each spoke of the frame 3 are aligned with the
corresponding vertical grooves 13 in the rim 1.1, and the lower
edge of the rim is positioned, by means of the jacks (not shown)
of tlle braking gear 29, slightly above the plane of -the top
(according to the drawing) side face of the horizon-tal slot 18
8 --
in the wedge strip 8. Tlle lower f~-cdge 17 of the support means is
then driven into tlle slot 18, as shown in ~ig. 2, (bu-t not as
deep as the bottom of tlle slot), the upper wedge 16 is placed
on top of the lower wedge 17, and the wedging operation is per-
formed. Tile oppositely directed wedges 16 and 17 are driven in
until the end surface and tlle upper horizon-tal surface of the
upper wedge 16 is brought into contact with the bottom ana the
top (according to the drawing-) side face of the slot 18,
respectiveiy, and until the re~uired tightness of fi-tting the
wedges in this slot is obtained. Fina]ly, the lower weage 17
is loc~ed in pOsitiOIl by the bolts ~0O When assembled, both the
wedge 16 an~ the wedge 17 slightly project from tile slot 18, as
aforementioned.
~ hen the oppositely directed wedges 16 and 17 (Fig. 1)
are in place in the slot 18 provided in the wedge strip 8, the
laminated rim 11 with the poles 12 is lowered by the previously
mentioned jacks and set upon the support means, in particular,
upon the projecting part of the upper wedge 16. Subsequently
tlle stay taper keys 14 are inserted from the top into the keyway
formed by properly aligned vertical grooves 10 and 13 provided
in the wedge strip ~ and in the laminated rim 11, respectively,
and -these keys are driven in place, wnile simultaneously centering
the rim 11 with respect to the frame 3. The resultant position
of tne rim 11 is locked by the fastening strap 15 inserted into
the horizontal groove 9 cut in tne upper portion of -the wedge
strip 8.
For certain purposes such as dismantling of the hydraulic
turbine generally mounted below the hydro-generator, or for
service and repair functions performed with components of the
hydro-generator, including the frame 3 or the laminated rim 11,
it may be necessary to detach the frame 3 with the shaft 2 from
the rim ll. The disassem~ly of the rotor will now be described.
After tlle hydro-~enerator has been stoppe~, ~he rim 11
of the rotor is set on the braking gear 29 which bears in this
case, the complete mass of -the rotor. The rim 11 is then heated,
in the normal fashion, up to a temperature on the order of
~0 ~o 50~C to facilitate disassembliny of the wedge joints
connecting the frame 3 with the rim 11. When the rim 11 has been
uroperly warmed up, the fastening strap 15 is removed from the
horizontal groove 9 in the wedge strip 8 on each spoke of the
frame 3, and the stay taper keys 14 are taken out of the key-
ways defined by the vertical grooves 13 and 10 in the rim 11 and
the strip 8, respectively. The rim 11 thus detached from the frame
3 is subsequently raised by the aforementioned jacks of the
braking gear 29, thereby relieving the support means of the wedye
strip 8 of the stress exerted by the mass of the rim 11 with the
poles 12. The support means is now ready for disassembling.
To do this, bolts, including the bolt 20, securing the lower
wedge 17 to the wedge strip`8 are first withdrawn, and the lower
we~ge 17 is slightly pushed out of the slot 18 using a special
tool inserted into the gap 19 (Fig. 2), in order to loosen the
fit, and both of the oppositely directed wedges 16 and 17 areremoved from the slot. On disassembling the support means, the
frame 3 (Fig. 1) with the shaft 2 is removed from the inner
space of the rim 11 which is left resting upon the braking gear
29 in the area 1 of the hydro-generator.
The assembly and disassembly work carried out on the
proposed rotor of a vertical hydro-generator according to the
present invention, with the~oppositely direc-ted wedges 16 and
17 of the support means, as shown in the embodiments of Fig. 3
and Fig. 4 is essentially similar to that previously described,
except that for the embodiment of Fig. ~, first one set of these
wedges, such as the set 26, is driven into the slot 18 in the
wedge strip 8 or removed therefrom, and then the other set 27,
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which may be convenient for some specific types of vertical
hydro-electric generators. Tlle oppositely directed wedges of the
: support means of the proposed rotor of a vertical hydro-generator
are fabricated from normal construction steel or, in particular
cases, from special steel. In the support means of the ahove
described rotor employed in a vertical hydro-generator of ahout
200,000 kW, the oppositely directed wedges have the following
dimensions: length 172 mm, width 60 mm, height 38 mrn, for the
depth of the slot wherein they are ~isposed equal to 40 mm; and
the slope of the mating surfaces of the wedges is chosen in the
range from 1:5 to 1:10, which practically eliminates the risk
of self-unkeying and prevents the wedges from being pushed out
of the slot when the hydro-generator is in operation. The
support means is capable of withstanding a load of as much as
1000 kg/cm .
In the proposed rotor of a vertical hydro-generator, the
construction of the support means provides an ease of manufacture,
it is convenient to assemble and disassemble and reliable in
operation. It facilitates the assembly and disassembly work on
vertical hydro-generators, particularly of the large-size type,
and saves the time required for installation or repair of a
generator or a turbine incorporated in the vertical hydraulic
plant.
It will be unders-tood that the present invention is not
restricted to the preferred embodiments herein described and
illustrated, and other modifications and embodiments of the
proposed rotor of a vertical hydro-generator are possible without
departing from the spirit and scope of the same as disclosed
in the following claims.
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