Slip ring transmitter system

Abstract

Slip ring transmitter system S with a housing 25 and with a slip ring transmitter 1 with at least one slip ring 2 rotatable in the housing 25, and with at least one contact carrier 3, which carries at least one contact means which presses against the dynamically moving slip ring 2, wherein the slip ring 2 is held by at least one insulator 21 and / or the contact carrier 3 is held by at least one insulator 21, wherein the insulator 21 has at least one threaded rod 23, 34 made of a glass fiber reinforced plastic (GFRP) cast into the base body 22 for fastening to adjacent components.

Description

[0001] The invention relates to a slip ring transmission system with the features of claim 1.

[0002] Slip ring systems are used to transmit power or data. At higher voltages above 35 kV and with air insulation, the structural complexity of the slip ring system housings increases considerably because the insulation distance required to prevent partial discharge between the live parts of the contact system and the grounded housing inevitably becomes larger. This results in a significant increase in the size and weight of slip ring systems. The size of slip ring systems plays a particularly important role in explosion-proof areas and should be as small as possible. Examples include explosion-proof areas for FPSO (Floating Production Storage and Offloading) vessels or in offshore wind turbines.

[0003] DE 18 54 488 U relates to a slip ring transmission system with slip ring bodies in which insulating bodies are arranged offset from each other in such a way that, while maintaining the same creepage distances, the air gap between slip rings can be reduced.

[0004] DE 101 06 119 A1 discloses a current transmission arrangement for electrical machines, comprising a shaft with electrically conductive sliding elements extending from and coaxially surrounding it, and carbon brushes supported on these, wherein different electrical phases are connected to current paths leading via windings of the electrical machine via electrically insulated sliding elements. It is proposed that the sliding elements consist of carbon material or are disc elements containing carbon material.

[0005] DE 101 61 740 A1 discloses a slip ring transmitter that can be manufactured and operated more economically in coal-on-coal applications, even with a smaller diameter. It is proposed to embed a circumferentially closed inner ring made of a non-ferrous metal, in particular brass, in an insulating compound as part of a rotor. The insulating compound can be, for example, epoxy resin. The inner ring is electrically connected to the rotor via an electrical terminal and from there to a cable gland at the end face.

[0006] German patent DE 25 10 578 A1 describes a slip ring arrangement in which the slip rings are mounted in a sliding fit onto an insulating layer surrounding a bushing, and the slip rings are clamped axially to the bushing by means of releasable retaining devices. This allows the slip rings to be individually removed from the arrangement and simplifies disassembly.

[0007] The task is to demonstrate a slip ring transmission system that can transmit higher voltages greater than 35kV in the medium voltage range (1 kV to 52 kV) without the size of the slip ring transmission system increasing too much and yet is almost free of partial discharge under static and dynamic loads.

[0008] This problem is solved in a slip ring transmission system with the features of claim 1.

[0009] The dependent claims relate to advantageous further developments of the invention.

[0010] The invention relates to a slip ring transmission system comprising a housing and at least one rotatable slip ring within the housing, as well as at least one contact carrier which carries at least one contact element that presses against the dynamically moving slip ring. The term "dynamic" means that it is not a static, i.e., rigid, system, but that movement always occurs between the slip ring and the contact element.

[0011] The voltage-carrying components of the slip ring transmission system, i.e., the slip ring, are held by at least one insulator and / or the contact carrier is held by at least one insulator. For attachment to adjacent components, the insulator has at least one threaded rod made of glass fiber reinforced plastic (GFRP) cast into a base body. The insulator therefore has no metallic components. The base body preferably consists of an epoxy resin. The epoxy resin is free of air inclusions.

[0012] The threaded rod preferably has the same shape inside and outside the base body. The thread shape on the outside of the threaded rod is securely retained during casting with the base body material. The thread of the threaded rod preferably continues identically outside the base body. This design of the threaded rod is the simplest to manufacture.

[0013] As an alternative or supplement to the thread, anchoring elements can be formed on the threaded rod, such as projections or recesses that deviate from the thread shape, in order to improve the positive locking connection between the material of the base body and the threaded rod, i.e. to improve the pull-out resistance of the threaded rod in the longitudinal direction and / or the resistance to rotation.

[0014] The insulating bodies preferably have a profiled surface to increase the creepage distance. They are preferably long-rod insulators. The ends of the base body are thus positioned at a relatively large distance from each other. The creepage distance is correspondingly long. The threaded rods are preferably located along the central longitudinal axis of the base body. They are spaced apart so that the core of the base body, i.e., the area between the inner ends of the threaded rods, is formed exclusively by the epoxy resin. Specifically, the threaded rods are used to attach the slip ring and / or the contact carrier to the insulator(s), or to attach the insulator to the housing of the slip ring transmitter system.

[0015] Such insulators are particularly well-suited for the desired compact design of the slip ring transmitter system. For the slip ring transmitter system, it is advantageous if 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 has several contact lamellae under pressure. The insulating fluid surrounding the current-carrying parts must not act as an insulator between the sliding contact and the contact lamellae. Therefore, the insulating fluid is interrupted in the sliding contact area between the contact lamellae and the slip ring when the slip ring is dynamically moving.

[0016] In particular, the sliding contact area, i.e., the track on the slip ring, is gold-plated or silver-plated. These materials possess high electrical conductivity, do not corrode, and always ensure optimal contact and thus the lowest possible contact resistance. To ensure a sufficient contact area between the slip ring and the contact medium, several contact lamellae are provided, which are subject to a defined contact force. This contact force is high enough to keep the contact lamellae in constant contact with the slip ring. The surrounding insulating fluid is not located within the contact area; it merely surrounds it.

[0017] The insulating fluid, preferably a mineral transformer oil or a synthetic ester fluid, allows for significantly reduced distances between current-carrying and non-current-carrying parts, particularly to the housing, due to its higher dielectric strength compared to air. This enables a smaller housing design. The contact system is virtually free of partial discharges. In both static and dynamic testing at a current of 400 A AC under transformer oil, partial discharges of < 10 pC were measured, with the baseline noise level already at 1 pC.

[0018] The slip ring assembly is preferably completely immersed in the insulating fluid, so that the air gaps between the 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. The insulators are also at least partially, and preferably completely, immersed in the insulating fluid.

[0019] 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 tetraglyceride esters. The ester-based fluid is non-toxic, readily biodegradable, and classified as non-hazardous to water.

[0020] To maximize the contact area of ​​the slip ring transmitter, it is preferably provided that the contact elements are in contact with the slip ring on both a top and a bottom surface. For this purpose, the slip ring has upper and lower contact tracks. The contact elements are preferably arranged on a common contact carrier that encompasses an edge of the slip ring. The contact carrier can be configured in a forked shape. It can consist of 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.

[0021] In a further advantageous design, the contact elements on the top and bottom surfaces of the slip ring are arranged radially offset on the contact carrier. Should a section of this contact track become worn, the fork-shaped contact carrier can be rotated 180° so that the unused, radially adjacent sections of the contact tracks on the top and bottom surfaces come into contact with the contact element. This effectively doubles the service life of the slip ring assembly without significant effort.

[0022] The contact carrier is preferably made of aluminum. The number of contact lamellae on the contact carrier is preferably relatively high to provide a sufficiently large contact area, thus reducing the contact forces per lamella, thereby reducing wear and extending maintenance intervals and service life. In particular, several contact carriers can be arranged distributed around the circumference of the slip ring.

[0023] In a further advantageous design, several contact lamellae are grouped together and resiliently arranged on a common lamella carrier. The lamella carrier itself can be fully integrated with the contact carrier. This allows for the simultaneous installation of many lamellae and their easy replacement as a set for maintenance or repair purposes. The lamella carrier with the contact lamellae can be supplied as a strip of material. This strip can be cut to the required length.

[0024] In a further development of the invention, toroids are positioned within the housing to homogenize the electric field. The toroids are arranged adjacent to and coaxial with the slip ring in the region of the at least one contact carrier. The toroids are made of an electrically conductive material. While the toroids do require some installation space, the homogenized field allows for a reduction in the distance between current-carrying components and the housing. The toroids serve to reduce the axial and radial dimensions of the slip ring transmitter housing. Preferably, several toroids are arranged axially spaced on both sides of a slip ring. At least one toroid should be located on the top side and one on the bottom side. The toroids can be mechanically connected to the slip ring. The toroids reduce and homogenize the electric field strength.Their shape prevents peak discharges on the live components.

[0025] Additional toroids with grounding potential can be provided in the housing at a distance from the toroids on the slip ring, thereby further reducing the overall height. The height can be reduced particularly effectively 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 of the same size, as are the radially outer toroids. The radially inner and outer toroids preferably have the same cross-sectional area. Four toroids can, for example, be arranged in a square, with the forked contact carrier positioned approximately in the center of the square. The slip ring should be enclosed by the toroids. The volume region 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, the material is completely homogenized by, in particular, four toroid-shaped toroids arranged in a square.

[0026] The goal of creating a slip ring transmission system with the most compact design possible for the transmission of high voltages is achieved particularly when at least one toroid and especially all toroids are arranged in the insulating fluid.

[0027] The invention achieves the goal of providing a slip ring transmitter system suitable for use in medium- and high-voltage applications, with a reduced housing size. The slip ring transmitter has multiple lamellae that do not float even during dynamic movement of the transmitter and are always subjected to sufficient contact pressure to prevent arcing between the lamellae and the slip ring. The insulating fluid allows for the use of more compact and smaller slip ring bodies, even at higher voltages. This enables the use of smaller housings, which is particularly advantageous in explosion-proof areas. The insulation distances within the housing and adjacent to the slip ring transmitter are significantly shorter than in slip ring transmitters operating in air. Additional toroids for homogenizing the electric field further contribute to the reduction in size.

[0028] The invention is explained in more detail below with reference to exemplary embodiments illustrated in schematic drawings. These show: Fig. 1 a perspective view of a contact carrier on a slip ring; Fig. 2 the contact carrier of the Fig. 1 in a side view; Fig. 3 the contact carrier of the Fig. 1 in a perspective from a low angle; Fig. 4 the contact carrier of the Fig. 1 in a perspective from a slightly elevated angle; Fig. 5 a lamellar carrier in a perspective view; Fig. 6. A slip ring in a perspective view; Fig. 7 a representation of the electric field in a cross-sectional plane through the slip ring of the Fig. 6; Fig. 8 an insulator in a side view and Fig. 9 the insulator of the Fig. 8 in longitudinal section.

[0029] The Fig. Figure 1 shows a section of a slip ring transmitter system S with an indicated housing 25 containing a slip ring transmitter 1. Neither the shape, position, nor distance of the depicted wall section of the housing 25 to the slip ring transmitter 1 are to scale in the figures, but are purely schematic.

[0030] Further components of the slip ring transmitter 1 are a slip ring 2 and a contact carrier 3, which is fork-shaped and overlaps a top surface 4 of the slip ring 2 as well as an underside 5 of the slip ring 2. The area overlapped on the top and underside is referred to as the sliding contact area 6.

[0031] The contact carrier 3 consists of an upper and a lower half 7, 8, both halves being configured essentially identically. The two halves project beyond an edge 9 of the slip ring 2 and are radially connected at their edges to form a common current-carrying shaft. They are screwed together. Fig. Figure 2 shows the cross-sectional view and the detailed structure. The contact carrier 3 carries in its upper half 7 and its lower half 8 a contact element 10 comprising several contact lamellae 12, as shown in the Fig. 3 to 5 can be identified. Fig. Figure 5 shows a lamellar carrier 11 with several identically configured lamellae 12 with essentially rectangular cross-sections. The lamellar carrier 11 with the contact lamellae is collectively referred to as the contact element and is attached once each to the upper part 7 of the contact carrier 3 and to the lower part 8, as shown by the Fig. 3 and Fig. As can be seen in Figure 4, the respective contact elements 10 and 11 are thus axially opposite each other, but are radially offset from one another in the 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 over, the adjacent areas of the sliding contact area 6 can come into contact with the lamellae 12. This reduces the local wear of the slip ring 4 or increases its service life before the surfaces reach their wear limit. The slip ring is, in particular, coated with silver or gold. The contact carrier is, in particular, made of brass.

[0032] The housing 25 is filled with an insulating fluid to such an extent that the insulating gaps between current-carrying and non-current-carrying components are filled by the insulating fluid. The insulating fluid is a mineral transformer oil or a synthetic ester fluid. The Fig. Components 1 to 5 shown are completely immersed in the insulating fluid. This allows for a reduction in the physical distances between current-carrying components, especially those to the grounded housing.

[0033] Another measure according to the invention for reducing the size of the building is described using the Fig. 6 and Fig. 7 explained. Fig. Figure 6 shows a slip ring 2 with dimensions differing from the Fig. 1 to 5. However, the same reference symbols are retained for functionally identical components. Fig. Figure 6 further shows a contact carrier 3. Additional 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 region of the contact carrier 3. In particular, there are four toroids 13-16, which are arranged according to the illustration in Figure 6. Fig. The 7 components are arranged in a square, with the contact carrier 3 and the edge 9 of the slip ring 4 located in the center of the square. The toroids 13-16 are arranged in pairs. Two concentric toroids 13, 14 are located on the upper side and axially offset from them, adjacent to the underside of the slip ring 4, are two further toroids 15, 16 of the same dimensions. The radially outer toroids 13, 15 have a diameter larger than the diameter of the slip ring 2. The diameter of the two other, radially inner toroids 14, 16 is smaller than the diameter of the slip ring 2.

[0034] The Fig. Figure 7 describes a single-phase slip ring transmitter design; in a three-phase design, the three identically constructed phases are arranged vertically stacked. Fig. Figure 7 illustrates that the toroids 13-16 homogenize the electric field that builds up around the current-carrying components. Additionally, according to the representation of the Fig. 7 Two further grounded toroids 17, 18 are arranged on the underside of the live toroids 13-16, and similarly, two further grounded toroids 19, 20 are arranged on the top side 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 in the housing 25, so that the overall height of the slip ring assembly can be significantly reduced in both the axial and radial directions.

[0035] The Fig. Figure 7 further shows an insulator 21 which is located in the Fig. 8 in the side view and in the Fig. Figure 9 shows a longitudinal section. The special feature of this insulator 21 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 (GFRP), are cast into the insulator. By avoiding metallic components, this insulator 21 possesses particularly advantageous properties for use in the slip ring transmitters according to the invention, which are intended to have a particularly small size and are to be used especially in explosion-proof areas or offshore wind turbines. Reference symbol: 1 slip ring transmitter 2 slip ring 3 contact carriers 4 Top of 2 5 Bottom of 2 6. Sliding contact area 7 upper part of 3 8 lower part of 3 9 rand of 2 10 contact agents 11 lamella carriers 12 contact strips 13 live toroid 14 live toroid 15 live toroid 16 live toroid 17 grounded toroid 18 grounded toroid 19 grounded toroid 20 grounded toroid 21 Insulator 22 Basic shapes 23 threaded rod 24 threaded rod 25 cases S slip ring transmitter system

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 by in that the slip ring (2) is held by at least one insulator (21) and / or the contact carrier (3) is held by at least one insulator (21) which has a base body (22), wherein the insulator (21) has at least one threaded rod (23, 24) made of a glass fibre reinforced plastic (GRP) cast into the base body (22) for fastening to adjacent components. [2] Slip ring transmission system (S) according to claim 1, characterized by that the base body (22) consists of an epoxy resin which is free of air inclusions. [3] Slip ring transmission system (S) according to claim 1, characterized bythat the threaded rod (23, 24) has the same shape inside and outside the base body (22).

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