JPH0819207A - Shaft grounding device - Google Patents

Abstract

PURPOSE:To efficiently prevent the adhesion of foreign materials such as dust the grounding brushes of a shaft grounding device. CONSTITUTION:Two pieces of grounding brushes 2 of a shaft grounding device are held in the bracket 4 provided in an oil out 7. The grounding brushes 2 are contained in a dustproof cover 15 together with a bracket 4. A rectangular inspection window 16 is opened in the dustproof cover 15 to matched the grounding brushes 2. A window cover 17 is provided in the inspection window 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft grounding device attached to a shaft system of a steam turbine or a generator for use.

[0002]

2. Description of the Related Art It is well known that shaft voltage is generated in the shaft system of steam turbines and generators. The cause is typically an electromagnetic induction voltage generated in the generator due to magnetic imbalance, and an electrostatic voltage caused by rotational friction between the blade and the impeller and steam in the wet steam region on the steam turbine side. These shaft voltages must be effectively grounded and maintained at sufficiently low values to ensure the safety of the equipment.

Generally, in a steam turbine of a steam seal type gland packing, since there is no grounding circuit between the shaft (rotating part) and a stationary part, a bearing and a driving gear part of a governor used in a mechanical hydraulic control type steam turbine. In some cases, electric discharge may occur in a minute gap such as, and electric contact may occur. The electric contact of the bearing portion appears as pitting corrosion, which leads to roughening of the surface of the bearing pressure receiving portion and the surface of the shaft in contact therewith, which significantly impairs its function. In the worst case, the bearing may be burned. In addition, if an electric contact occurs in the drive gear of the governor, the steam control valve that operates based on the detection signal may malfunction and the control of the steam turbine may fail.

FIG. 14 shows an example of a shaft grounding device that has been conventionally used to prevent such electric contact. In FIG. 14, the ground brush 2 made of a copper braid is in contact with the surface of the generator shaft 1, and the back side of the ground brush 2 is pressed by the leaf spring 3 to ensure grounding more securely. Leaf spring 3
The spring constant of is designed based on some experimentally determined criteria. This is because if the spring is strong, the wear is likely to proceed, and if it is too weak, it causes ground contact failure. Therefore, it is necessary to decide to settle in the optimum range.
The ground brush 2 and the leaf spring 3 are fixed to a bracket 4 as a retainer with bolts 5. This racket 4 is fixed to the oil drainer 7 at the rearmost portion on the turbine side with bolts 6.

Usually, considering the importance of such shaft grounding,
Two grounding flanges 2 are attached to the oil drainer 7 with a space between each other to enhance reliability, and one of the grounding flanges 2 can be inspected, repaired or replaced during operation, if necessary. Oil drainer 7 with these two ground flanges 2 attached
Are fixed to the turbine bearing base 9 by bolts 8.
The oil drain 7 is used to prevent the lubricating oil in the turbine bearing base 9 from leaking to the outside.

By the way, as the material of the ground brush 2, a silver brush, a carbon brush or the like is used in addition to the copper braid. However, all of them are easily worn, they are not as maintainable and reliable as copper-based materials, and the contact resistance is as small as that of silver brushes, except when copper-based materials cannot be used due to corrosion problems in geothermal turbines. A copper braided wire brush, which has a capacity as large as a carbon brush, is preferred.

FIG. 15 shows the overall construction of a shaft voltage prevention system using this shaft grounding device. As described above, the ground brush 2 in contact with the surface of the generator shaft 1 is attached to the oil drainer 7 via the bracket 4, and the oil drainer 7 is fixed to the turbine bearing base 9. The turbine bearing base 9 and the turbine casing 11 accommodating the turbine rotor 10 have an integral structure, and these are connected to the ground through a ground wire 12. Turbine rotor 1
A generator shaft 1 driven by 0 is connected to a turbine rotor 10 by a coupling 13.

Since each of these elements is made of a metal material that is a good conductor of electricity, the axial voltage of the generator shaft 1 including the axial voltage transmitted from the turbine rotor 10 is collected through the ground brush 2 and oil. It is escaped to the ground through the cut 7, the turbine casing 11, and the ground wire 12.
The ground wire may be directly connected to the ground brush 2 without passing through the ground wire 12 connecting to the turbine casing 11.

[0009]

However, in the above-mentioned shaft grounding device, mist (sprayed oil) from the oil removing device 7 adjacent to the shaft grounding device, dust in the air, and foreign matter artificially generated in the case of painting work, etc. And the like may enter, and these may adhere to the ground brush 2 to increase the ground resistance, resulting in poor grounding. Further, the grounding brush 2 itself deteriorates due to wear, which may cause grounding failure. Further, the leaf spring 3 is deteriorated, the pressing force is weakened, and the ground resistance increases due to poor contact, which may increase the shaft voltage.

On the other hand, since the grounding brush 2 according to the prior art is pressed against the generator shaft 1 by the leaf spring 3, it is difficult to adjust and contact failure often occurs. Once in such a state, the function of the shaft grounding device is not fulfilled, and as described above, electric contact occurs in the bearing portion and the like. In order to effectively use this shaft grounding device, planned and daily inspection of the shaft grounding device is indispensable, but the burden of inspection work increases accordingly, and it is not always guaranteed that it will be enforced. In many cases, inadequate maintenance has resulted in poor grounding of the shaft, causing damage due to electrical contact.

Therefore, an object of the present invention is to provide a shaft grounding device which effectively prevents foreign matter such as dust from adhering to the grounding brush.

Another object of the present invention is to provide a shaft grounding mount capable of stably pressing the grounding brush against the generator shaft under a constant pressing force.

[0013]

According to a first aspect of the present invention, there is provided a shaft grounding device in which at least one ground brush made of a braid extends from a cage to a surface of a generator shaft. It is characterized in that a protective structure provided with a window is provided.

According to a second aspect of the present invention, there is provided a shaft grounding device in which at least one ground brush composed of a braid extends from the cage to the surface of the generator shaft, and the ground brush is directed toward the generator shaft contact end. The present invention is characterized in that an air-type pressing device having an outlet for blowing air is provided.

Further, the invention according to claim 3 is characterized in that a spring type traction device for pulling the generator shaft contact end side of the ground brush is provided in place of the air type pressing device.

Further, in the invention according to claim 4, an air type or hydraulic type pressing device having an air cylinder or a hydraulic cylinder for pressing the generator shaft contact end side of the ground brush is provided instead of the air type pressing device. It is a feature.

According to a fifth aspect of the present invention, there is provided a brush retainer having three rollers arranged so that the lines connecting the centers of rotation thereof form a triangle, and the rollers of the brush retainer have an endless ground brush. The brush holder is arranged so that one of the three sides of the grounding brush locally contacts the surface of the generator shaft.

Further, the invention according to claim 7 is provided with a brush holder comprising a pair of reels arranged apart from each other, and an auxiliary roller attached to each of these reels, and each reel of the brush holder. , A belt-shaped ground brush is applied to each auxiliary roller, and the brush holder is arranged so that a part of the ground brush between the auxiliary rollers is in contact with the surface of the generator shaft.

Further, the invention according to claim 9 provides a protective structure having an inspection window for accommodating a grounding brush held by a spring type index device, an air cylinder or a hydraulic cylinder, or a brush holder.

The invention according to claim 10 is an air blower having a blower for blowing air toward a ground brush held by a spring type traction device, an air type pressure device or a hydraulic type pressure device, and a brush holder. A device is provided.

[0021]

According to the first aspect of the present invention, a storage type protection means is added to prevent the ground resistance from increasing due to foreign matter such as dust flowing around the shaft grounding device adhering to the ground brush. Further, the invention of claim 2 is configured by adding an air type pressing device which also serves as a foreign matter processing means for the ground brush. That is, the protective structure configured as a storage-type protective means blocks foreign substances that try to enter from the outside by the protective wall and removes them before they adhere to the ground brush.

On the other hand, the air-type pressing device is provided with a blow-out port, for example, a nozzle, which blows air toward the generator contact end having the function of holding the ground brush, and foreign matter flowing into the ground brush is compressed by high-pressure air. Blow it off and also remove it before sticking to the ground brush.

Thus, by effectively removing the foreign matter, the increase in the ground resistance due to the adhesion of the foreign matter can be prevented, and the ground failure can be prevented.

In particular, when the protective structure is used, inspection,
It is not easy to remove the protective structure itself after each maintenance, because it is a heavy load. Therefore, it is desirable that an inspection window used only for the protective structure is provided in advance so that all the work can be performed only by opening and closing the window cover. Further, the protective structure and the air type pressing device (which is also referred to as an air type blowing device in other inventions) can be applied to all other inventions except claims 1 and 2, and particularly The invention of claim 9 adds a protective structure, and the invention of claim 10 makes it possible to obtain the same effect by adding an air blower.

Further, in order to maintain a stable contact between the grounding brush and the generator shaft, the invention of claim 2 is constructed by adding an air-type pressing device having an outlet for blowing air toward the generator shaft contact end. The invention of claim 3 is configured by adding a spring type traction device for pulling the generator shaft contact end side inward to obtain the same effect, and the invention of claim 4 is an air cylinder or hydraulic pressure for pressing the generator shaft contact end side. An air pressure device or a hydraulic pressure device equipped with a cylinder is added.

In this air-type pressing device, the high-pressure air from the outlet can be directly applied to the ground brush to obtain a constant pressing force under an appropriate pressure. Further, the spring-type traction device can pull the ground brush toward the generator shaft side to obtain a constant pressing force under the adjusted spring force.

Further, the pneumatic or hydraulic pressing device can exert a regulated pressing force of the air cylinder or the hydraulic cylinder on the ground brush to obtain a constant pressing force. Since it is under a constant pressing force regardless of which means is used, the contact of the ground brush with the generator shaft can always be kept stable, and it is possible to reliably prevent ground failure. .

The present invention as claimed in claims 5 and 6 is a method of constructing an endless type grounding brush as an alternative to a usual brush piece.
Further, the invention of claims 7 and 8 is also a method of constructing a belt-shaped ground brush instead of the brush piece. The endless type ground brush is a brush holder provided for the present invention.
The belt-shaped ground brush is used by hanging it on a pair of reels of the brush holder and the auxiliary roller. Both ground brushes have the advantage that the tension can be freely changed, and when a part of the ground brush between the two rollers is placed in contact with the surface of the generator shaft, a proper tension is applied thereto. The current collecting performance can be kept optimum by appropriately increasing the tension of the grounding brush, and a good grounding function can be maintained.

[0029]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of the invention according to claim 1. The same reference numerals as those used in the description of the prior art are attached to the shaft grounding device. Two ground brushes 2 of the shaft grounding device are provided as in the prior art, and these ground brushes 2 are housed in the dustproof cover 15 together with the holder thereof. The dustproof cover 15 has a short inspection window 16 that is open to match the two ground brushes 2, and the inspection window 16 is provided with a window cover 17 which will be described in detail later.

The dust cover 15 is provided with an integral flange 18 on the oil drain 7 side, and the dust cover 15 is fixed to the oil drain 7 by a large number of bolts 19 using the flange 18. The dust-proof cover 15 of the present embodiment is configured to cover the upper half of the horizontal in consideration of disassembly and assembly, but of course other shapes may be used.
2 (a) and 2 (b), a window cover 17 provided on the inspection window 16
Shows the details of. As shown in FIG. 2A, the window cover 17 has a larger outer dimension than the inspection window 16, and covers the outside of the inspection window 16 except when the inspection window 16 is open so that dust or the like enters from the outside. Is designed to prevent The window cover 17 is provided with a hinge 17a so that the dust cover 15
When the opening is required for inspection or maintenance, the window cover 17 can be rotated by the hinge 17a to expose the inspection window 16 as shown in FIG. 2 (b). In the figure, reference numeral 17b is a handle. Next, the operation of the above configuration will be described.

The dustproof cover 15 housing the two shaft grounding devices is not limited to when the steam turbine is in operation and also when the steam turbine is not operating. To prevent sticking to. This dust cover 15
Is not only effective as a protection means against the intrusion of dust and foreign matter from the outside, but especially the mist of lubricating oil generated inside adheres to the inner surface of the dustproof cover 15 having a large area, so that The amount of adhesion can be reduced. The ground brush 2 needs to be inspected and maintained. The window cover 17 is opened, the ground brush 2 is observed through the inspection window 16, and any mist lump is removed. This can be performed relatively easily without the intrusion of dust or the like.

As described above, in this embodiment, it is possible to reliably prevent foreign matter such as dust from adhering to the ground brush 2, and the inspection window 16 can be used during inspection and maintenance.
It is not disturbed by the dust cover 15.

FIG. 3 shows an embodiment of the invention according to claim 2. Two ground brushes 2 of the shaft grounding device of this embodiment are also provided as in the prior art. This shaft grounding device is different from the prior art in that it is constituted by a brush retainer 20 instead of the leaf spring 3, and that an air type pressing device 21 is further added. The brush retainer 20 retains the ground brush 2 with a force weaker than that of the leaf spring 3. The air-type pressing device 21 can use various means,
In this embodiment, it is configured as follows. That is, a nozzle 23 is provided near the ground brush 2 as a blowout port supported by a stopper 22 extending from the oil drainer 7. The tip of the nozzle 23 is directed toward the generator shaft contact end of the ground brush 2. There is. Further, the nozzle 23 is connected to an air pipe 24 which is connected to an air source described later.

FIG. 4 shows details of the air system used in the air-type pressing device 21. The other end of the air pipe 24 connected to the nozzle 23 is connected to the air source 25. An electromagnetic valve 26 is interposed in the path of the air pipe 24, and the electromagnetic valve 26 is opened / closed by an opening / closing signal from a switch 27. FIG. 4 shows an air type pressing device 21.
A shaft voltage prevention system is also shown, but this is shown in FIG.
Is the same as that shown in. Although only one system is shown as the air pipe 24 for simplification in this figure, it is divided into two systems near the ground brush 2 in accordance with the nozzle 23 of FIG.

Next, the operation of the above configuration will be described.

The air supplied to the nozzle 23 through the air pipe 24 is blown to the generator shaft contact end of the ground brush 2, and the pressure causes the ground brush 2 to be pressed against the surface of the generator shaft 1. The air pressure device 21 maintains an appropriate air pressure to maintain a good grounding function. The brush retainer 20 does not have a function of applying a pressing force to the ground brush 2 and has a function of reinforcing the structurally weak copper braided wire so as not to deform it.

Another function of the air-type pressing device 21 is as a blowing device. Even if foreign matter such as floating dust around the surface of the ground brush 2 flows, the foreign matter is blown off by the high pressure air before the adhesion and does not adhere to the ground brush 2. It is possible to reliably blow off relatively light foreign matter such as dust before adhering to the foreign matter, and the trouble of cleaning the ground brush 2 or the like becomes almost unnecessary. Further, even if the mist of the lubricating oil flows around the grounding brush 2, it also blows off before it adheres, so that the amount of adhesion can be drastically reduced. Part of dust and mist may adhere with long-term use, but the amount is small and it does not take time to remove.

In this embodiment, air is supplied and stopped by opening / closing the solenoid valve 26 shown in FIG. The actuation signal causes air to flow to the ground brush 2 when the contacts of the stitch 27 are closed.

As described above, in this embodiment, since the ground brush 2 is pressed against the generator shaft 1 by the air pressure, a constant pressing force can be maintained, and it can be used like a plate spring. It is possible to prevent the deterioration of the grounding function over time without causing deterioration in the inside.

Further, since dust and mist are blown off by the air before they adhere to the ground brush 2, there is no concern that the ground resistance will increase due to the adhesion of foreign matter and that grounding failure will occur during use, and it will be stable for a long period of time. It becomes possible to maintain the grounding function.

Further, the air blow-out range can be expanded to spread the pressing force over a wide range of the ground brush 2, which eliminates the need for high precision in adjustment as in the case of using a leaf spring, and maintenance Becomes extremely easy.

Further, another embodiment will be described.

FIG. 5 shows an embodiment of the invention according to claim 3. The shaft grounding device of this embodiment is also provided with two grounding brushes, but this grounding brush, including the cage, is significantly different in shape from the conventional one. A grounding brush 30 having one end fixed by a bracket 31 as a retainer provided on the oil drainer 7 via a bolt 6 has the other end connected to a traction device 32. The traction device 32 of the present embodiment is composed of a coil spring 33, a connecting piece 34 connecting the coil spring 33 and the ground brush 30, and a column 35 which is embedded in the oil drainer 7 and holds the other end of the coil spring 33. ing. As shown in the figure, the two ground brushes 30 are arranged symmetrically about the generator axis.

Next, the operation of the above configuration will be described. The ground brush 30 is attracted inward by the pulling end of the pulling device 32 including the coil spring 33 added to the fixed end by the bracket 32. As a result, the coil spring 34
The generator shaft contacting end of the grounding brush 30 close to is strongly pressed against the surface of the generator shaft 1. Although the leaf spring 3 extending from the fixed end side of the conventional grounding brush 2 is deteriorated once, the pressing force is weakened at the contact end on the opposite side, which causes poor grounding, so that inspection and maintenance have always been indispensable. In this embodiment, the coil spring 3 is provided together with the fixed end.
The grounding brush 30 can be surely pressed against the generator shaft 1 by the towed end by 3, and the grounding function can be maintained for a long time. As described above, in this embodiment, a reliable pressing force can be maintained for a long period of time, and a stable grounding function can be maintained.

6 and 7 show an embodiment of the invention according to claim 4. In FIG. 6, two ground brushes 2 of the shaft grounding device according to the present embodiment are also provided as in the prior art. Among the means used in the shaft grounding device, what is different from the prior art is that the brush retainer 40 is used in place of the leaf spring 3,
Further, an air type pressing device 41 is added to the shaft grounding device. The brush presser 40 does not exert a pressing force on the ground brush 2 but presses the ground brush 2 with a weak force.

The air-type pressing device 41 is constructed as follows. That is, the air cylinder 43 supported by the support member 42 extending from the oil drainer 7 is provided in accordance with the tip of the ground brush 2, and the pusher 44 at the tip of the air cylinder 43 contacts the tip of the ground brush 2. It is touched. Further, an air pipe 45 for sending air is connected to the air cylinder 43. Further, the air cylinder 43 has a spring 43a built therein. The two shaft grounding devices are arranged approximately 90 ° apart in the circumferential direction.

FIG. 7 shows the details of the air system used for the pressing device 41.

Air piping 45 connected to the air cylinder 43
The other end of is connected to an air source 46, and an electromagnetic valve 47 is interposed in this path. The solenoid valve 47 is controlled by a signal from the switch 48. The air pipe 4
5, only one system is shown, but it is configured by branching from the middle in accordance with the two air cylinders 43 in FIG.

Next, the operation of the above configuration will be described. When the air supplied through the air pipe 45 fills the air cylinder 43, the pusher 44 operates to press the generator shaft contact end of the ground brush 2 against the surface of the generator shaft 1. On the other hand, when the air supply is cut off, the pusher 44 operates in the opposite direction by the force of the spring 32a, and the ground brush 2
Move away from

In this pressing device 41, the air pressure is properly maintained and a good grounding function is maintained. If the push bar 44 keeps pressing the ground brush 2 hard, the ground brush 2 will wear faster, so it is desirable to add a monitoring function to maintain an appropriate pressure. The brush retainer 40 does not have a function of applying a pressing force, and has a function of reinforcing the copper braided wire so as not to lose its shape.

Similar to the above-described embodiment (see FIG. 4), air is supplied and stopped by opening / closing the solenoid valve 47 shown in FIG.

Thus, in this embodiment, the generator shaft 1
Since the grounding brush 2 is pressed by the air pressure, the pressing force can be kept constant, there is no deterioration like a leaf spring, and the deterioration of the grounding function with time can be prevented. It is possible.

Incidentally, a hydraulic pressing device may be used instead of the air pressing device 41 of the embodiment. in this case,
Air cylinder 4 for hydraulic cylinders, hydraulic piping, hydraulic sources, etc.
2, it replaces with the air piping 45, the air source 46, etc., and is comprised.

FIGS. 8A and 8B show an embodiment of the invention according to claim 5. In FIG. 8A, the grounding brush of the present embodiment is an endless type brush 50 that replaces a normal brush piece.
It consists of. The ground brush 50 is hung on a brush holder 51 provided near the generator shaft 1. The brush holder 51 on which the endless ground brush 50 is hung is a table 52 provided on the oil drainer 7, and three roller shafts 53 embedded on the upper surface of the table 52.
a, 53b, 53c and the roller shafts 53a, 53b,
Three rollers 54 rotatably provided on 53c
a, 54b, 54c. Two brush holders 51 are provided, and are arranged on the upper half side of the oil drainer 7 at the center of the generator shaft and the object, respectively.

The two rollers 54a, 54b, 54
As shown in FIG. 8B, c is arranged so that the lines connecting the centers of rotation of each other form a triangle, and the grounding brush 50 has one of the three sides (the roller 54b and the roller 54 in this figure).
(between c) is locally in contact with the surface of the generator shaft 1 to collect the shaft voltage. In particular, the roller shaft 53a
With regard to the above, in order to adjust the tension of the ground brush 50, its position can be finely adjusted on the upper surface of the table 52.

Next, the operation of the above configuration will be described. Three
The endless grounding brush 50, which is wound around the individual rollers 54a, 54b, 54c with appropriate tension, is pressed against the surface 1 of the generator shaft 1 with a constant pressing force between the two rollers 54b, 54c. The brush holder 51 has a robust structure and can maintain a good grounding function under a stable pressing force for a long period of time. However, wear of the ground brush 50 is unavoidable over time, and therefore, when the continuous action is, for example, one year, the rollers 54 a, 54.
Rotate b and 54c slightly and adjust the brush contact position so that the new surface of the ground brush 50 contacts the generator shaft 1. By appropriately performing this adjustment, an unused surface can be always brought into contact with the generator shaft 1, and a stable grounding function can be obtained.

If the copper braided wire stretches during use, the position of the roller shaft 53a is changed by fine adjustment to further strengthen the ground brush 50.

As described above, in the present embodiment, since the ground brush 50 is constantly applied with a proper tension and pressed against the generator shaft 1, there is no fear of a settling such as a spring, and the grounding function is prevented from deteriorating. You can Further, the grounding brush 50 is an endless type, and by gradually changing the contact position, it is possible to always recover a good current collecting function for maintaining the performance and prevent the grounding function from decreasing.

Furthermore, the endless type grounding brush 50 can be repeatedly used until it makes one revolution, and the brush life can be remarkably extended as compared with a brush piece that is severely discarded.

9A and 9B show an embodiment of the invention according to claim 7. In FIG. 9A, the ground brush of this embodiment uses a long belt-shaped ground brush 60 instead of the endless ground brush of the above embodiment.

The ground brush 60 is hung on the brush holder 61, and two ground brushes 60 are provided as in the prior art. Brush holder 61 over which the ground brush 60 is hung
Are two reel shafts 62a, 62b and two auxiliary roller shafts 63a, 63b provided on the oil drainer 7, and these reel shafts 62a, 62b and auxiliary roller shafts 63a, 63b.
It is composed of two reels 64a, 64b and two auxiliary rollers 65a, 65b that are rotatably provided.

The two brush holders 61 are arranged on the upper half side of the oil drainer 7 symmetrically with the generator shaft center. Further, as shown in FIG. 9B, the two reels 64a and 64b have a portion between the auxiliary rollers 65a and 65b at the generator shaft 1.
Place them apart from each other so that they serve as contact surfaces with.
A part of this contact surface contacts the surface of the generator shaft 1, and the shaft voltage is collected. In the present embodiment, the two reels 64a and 64b are hereinafter referred to as the reel 64a and the reel 64b, respectively. As long as one can replace the other.

Next, the operation of the above configuration will be described. A belt-shaped ground brush 60 extending between the respective auxiliary rollers 65a and 65b keeps an appropriate tension and sends out the reel 6
4a and the take-up reel 64b. When this tension is applied, the ground brush 60 comes into contact with the generator shaft 1 under a constant pressing force. As described above, this embodiment has a structure suitable for obtaining a stable tension as in the above embodiments, and can maintain a good grounding function. If the contacting part is worn away, the current collecting performance will be deteriorated. Therefore, the contacting position should be changed appropriately so that the performance does not change. While rotating the delivery reel 64a in the delivery direction, the take-up reel 64b is simultaneously rotated in the winding direction. In this way, the unused portion can always be brought into contact with the generator shaft 1, and a stable grounding function can be obtained.

As described above, in the present embodiment as well, there is no concern about the occurrence of sag like a spring or the like, and if abrasion occurs, the contact position can be changed immediately to prevent deterioration of the grounding function. . Furthermore, a belt-shaped ground brush 60
Since it is configured as described above, it can be repeatedly used until the last part thereof is used up, and the brush life can be remarkably extended without being discarded as in the conventional brush piece.

Further, another embodiment will be described. The present embodiment is the invention according to claim 9.

Means similar to the dustproof cover 15 shown in FIG. 1 can be equally applied to the shaft grounding device shown in FIGS. 5, 6, 8 and 9. In this embodiment, the ground brush 3
0, 2, 50 and 60 are housed in the dustproof cover 15 together with their retainer, traction device and pressing device. Even if dust or flying objects from the outside flow around the ground brushes 30, 2, 50, 60, the dust-proof cover 15 prevents the dust from entering the inside.
Contamination of the ground brush by these foreign matters is prevented. Functions of the retainer, the traction device, etc. are as described in each embodiment. Illustration of this embodiment including the dustproof cover 15 is omitted. FIG. 10 shows an embodiment according to the invention of claim 10. The traction device 32 is composed of the coil spring 33 shown in FIG. Further, in order to effectively remove foreign matters such as dust flowing around the ground brush 30, an air blow device 21 similar to the air pressing device 21 shown in FIGS. 3 and 4 is provided. The air blown from the nozzle 23 of the air blower 21 blows away foreign substances flowing around the ground brush 30, and removes the foreign matter before adhering to the ground brush 30. The operation of the towing device 32 is as described in the embodiment of FIG.

FIG. 11 shows an embodiment according to the invention of claim 10. In this embodiment, an air blower 21 similar to the air pusher 21 shown in FIGS. 3 and 4 is provided together with the air pusher 41 shown in FIGS. 6 and 7. The purpose of using the air blower 21 is to enhance the effect of preventing foreign matter from adhering to the ground brush 2 as in the above-described embodiment. The operation of the air pressure device 41, which is constructed around the pneumatic cylinder 43, is as described in the embodiments of FIGS. 6 and 7. Needless to say, the air cylinder 43 presses the generator shaft contact end side of the ground brush 2, and the role of the blower device 21 is only to remove foreign matters flowing to the ground brush 2. It is provided on the upstream side of the ground brush 2 in the axial rotation direction.

In the embodiment shown in FIGS. 10 and 11, the pressing force of the ground brushes 30, 2 is ensured without excess or deficiency, and at the same time, foreign matter and the like that adhere to the ground brushes are effectively removed. Therefore, frequent inspection and maintenance are required. It is possible to keep the grounding function stable for a long period of time without doing so.

Further, another embodiment will be described. FIG. 12 also shows an embodiment of the invention according to claim 10. The shaft grounding device of this embodiment is configured by adding an air blowing device 21 similar to the air pressing device 21 shown in FIGS. 3 and 4 to the brush holder 51 shown in FIG. Also in this embodiment, the air blown from the nozzle 23 of the air blower 21 blows away the foreign matter flowing around the endless ground brush 50 and removes it before adhering to the ground brush 50.

FIG. 13 also shows an embodiment of the invention according to claim 10, in which the shaft grounding device is the brush holder 61 shown in FIG. 9 and the pneumatic pressing device 21 shown in FIGS. 3 and 4.
The air blowing device 21 similar to the above is added.
The purpose of using the air blower 21 is to enhance the foreign matter adhesion prevention effect on the ground brush 60, as in the above embodiment.

The functions of the brush holders 51 and 61 in these two embodiments are the same as those described in the respective embodiments, and the function of the air blower 21 which is highly effective in preventing the ground brush from being contaminated. By joining,
It is possible to maintain a stable grounding function for a long period of time without frequent maintenance.

[0072]

As described above, since the invention according to claim 1 is provided with the protective structure for housing the ground brush,
It is possible to reliably prevent foreign substances such as dust floating around the shaft grounding device from being blocked by the protective wall and not entering the protective structure, and adhering these foreign substances to the ground brush.

Further, according to the second aspect of the present invention, since the air-type pressing device having the outlet for blowing the air toward the generator shaft contact end of the ground brush is provided, the generator shaft can be pressed with a constant pressing force. Can be pressed against. Further, it is possible to reliably remove dust and mist before adhering by high pressure air.

Further, since the invention according to claim 3 is provided with the spring type traction device for pulling the generator shaft contacting end side of the ground brush inward, the ground brush can be reliably pressed against the generator shaft.

Further, since the invention according to claim 4 is provided with the pressing device provided with the air cylinder or the hydraulic cylinder for pressing the generator shaft contact end side of the ground brush, the ground brush is applied to the generator shaft with a constant pressing force. It can be pressed.

Furthermore, in the invention according to claim 5, the three rollers of the brush holder are arranged so that the lines connecting the centers of rotation thereof form a triangle, and an endless grounding brush is applied to the rollers to hold the brush. Since the container is arranged so that one side of the grounding brush locally contacts the surface of the generator shaft, the grounding brush can be pressed stably against the generator shaft under appropriate tension.

In the invention according to claim 7, a belt-shaped ground brush is applied to the pair of reels of the brush holder and the auxiliary rollers attached to these reels, and the brush holder is assisted on the surface of the generator shaft. Since the grounding brush between the rollers is arranged so as to partially contact the grounding brush, the grounding brush can be stably pressed against the generator shaft under appropriate tension.

Further, the invention according to claim 9 is claim 3,
In addition to the configurations of 4, 5, and 7, a protective structure for accommodating the grounding brush is provided, so that foreign matter such as floating dust does not enter the protective structure, and these foreign matter adhere to the grounding brush. Can be reliably prevented.

The invention according to claim 10 is claim 3,
In addition to 4, 5, and 7, each is equipped with an air blower equipped with an outlet that blows air toward the ground brush, so it is effective before dust or mist is attached to the ground brush by high-pressure air. Can be excluded.

Therefore, according to the first, second, ninth, and tenth aspects of the present invention, the increase of the grounding resistance due to the adhesion of foreign matter does not occur, and the damage of the turbine bearing portion due to the grounding failure due to the electrolytic corrosion is prevented. be able to. On the other hand, it is possible to simplify inspection and maintenance.

According to the second, third, fourth, fifth and seventh aspects of the present invention, constant and constant contact with the generator shaft is maintained, and damage to turbine components due to electric contact caused by grounding failure can be eliminated. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a shaft grounding device according to the present invention.

FIG. 2 is a perspective view of the dustproof cover shown in FIG.

FIG. 3 is a perspective view showing another embodiment of the present invention.

FIG. 4 is a system diagram showing an air system used in the pressing device shown in FIG.

FIG. 5 is a perspective view showing another embodiment of the present invention.

FIG. 6 is a perspective view showing another embodiment of the present invention.

7 is a system diagram showing an air system used in the pressing device shown in FIG.

FIG. 8 is a perspective view showing another embodiment of the present invention.

FIG. 9 is a perspective view showing another embodiment of the present invention.

FIG. 10 is a perspective view showing another embodiment of the present invention.

FIG. 11 is a perspective view showing another embodiment of the present invention.

FIG. 12 is a perspective view showing another embodiment of the present invention.

FIG. 13 is a perspective view showing another embodiment of the present invention.

FIG. 14 is a perspective view showing an example of a conventional shaft grounding device.

FIG. 15 is a system diagram showing a conventional shaft voltage prevention system.

[Explanation of symbols]

 1 ... Generator shaft 2, 30, 50, 60 ... Ground brush 7 ... Oil drainer 15 ... Dust cover 16 ... Inspection window 23 ... Nozzle 24, 45 ... Air piping 33 ... Coil spring 43 ... Air cylinders 54a, 54b, 54c ... Rollers 64a, 64b ... Reels 65a, 65b ... Auxiliary rollers

Claims (10)

[Claims] 1. A shaft grounding device comprising at least one ground brush made of a braid extending from a cage to the surface of a generator shaft, wherein a protective structure having an inspection window for accommodating the ground brush is provided. A shaft grounding device characterized in that 2. A shaft grounding device comprising at least one ground brush made of a braid extending from a cage to the surface of a generator shaft, and an outlet for blowing air toward the generator shaft contact end of the ground brush. A shaft grounding device comprising an air-type pressing device provided. 3. The shaft grounding device according to claim 2, further comprising a spring-type traction device for drawing the generator shaft contact end side of the grounding brush instead of the air-type pressing device. 4. An air-type or hydraulic pressing device provided with an air cylinder or a hydraulic cylinder that presses the generator shaft contact end side of the ground brush, instead of the air-type pressing device. 2. The shaft grounding device described in 2. 5. A brush holder having three rollers arranged so that lines connecting the centers of rotation of each other form a triangle, and an endless ground brush is applied to the rollers of the brush holder, A shaft grounding device in which a brush holder is arranged on the surface of the generator shaft so that one of the three sides of the grounding brush locally contacts. 6. The shaft grounding device according to claim 5, wherein two brush holders are provided in an upper half side stationary portion symmetrically with the center of the generator shaft. 7. A brush holder comprising a pair of reels spaced apart from each other and an auxiliary roller attached to each of these reels, wherein each reel of the brush holder and each auxiliary roller are provided. A shaft grounding device in which a belt-shaped grounding brush is applied and the brush holder is arranged so that a part of the grounding brush between the auxiliary rollers is in contact with the surface of the generator shaft. 8. The shaft grounding device according to claim 7, wherein two brush holders are provided in the upper half side stationary portion symmetrically with the center of the generator shaft. 9. A protective structure provided with an inspection window for accommodating the ground brush held by the spring type indexing device, the air cylinder or the hydraulic cylinder, or the brush holder. The shaft grounding device according to any one of 3 to 8. 10. A spring-type traction device, an air-type pressure device or a hydraulic-type pressure device, and an air-type blow device provided with an outlet for blowing air toward the ground brush held by the brush holder. The shaft grounding device according to any one of claims 3 to 8, wherein the shaft grounding device is provided.