JPS6231577B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pole-to-pole connection device for field coils in a rotating electric machine, and is particularly suitable for a turbine generator for load adjustment during day and night, which has a large number of startups and stops. relating to the connecting piece.

As shown in FIG. 1, the rotor of this type of turbine generator is mainly composed of a rotor body 1, a rotor shaft 2, a field coil 3, a retaining ring 4, a wedge 5, etc. Adjacent field coils 3 are electrically connected by coupling both ends of connecting pieces 6 with silver brazing or the like. In this example, the connecting piece 6 is attached to the outer diameter side of the field coil 3, but on the contrary, it may be attached to the inner diameter side of the field coil 3.

As shown in FIG. 2, the connecting piece 6 is a connecting element 7 made of a rectangular copper or copper alloy thin plate.
It is constructed by laminating a plurality of sheets of
The flexible portions 6b each have a
This prevents overheating due to the current flowing between the poles, and allows relative movement between adjacent field coils 3 to be absorbed by expansion and contraction of the flexible portion.

Incidentally, the connecting piece 6 undergoes expansion and contraction displacement each time the turbine generator is started or stopped, and this will be explained with reference to FIGS. 3 and 4.

FIG. 3 is a side view of the rotor of the turbine generator viewed from the axial direction. Now, when the generator enters the operating state from the stopped state shown in FIG. 3 and the rotor rotates, the diameter of the retaining ring 5 decreases due to the centrifugal force caused by the rotation of the field coil 3 and the retaining ring 4. increases and is displaced radially outward by ΔR. Along with this, the field coil 3 is also displaced, and the field coil 3
The inner diameter of the lowest turn 9 located most radially inward in
r ₀ is also △ outward in the radial direction, as shown by the chain line in Figure 4.
Displaced by R. The fact that each of the lowest turns 9 of the adjacent field coils 3 is displaced radially outward in this way means that the circumferential spacing between these lowest turns 9, that is, the span of the connecting piece 6, As shown in the figure, this means an increase in span from S ₁ to S ₂ , so _the connection piece ₆ is
δ). This kind of forced displacement is repeated every time the generator is started or stopped.
Furthermore, while the rotor is rotating, centrifugal force is also acting on the connecting piece 6 itself.

Next, regarding the stress acting on the connecting piece 6 due to the centrifugal force of the connecting piece 6 itself, FIGS.
This will be explained using figures.

FIG. 5 is an enlarged detailed view of the main part of FIG. 3, and FIGS. 6 and 7 are explanatory views showing deformation and stress states of the connecting piece shown in FIG. 5 due to centrifugal force, etc. In these figures, the same reference numerals as in FIGS. 1 to 4 indicate the same or equivalent parts, 10 is a piece made of a conductive material, 11 is a spacer made of an insulating material, and 7c is a connecting piece 6. Laminated connection piece 7
Of these, there is an intermediate connecting piece laminated in the middle.
In addition, in FIG. 7, in order to simplify the explanation, the deformation and stress state of the intermediate connecting piece 7c will be explained instead of the connecting piece 6.

When the centrifugal force f directed in the outer radial direction R of the rotor due to its own weight and the forced displacement force in the circumferential direction are applied to the intermediate connecting element 7c, the intermediate connecting element 7c
c is deformed as shown by deformation line X in FIG. As can be seen from this, a bending moment M acts on the intermediate connecting piece 7c due to its own centrifugal force f,
Accompanied by large deformations. Therefore, the stress (strain) is considerably large at the flexible part side end A of the brazed part 6a of the connecting piece 6 and the contact part B with the spacer 11, and if the material of the connecting piece is copper, , the size far exceeds its yield point (yield strength), and the cumulative number of startups and stops of the generator is on the order of several hundred to thousand times, and cracks occur in these parts, especially in the flexible part side end A. However, there was a fear that this would progress due to startup and stoppages and eventually lead to a total rupture accident.

An object of the present invention is to provide a highly reliable pole-to-pole connection device for field coils in a rotating electric machine, which eliminates the drawbacks of the prior art described above and prevents connection pieces from breaking even after many startups and stops. There is something to do.

In order to achieve this object, the present invention provides a flexible portion of a connecting piece with two spaced-apart, oppositely arranged flexible portions extending radially outwardly of the rotor from both end coupling portions through respective bent portions. Consisting of a straight part and a central arcuate part extending radially outwardly and extending over each radially outer end of the two straight parts,
A contact member is provided that abuts on the outside of the rotor in the radial direction at the bent portion, so that the stress applied to the flexible portion due to its own centrifugal force or the like becomes almost only a tensile component. do.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 8 is a front view of an inter-electrode connecting device according to an embodiment of the present invention, FIG. 9 is an explanatory diagram showing the state of stress at the end of the flexible part of the connecting piece in this inter-electrode connecting device, and FIG.
FIG. 0 and FIG. 11 are explanatory diagrams showing deformed states of the connecting piece, respectively. In these figures,
The same reference numerals as in FIGS. 1 to 7 indicate the same or equivalent parts.

In this embodiment, the connecting piece 6 is conventionally
It is constructed by laminating a plurality of connecting pieces made of rectangular copper or copper alloy thin plates, and has brazed parts 6a at both ends and a flexible part 6b in the center. However, the shape of the flexible portion 6b is different from the conventional one. That is,
The flexible portion 6b of the connecting piece 6 of this embodiment consists of a central arcuate portion 6b ₁ and two linear portions 6b 2 connected to both sides of the central arcuate portion 6b ₂ and extending in the direction of the centrifugal force acting on itself, that is, in the radial direction. The brazed portions 6a at both ends are bent approximately at right angles to the straight portion _6b2 . Further, on the outer radial direction R side of this bent portion 6c, the piece 10
A protrusion 10a having a curved surface r is in contact with the protrusion 10a.

In the pole-to-pole connecting device configured in this way, even if the centrifugal force f and the forced displacement force in the circumferential direction are applied to the connecting piece 6, the linear part _6b2 is provided and the bent part 6c is Due to the combination of the fact that the protrusion 10a of the piece 10 having the curved surface r is in contact with the outer radial direction R side, as shown in FIG. No bending stress acts on the end of the flexible part, and most of the centrifugal force f
Only the tensile stress σ _f corresponding to σ f will act.

Also, as seen in the deformation line Y in Figure 11,
There is almost no deformation of the intermediate connecting piece 7c (here, to simplify the explanation, the intermediate connecting piece 7c is shown instead of the connecting piece 6), and the amount of forced displacement is only δ/2. Even with this forced displacement, sufficient flexibility can be ensured by increasing the length of the straight portion _6b2 . Therefore, the stress (strain) applied to the intermediate connecting piece 7c is also reduced, and even when the material is copper, it does not exceed the yield stress (yield strength), and the fatigue life due to starting and stopping of the generator is also reduced. It has a long life of more than 10,000 cycles. This was confirmed through experiments.

As explained above, according to the present invention, it is possible to reduce the stress applied to the flexible portion of the connecting piece due to its own centrifugal force, etc. The fatigue life can be significantly increased and the reliability of the inter-electrode connection device can be improved.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the rotor of a turbine generator, Fig. 2 is a perspective view of a conventional connecting piece, Fig. 3 is a side view of the turbine generator as seen from the axial direction, and Fig. 4 is a view of the field coil. An explanatory diagram showing the behavior during the lowest turn and rotation of the connecting piece, Figure 5 is a front view of a conventional inter-electrode connecting device, and Figures 6 and 7 are explanatory diagrams showing the deformation and stress state of the connecting piece. FIG. 8 is a front view of an inter-electrode connecting device according to an embodiment of the present invention,
FIG. 9 is an explanatory view showing the stress state of a flexible piece of a connecting piece in the same pole-to-pole connecting device, and FIGS. 10 and 11 are explanatory views showing deformed states of the connecting piece, respectively. 3... Field coil, 6... Connection piece, 6a...
Brazing part, 6b... Flexible part, 6b ₁ ... Central arcuate part, 6b ₂ ... Straight part, 6c... Bent part, 7c...
Intermediate connection piece, 9... lowest turn of field coil,
10... Piece made of conductive material, 10a... Tip contact portion.

Claims (1)

[Claims] 1 Among the plurality of field coils provided at intervals on the rotor, between adjacent field coils, a flexible portion formed by laminating a plurality of connecting pieces and both ends In the electrically connected connection piece consisting of a joint part, the flexible parts of the connection part are spaced apart from each other and extend outward in the radial direction of the rotor from the both end joint parts through respective bent parts. It consists of two straight parts facing each other, and a central arcuate part extending radially outwardly from each of the two straight parts, and extending outwardly in the radial direction of the rotor at the bent part. A pole-to-pole connection device for a field coil in a rotating electrical machine, characterized by having a contact member that comes into contact with the pole.