JPS6041540B2 - Gas cooling current collector for AC rotating electrical machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a gas-cooled current collector layer for an AC rotating electric machine, and particularly for a large-capacity turbine generator, the present invention relates to an improvement in a gas-cooled current collector layer for an AC rotating electrical machine, which has a slip ring and brushes are densely arranged on the surface of the slip ring. This invention relates to improvements in gas-cooled current collector layers.

Generally, the current collector layer of an AC rotating electric machine includes a slip ring that is electrically connected to the rotor windings and rotates together with the rotor, and a slip ring that is arranged so as to be able to slide with a predetermined pressing force on the surface of the slip ring. The fixed part and the rotating part are configured to be electrically energized by contact between the two brushes.

In the current collector layer of a normal rotating electric machine of this type, the number of brushes is selected depending on the magnitude of the required current, and that number of brushes are arranged on the slip ring.
When it comes to the current collector layer of an AC rotating electrical machine of W or more, for example, 1000 MW class, the number of Sakaki rings becomes enormous.For example, taking a 1000 MW turbine generator as an example, the slip ring is 400 leg cores x 40 enemies. On the surface, 16 brushes with a sliding surface size of 4 ratios x 25 ribs are required.

In order to arrange a large number of brushes side by side on the emotional surface of a slip ring whose width is limited, that is, the child size is limited, it is necessary to arrange the brushes densely, and therefore the adjacent spacing between the brushes is inevitably large. becomes smaller. Of course, there is no limit to the size of the slip ring, and if you increase the surface area of the slip ring, that is, increase the diameter of the slip ring, or increase the middle dimension (length in the direction of the ball), you can arrange the brushes side by side with ample spacing. It is possible to do so.

However, as mentioned above, increasing the diameter of the slip ring unnecessarily increases the circumferential speed of the slip ring surface.
In other words, a problem arises in how far the sliding portions can slide, and increasing the middle dimension means increasing the axial length of the rotating electric machine, which is also not desirable. For this reason, in the rigid device of this type of large-capacity turbine generator, the brushes are placed adjacent to each other as far as empirically allows, and the slip ring is kept as small as possible according to the required area.

It is fine as long as the current collector layer is small enough to conduct electricity between the rotating and stationary parts, but in order to ensure stable and sufficient current flow, one of the other major problems is cooling. In other words, the slip ring and brush are always in a sliding state, and since a large current flows through the contact resistance part (the contact area between the Arashi U-coat and the slip ring), there is naturally a large amount of friction between them. Heat is generated due to heat and resistance losses. Therefore, the current collector of this type of rotating electric machine sends cooling gas to the sliding portion and its surroundings to remove the generated heat. As described above, as the capacity of AC rotating electric machines increases, the density of the brushes increases, and more efficient and sophisticated cooling devices are required.

Even if it is possible to manufacture a cooling device that is generally efficient, there are limits to the cooling device, and with this type of gas cooling directly connected to the current collector, the amount of cooling gas usually ends up increasing. It is. Even if the amount of gas is increased, if the cooling gas is ejected to the brush section at a far speed, the stability of the brush will be affected by the wind pressure. It has been very difficult to obtain high current collectors. The present invention has been conceived with this in mind, and its purpose is to develop a rotary motor of this type that can be made compact and capable of stably supplying a large current without using a special cooling device or other devices. To provide gas cooling current collector system for electrical machinery. In other words, the present invention divides the brushes that are densely packed on the sliding surface of a slip ring into a plurality of rigid groups in the circumferential direction, and sets the adjacent intervals of the brush groups in all directions around the circumference of each brush group. The initial purpose of It was designed to achieve the following.

The present invention will be explained in detail below based on the illustrated embodiments.

FIG. 1 shows a cross section of a current collector layer 1 employed in a large-capacity turbine generator and its surroundings.

The current collector 1 is provided at the opposite end of the generator and is mainly composed of two positive and negative slip rings 2, a sakaki ring 3, and a cooling device 4. Each slip ring 2
is fixed to the rotating shaft 5 via an insulating layer 10 disposed on its inner peripheral surface, and rotates together with the rotating shaft. The rotating shaft 5 has a bearing 6
is rotatably supported by a flange 7 at one end thereof.
and is coupled to a generator rotor (not shown).
Further, the rotating shaft 5 has a hollow hole 8 therein, and incorporates an IJ cord wire 9 for electrically connecting the slip ring and the rotor winding (not shown). Further, a cooling fan 11 serving as a cooling device 4 is fixed to a rotating shaft 5, and its rotation causes circulation of cooling gas for cooling the current collector layer. An axially extending through hole 18 inside the slip ring 2 is a cooling hole through which a portion of the cooling gas passes to cool the slip ring from the inside.
Further, a brush 3 is disposed on the sliding surface of the slip ring 2 and is supported by a brush holder 12. Brush holder 12
is fixedly supported on a frame 14 via a bus ring 13. A bigtail is pulled out from the brush 3, and the brush is electrically connected to an external power source via this pigtail and the bus ring, but this is omitted here because it is not particularly relevant. The entire current collector layer 1 is covered with a cover 15, through which cooling gas flows as shown by the solid line arrow in the figure.In other words, as the cooling fan 11 rotates, the cooling gas flows through the cover from the cooling gas suction hole 16 provided in the pedestal 14. The gas is sucked into the slip ring 15, and the sucked gas flows through the cooling hole 18 and the cooling portion of the slip ring, removes heat from these portions, and is discharged from the exhaust hole 17 of the mount. slip ring 2,
The funnel 3 placed on the slip ring and the sliding parts of both are cooled in this way, but in this case, the rigid piece 3 is not only arranged side by side on the slip ring, As shown in FIGS. 2 and 3, a large number of brushes 3 are arranged in parallel as follows, and are divided into a plurality of brush groups 3a, 3b, 3c, . . . in the circumferential direction.

Note that the brush holder is omitted in the figure. In particular, these brush groups are arranged side by side with adjacent brush groups at a predetermined interval Go. That is, this spacing is arranged in a larger dimension than the spacing G between the individual brushes in the brush group. The reason for this spacing in practical use will be explained later, but for example, if the distance between each adjacent sakaki in the brush group is 35, it is sufficient to set the distance to about 6. Experimental results showed that the larger the distance, the more advantageous the result, but the larger the distance, the less the number of brushes to be installed in parallel, which is undesirable and the most efficient dimension is the distance of one brush. It seems better to keep it. In practical use, the brush group is particularly preferably formed as follows.

FIGS. 4 and 5 show a comparison between the conventional brushes and the brushes according to the present invention, and FIG. 4 shows the required number of brushes 3 for a slip ring 2 of a certain size This is a subordinate structure in which the following are arranged in sequence.

As can be seen from this, the individual brush spacings ○2 are all approximately constant. On the other hand, FIG. 5 shows an embodiment of the present invention, in which the size of the slip ring 2 and the number of brushes 3 are the same as in FIG. The brushes are divided into a predetermined number of brush groups 3a, 3b..., and the adjacent spacing G3 between the individual brushes 3 in the brush group is reduced, and the above-mentioned brush spacing ○2 4th between the adjacent brush groups 3a, 3b... Larger spacing than shown. It is done so that it can be done. In the figure, there is a space G below the slip ring 2 where no brushes are placed, but since this space is below the rotating shaft, it is difficult to inspect or replace the brushes. (referred to as space) is usually not equipped with a brush. Next, we will discuss the function of the current collector layer, which is arranged in parallel for each Sakaki group and has a special brush spacing.

FIGS. 6 and 7 show the relationship between the brush and the slip ring in a developed manner, with FIG. 6 showing the general case and FIG. 7 showing the case of the present invention.

The solid line arrow R in the figure indicates the rotation direction of the slip ring 2,
A solid arrow Z indicates the turbulent flow of gas around the slip ring due to rotation of the slip ring and the flow state of brush abrasion powder.
First, in FIG. 6, when the slip ring 2 rotates in the direction of the arrow, the gas around the slip ring idly rotates between the brushes 3 as shown by the solid line arrow Z.
This idle rotation is performed at a faster speed as the distance between adjacent brushes becomes smaller. In this case, a part of the wear powder of the brush also rotates idly like this gas, and a part of the wear powder escapes from between the brushes to the non-sliding side of the sliding part, but most of it flows into the sliding surface of the next brush.In other words, even if there is a space between the brushes, the idle rotation of the gas due to the rotation of the slip ring 2 creates an idle pressure layer between the brushes. This means that the discharged abrasion powder will rush into the next brush. It is said that this abrasion powder regularly enters the next brush, increasing the brush vibration and resistance heat loss mentioned above. Of course, in this case, it would be possible to blow a jet of gas (indicated by the S arrow) between the brushes from the outside (for example, from a cooling fan) to break this idling action, but it is possible to The closer the brushes are to each other, the more difficult it is to spray cooling gas strongly between each brush, and the cooling fan (11 in Figure 1) installed to cool the concentrated area cannot avoid this gas idling. It is difficult to destroy the effect.
Brush abrasion powder, dust, and gas therefore circulate around the sliding part along its surface in all directions. The running of this abrasion powder on the cat moving surface causes current conduction resistance in the shield part, and also causes the brush to become energized.
It also causes vibration in the pressing direction. This is one of the reasons why the conduction current cannot be improved even if the current collector layer for large currents strengthens the cooling. This problem is solved by the current collector layer of the present invention having a plurality of brush groups, as shown in FIG. It is.

In other words, in the case of FIG. 6, where the gas and powder idling between the individual brushes is no different from the conventional one, on the contrary, the distance 03 between the individual brushes 3 is 4.
・As a result, the idling speed increases, and warm gas and powder tend to rush into the brush sliding surface one after another. However, there is a space Go between the brush groups that is larger than between the individual brushes, and the idling suddenly becomes weak in this part. Therefore, in this part, the idling is easily destroyed by the movement of the external cooling gas S, and in this part, the idling is easily destroyed. The warm gas and powder that have been advancing up to now become easier to be released to the outside (in the direction of the anti-sliding side of the Arashi U-ko). In other words, the central part of the brush group has the same or better effect than before, but the stiffeners at the ends of the brush group (the side facing the rotational direction of the slip ring) are affected by the warm gas from the previous brush. There is less intrusion of particles and powder, and overall, the current carrying capacity can be improved. FIG. 8 shows the results of these experiments, and compares the conventional current collector layer and the current collector layer of the present invention from a temperature standpoint.

It will be seen that the current collector layer y-curve of the present invention is 4-5% lower overall than the conventional current collector layer x-curve.
In this case, the improvement is 4 to 5%, but as mentioned above, this type of gas-cooled large-capacity rotating electric machine has reached its limit in terms of cooling and the size of the slip ring, so it is impossible to reduce the temperature by this much. It is very difficult to have expectations. FIG. 9 shows the vibration measurement results for the applied current of the brush. As is clear from the figure, the current collector system (p curve) of the present invention is better than the conventional collector in terms of brush vibration. It will be seen that it is superior to the electric calendar (Q curve).

As explained above, the rigidity of a slip ring of a certain size and a current collector layer with a certain number of brushes is divided into a plurality of brush groups in the circumferential direction, and the adjacent intervals of the brush groups are set to By arranging the current collector layer so that it is larger than the adjacent spacing between the two, it is possible to improve the ability of the current collector layer, which is said to be at its limit with gas cooling, without using any other special means or equipment. be.

In the above explanation, when forming a rigid brush group, a plurality of brushes are simply divided into a plurality of pieces to form a square brush group on a plane, but this does not always have to be done. For example, it goes without saying that the same effect can be obtained even if the brush groups 3a, 3b, . . . are formed in a diamond shape as shown in FIG.

In addition, it is desirable that each Sakaki group has the same number from the viewpoint of overall temperature, but if it is difficult to configure brush groups with the same number of brushes due to the number of brushes, as shown in Fig. 11. As shown in the above, even if the number of brushes in the brush group 3a adjacent to the apricot inspection space G and facing in the rotational direction of the slip ring is slightly larger than the other brush groups, the experimental results show that the relationship between the apricot inspection spaces is Almost similar results were obtained.

As described above, according to the current collector of the present invention, a plurality of brushes are divided into a plurality of brush groups in the circumferential direction, and the adjacent intervals in all directions of the circumference of the hanger group are set within the brush group. The adjacent spacing in the circumferential direction of the individual brushes in the brush group is made larger than the spacing between the adjacent brushes in the circumferential direction, and the spacing between the adjacent brushes in the circumferential direction in the brush group is made smaller than the spacing when the brushes are arranged equally in the circumferential direction. This type of alternating current rotation can eliminate warm gas and brush abrasion powder from the brush contact surface, and is compact and can conduct a sufficiently stable flow of current without using special cooling equipment or other equipment. A gas-cooled current collector layer for electrical machinery is obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing an embodiment of the current collector layer of the present invention, FIGS. 2 and 5 are longitudinal sectional front views showing an embodiment of the current collector layer of the invention, and FIG. 3 is a plan view thereof. It is a diagram. FIG. 4 is a longitudinal sectional front view showing a conventional current collector layer, FIGS. 6 and 7 are side views showing the relationship between the brush and slip ring of the conventional and counterfeit current collectors, respectively, and FIG. 8 9 is a curve diagram showing the relationship between the brush position and temperature, FIG. 9 is a curve diagram showing the relationship between brush vibration and current, and FIG. 10 is a plan view showing another embodiment of the current collector of the present invention. FIG. 11 is a longitudinal sectional front view showing another embodiment. 2...Slip ring, 3
...Brush, 3a, 3b... Sakaki group, 5...
Rotating shaft, 11... Cooling fan, 12...
・Brush holder. A lot of laughs 2 figures a lot of 4 figures a lot of laugh figures 3 figures a lot of S figures a lot of 7 figures a lot of 8 figures Tsutomu? Drawing lo diagram punching - figure

Claims (1)

[Scope of Claims] 1. A slip ring fixed on a rotating shaft via electrical insulation, and a plurality of slip rings slidably pressed on the surface of the slip ring with a predetermined pressing force, and arranged in a circumferential direction. A gas-cooled current collector for an AC rotating electric machine, which includes brushes arranged in parallel, a brush holder that holds the brushes, and a cooling device that cools the sliding portions of the slip ring and the brushes with cooling gas, The plurality of brushes are divided into a plurality of brush groups in the circumferential direction, and the circumferential spacing between the brush groups is made larger than the circumferential spacing between the individual brushes in the brush group, and the brush group 1. A gas-cooled current collector for an AC rotating electrical machine, characterized in that the distance between adjacent brushes in the circumferential direction is smaller than the distance when the brushes are arranged equally in the circumferential direction. 2. The gas-cooled current collector for an AC rotating electric machine according to claim 1, wherein each of the brush groups is formed of the same number of brushes.