Slip ring transmission system

Abstract

The invention relates to a slip ring transmission system (S) comprising a housing (25) and a slip ring transmitter (1) having at least one slip ring (2) that can be rotated in the housing (25), and at least one contact carrier (3) which carries at least one contact means (10) which presses against the dynamically moving slip ring (2), wherein at least one slip contact region (6) between the contact means (10) and the dynamically moving slip ring (2) is embedded in an insulating fluid, wherein the contact means (10) has a plurality of contact lamellae (12) that are subjected to a pressing force, and wherein the insulating fluid in the slip contact region (6) between the contact lamellae (12) and the slip ring (2) is interrupted both when the slip ring is stationary and when it is dynamically moving.

Description

[0001] Slip ring transformer system

[0002] The invention relates to a slip ring transmission system with the features of patent claim 1.

[0003] Slip-ring systems are used to transmit power or data. At higher voltages above 35 kV and with air insulation, the structural complexity of slip-ring systems increases considerably, because the insulation distance between live parts required to ensure partial discharge-free operation inevitably increases. This significantly increases the size and weight of slip-ring systems. However, size plays a crucial role, particularly in explosion-protected areas. It should be as small as possible. The objective is to develop a slip-ring system that can transmit voltages above 35 kV without excessively increasing the size of the slip-ring system, yet is virtually partial discharge-free under static and dynamic loads.

[0004] This object is achieved in a slip ring transmission system having the features of patent claim 1.

[0005] The subclaims relate to advantageous developments of the invention.

[0006] The invention relates to a slip ring transmission system comprising a housing and at least one slip ring rotatable within the housing, as well as at least one contact carrier carrying at least one contact means that presses against the dynamically moving slip ring. The term "dynamic" means that it is not a static, i.e., rigid system, but rather that movement always occurs between the slip ring and the contact means.

[0007] At least one sliding contact area between the contact element and the dynamically moving slip ring is embedded in an insulating fluid. The contact element comprises several contact segments subject to a contact pressure. The insulating fluid surrounding the current-carrying parts must not act as an insulation between the sliding contact and the contact segments. Therefore, the insulating fluid is interrupted in the sliding contact area between the contact segments and the slip ring in a dynamically moving slip ring.

[0008] In particular, the sliding contact area, i.e., the sliding track on the slip ring, is gold- or silver-plated. These materials possess high electrical conductivity, are corrosion-resistant, and always ensure the best contact and thus the lowest contact resistance. To ensure a sufficient contact area between the slip ring and the contact medium, several contact lamellas are provided, which are subject to a defined contact force. The contact force is so great that the contact lamellas are always in contact with the slip ring. The surrounding insulating fluid is not located in the contact area; it merely surrounds it.The insulating fluid, which is preferably a mineral transformer oil or a synthetic ester fluid, has a higher dielectric strength than air, which means that the distances between current-carrying and non-current-carrying parts, especially to the housing, can be significantly reduced. This allows the housing to be smaller. The contact system is practically free of partial discharges. In both static and dynamic tests at a current of 400 A AC under transformer oil, partial discharges of < 10 pC were measured, although the background noise level is already 1 pC. The slip ring assembly is preferably completely immersed in the insulating fluid so that the air gaps between current-carrying and non-current-carrying parts are filled with insulating fluid. In this sense, the housing of the slip ring assembly system is completely filled with the insulating fluid.

[0009] The terms "transformer oil" or "insulating oil" refer to highly refined mineral oils or low-viscosity silicone oils that are stable at high temperatures. Synthetic organic esters can be used as an alternative to conventional mineral oil. These can be saturated pentaerythritol tetrafatty acid esters. The ester fluid is non-toxic, readily biodegradable, and classified as non-water pollutant.

[0010] To maximize the contact area, it is preferably provided that the contact means are in contact with the slip ring on a top and bottom side of the slip ring. For this purpose, the slip ring has sliding tracks on the top and bottom. The contact means are preferably arranged on a common contact carrier that surrounds an edge of the slip ring. The contact carrier can be configured in a fork shape for this purpose. It can be two mirror-symmetrical components, each forming an upper and a lower fork section and connected to each other via a common shaft at the edge of the slip ring.

[0011] In an advantageous development, the contact elements on the top and bottom are arranged offset on the contact carrier in the radial direction of the slip ring. Should a section of this sliding track become worn, the fork-shaped contact carrier can be rotated 180° so that the unused radially adjacent sections of the sliding tracks on the top and bottom come into contact with the contact element. This doubles the service life of the slip ring assembly without great effort.

[0012] The contact carrier is typically made of aluminum. The number of contact segments on the contact carrier is preferably relatively high to provide a sufficiently large contact surface, allowing the contact forces per segment to be reduced, thus reducing wear and increasing maintenance intervals and service life. In particular, several contact segments can be arranged distributed around the circumference of the slip ring.

[0013] In an advantageous development, several contact blades are combined and arranged spring-loaded on a common blade carrier. The blade carrier can be connected as such to the contact carrier. This allows many blades to be mounted simultaneously and easily replaced as a set for maintenance or repair purposes. The blade carrier with the contact blades can be provided as strip material. The strip material can be cut to the desired length.

[0014] In a further development of the invention, it is provided that toroids are positioned in the housing to homogenize the electric field. The toroids are arranged adjacent to the slip ring and coaxially to the slip ring in the region of at least one contact carrier. The toroids are made of an electrically conductive material. Although the toroids require a certain amount of installation space, the homogenized field can reduce the distance between current-carrying components and the housing. The toroids serve to reduce the axial and radial dimensions of the housing of the slip ring transmitter. Preferably, several of the toroids are arranged at an axial distance on both sides of a slip ring. At least one toroid should be arranged on an upper side and one on the lower side. The toroids can be mechanically connected to the slip ring. The toroids reduce and homogenize the electric field strength.Due to their shape, they prevent partial discharges on the live components. Additional toroids with earth potential can be provided in the housing at a distance from the toroids on the slip ring, whereby the overall height can be reduced even further. The overall height can be reduced in particular if two toroids are arranged on the top and bottom of a slip ring, with the toroids arranged concentrically in pairs. The radially inner toroids are preferably the same size, as are the radially outer toroids. The radially inner and outer toroids preferably have the same cross-sectional area. For example, four toroids can be arranged in a square, with the fork-shaped contact carrier arranged approximately in the middle of the square. The slip ring should be enclosed by the toroids. The volume range in which the highest field strength concentrations occur, i.e.in the area of ​​the contact carrier and in the area of ​​the outer edge of the slip ring, which is closest to the housing, is completely homogenized by four toroidal toroids arranged in a square.

[0015] The objective of creating a slip ring transmission system for the transmission of high voltages that is as compact as possible is achieved in particular when at least one toroid and in particular all toroids are arranged in the insulating liquid.

[0016] It is advantageous if the voltage-carrying components, i.e. the slip ring and / or the contact carrier, are held by insulators which are not provided with metallic threaded bolts or receptacles for fastening to adjacent components, but have at least one threaded rod made of glass fiber reinforced plastic (GRP) cast into the insulator for fastening to adjacent components. The insulator is preferably made of an epoxy resin that is free of air pockets. The epoxy resin is cast around the at least one threaded rod. In this way, an insulator can be created from whose opposite ends a threaded rod made of an insulating material protrudes, wherein this threaded rod is used to fasten the slip ring and / or the contact carrier to the insulator(s), or the insulator to the housing of the slip ring transmission system.The invention achieves the objective of providing a slip ring assembly system suitable for use in medium and high voltage applications, while reducing the size of the housing. The slip ring assembly has multiple segments that do not float even during dynamic movement of the slip ring assembly and are always subjected to sufficient contact pressure so that no arcs are generated between the segments and the slip ring. The insulating fluid enables compact and smaller slip ring bodies to be used even at higher voltages. This allows for the use of smaller housings, which is particularly advantageous in explosion-proof areas. The insulation distances within the housing or adjacent to the slip ring assembly are significantly shorter than with slip ring assemblies in air. Additional toroids for homogenizing the electric field further contribute to the reduction in size.

[0017] The invention is explained in more detail below with reference to exemplary embodiments illustrated in schematic drawings. They show:

[0018] Figure 1 is a perspective view of a contact carrier on a slip ring;

[0019] Figure 2 shows the contact carrier of Figure 1 in a side view;

[0020] Figure 3 shows the contact carrier of Figure 1 in a perspective obliquely from below;

[0021] Figure 4 shows the contact carrier of Figure 1 in a perspective obliquely from above;

[0022] Figure 5 shows a slat carrier in a perspective view;

[0023] Figure 6 shows a slip ring in a perspective view;

[0024] Figure 7 is a representation of the electric field in a sectional plane through the slip ring of Figure 6;

[0025] Figure 8 shows an insulator in a side view and

[0026] Figure 9 shows the insulator of Figure 8 in longitudinal section. Figure 1 shows a section of a slip-ring transmission system S with a purely schematically indicated housing 25 in which a slip-ring transmission 1 is located. Neither the shape, the position, nor the distance of the illustrated wall section of the housing 25 from the slip-ring transmission 1 are to scale in the figures, but are purely schematic.

[0027] The essential components of the slip ring assembly 1 are a slip ring 2 and a contact carrier 3, which is fork-shaped and engages over an upper side 4 of the slip ring 2 as well as under a lower side 5 of the slip ring 2. The area overlapped on the upper and lower sides is referred to as the sliding contact area 6.

[0028] The contact carrier 3 consists of an upper and a lower half 7, 8, with both halves being essentially identically configured. The two halves project beyond an edge 9 of the slip ring 2 and are radially connected to one another at the edge to form a common current-carrying shaft. They are screwed together. Figure 2 shows the sectional view and the detailed structure. The contact carrier 3 carries, in its upper half 7 and its lower half 8, a contact means 10 comprising a plurality of contact lamellae 12, as can be seen in Figures 3 to 5. Figure 5 shows a lamella carrier 11 with a plurality of identically configured lamellae 12 with an essentially rectangular cross-section. The lamella carrier 11 with the contact lamellae is referred to collectively as the contact means and is fastened once to the upper part 7 of the contact carrier 3 and once to the lower part 8, as can be seen in Figures 3 and 4.The respective contact elements 10, 11 thus lie opposite one another in the axial direction, but are offset from one another in the radial direction of the slip ring 4, so that they each come into contact with different radial areas of the sliding contact area 6. When the contact carrier 3 or the slip ring 4 is turned, the adjacent areas of the sliding contact area 6 can come into contact with the lamellae 12. This can reduce local wear on the slip ring 4 or increase its service life before the surfaces reach their wear limit. The slip ring is, in particular, provided with a silver or gold coating. The contact carrier is, in particular, made of brass. The housing 25 is filled with an insulating fluid to such an extent that the air gaps between current-carrying components and non-current-carrying components are filled with the insulating fluid.The insulating fluid is a mineral transformer oil or a synthetic ester fluid. The components shown in Figures 1 to 5 are completely immersed in the insulating fluid. This allows for reduced structural clearances between current-carrying components, particularly to the grounded housing.

[0029] A further measure according to the invention for reducing the size is explained with reference to Figures 6 and 7. Figure 6 shows a slip ring 2 with dimensions that differ from Figures 1 to 5. However, the same reference numerals are retained for functionally identical components. Figure 6 also shows a contact carrier 3. Further contact carriers 3 can be arranged distributed around the circumference. To homogenize the electric field, toroids 13-16 made of an electrically conductive material are arranged adjacent to and coaxial with the slip ring 2 in the area of ​​the contact carrier 3. In particular, there are four toroids 13-16 that are arranged in a square as shown in Figure 7, with the contact carrier 3 and the edge 9 of the slip ring 4 being arranged in the center of the square. The toroids 13-16 are arranged in pairs.Two concentric toroids 13, 14 are located on top and axially offset from two further toroids 15, 16 of the same size adjacent to the underside of the slip ring 4. The radially outer toroids 13, 15 have a diameter that is larger than the diameter of the slip ring 2. The two other, radially inner toroids 14, 16 have a diameter that is smaller than the diameter of the slip ring 2.

[0030] Figure 7 describes a single-phase design of a slip ring assembly; in a three-phase design, the three identically constructed phases are arranged vertically stacked. Figure 7 illustrates that the toroids 13-16 homogenize the electric field that builds up around the current-carrying components. In addition, as shown in Figure 7, two further grounded toroids 17, 18 are arranged underneath the live toroids 13-16, and in the same way, two further grounded toroids 19, 20 are arranged on top of the slip ring 2. These toroids 17-20 are at ground potential. They also homogenize the electric field. All toroids are located within the insulating fluid, so that the overall height of the slip ring assembly can be significantly reduced in the axial and radial directions.

[0031] Figure 7 further shows an insulator 21, which is illustrated in Figure 8 in side view and in Figure 9 in longitudinal section. The special feature of this insulator is that it contains no metallic components. The insulator 21 has a base body 22 made of cast epoxy resin, which is free of air inclusions. Threaded rods 23, 24 made of glass fiber reinforced plastic (GRP) were cast into the insulator 21. By avoiding metallic components, this insulator 21 has particularly advantageous properties for use in the slip ring assemblies according to the invention, which are intended to have a particularly compact design and are intended to be used in particular in explosion-proof areas or offshore wind turbines.

[0032] Reference symbol:

[0033] 1 - Slip ring assembly

[0034] 2 - Slip ring

[0035] 3 - Contact carrier

[0036] 4 - Top of 2

[0037] 5 - Bottom of 2

[0038] 6 - Sliding contact area

[0039] 7 - upper part of 3

[0040] 8 - lower part of 3

[0041] 9 - Edge of 2

[0042] 10 - Contact agent

[0043] 11 - Slat carrier

[0044] 12 - Contact lamella

[0045] 13 - voltage-carrying toroid

[0046] 14 - voltage-carrying toroid

[0047] 15 - voltage-carrying toroid

[0048] 16 - voltage-carrying toroid

[0049] 17 - grounded toroid

[0050] 18 - grounded toroid

[0051] 19 - grounded toroid

[0052] 20 - grounded toroid

[0053] 21 - Insulator

[0054] 22 - Base body

[0055] 23 - Threaded rod

[0056] 24 - Threaded rod

[0057] 25 - Housing

[0058] S - Slip ring transmission system

Claims

Patent claims 1. Slip ring transmitter system (S) with a slip ring transmitter (1) arranged in a housing (25) with at least one rotatable slip ring (2), and with at least one contact carrier (3) which carries at least one contact means (10) which presses against the dynamically moving slip ring (2), characterized in that at least one sliding contact area (6) between the contact means (10) and the dynamically moving slip ring (2) is embedded in an insulating liquid, wherein the contact means (10) has a plurality of contact lamellae (12) which are subject to a contact force and wherein the insulating liquid in the sliding contact area (6) of the contact lamellae (12) with the slip ring (2) is interrupted both when the slip ring (2) is stationary and when it is dynamically moving.

2. Slip ring transmission system (S) according to claim 1, characterized in that the insulating liquid is a mineral transformer oil or a synthetic ester liquid.

3. Slip ring transmission system (S) according to claim 1 or 2, characterized in that the contact means (10) on an upper side (4) and a lower side (5) of the slip ring (2) are in contact with the slip ring (2), wherein the contact means (10) are arranged on a common contact carrier (3) which encompasses an edge (9) of the slip ring (2).

4. Slip ring transmission system (S) according to claim 2, characterized in that the contact means (10) on the upper side (4) and the lower side (5) are arranged offset from one another on the contact carrier (3) in the radial direction of the slip ring (2).

5. Slip ring transmission system (S) according to one of claims 1 to 4, characterized in that several contact lamellae (12) are resiliently arranged on a common lamella carrier (11).

6. Slip ring transmitter system (S) according to claims 1 to 5, characterized in that for homogenizing the electric field, at least one voltage-carrying toroid (13-16) made of an electrically conductive material is arranged adjacent to and coaxial with the slip ring (2) in the region of the at least one contact carrier (3).

7. Slip ring transmission system (S) according to claim 6, characterized in that several of the toroids (13-16) are arranged at an axial distance on both sides of a slip ring (2).

8. Slip ring transmission system (S) according to claim 6 or 7, characterized in that two toroids (13-16) are arranged on either side of a slip ring (2), the control rings (13-16) being arranged concentrically.

9. Slip ring transmission system (S) according to one of claims 6 to 8, characterized in that the at least one toroid (13-16) is arranged in the insulating liquid.

10. Slip ring transmission system (S) according to one of claims 1 to 9, characterized in that the slip ring (2) and / or the contact carrier (3) is held by insulators (21) which have a threaded rod (23, 24) made of GRP cast into the insulator (21) for fastening to adjacent components.

11. Slip ring transmission system (S) according to claim 10, characterized in that the insulator (21) consists of an epoxy resin which is free of air inclusions.

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