Slip ring transmitter system

Abstract

Slip ring transmitter system (S) comprising a slip ring transmitter (1), which is arranged in a housing (25) and has at least one slip ring (2) rotatably mounted in the housing (25), and comprising at least one contact support (3), which supports at least one contact means which pushes against the dynamically moving slip ring (2), wherein, for the purpose of homogenizing the electric field, at least one voltage-carrying toroid (13-16) composed of an electrically conductive material is arranged adjacent and coaxially to the slip ring (2) in the region of the at least one contact support (3), the toroid (13-16) being at the voltage potential of the slip ring (2).

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 assembly systems are used to transmit power or data. At higher voltages above 35 kV and with air insulation, the structural complexity for slip ring assembly housings increases considerably because the insulation distance between live parts of the contact system and the grounded housing, which is required to prevent partial discharge, inevitably increases. This significantly increases the external dimensions of the housings, i.e., their size and weight. Particularly in explosion-protected areas, size plays a key role and should be as small as possible. Examples of this are explosion-protected areas for FPSO (Floating Production Storage and Offloading) vessels or in offshore wind turbines. DE 28 33 129 A1 discloses a slip ring assembly for electrical machines for transmitting power between mutually rotating machine parts.The slip rings have conductor connections on the inside and are contacted radially on the outside by slip ring brushes. The slip rings are insulated and spaced from each other by insulating rings and are secured to each other relative to a support body by an internally mountable bracket. The slip rings and insulating bodies are held in place by a symmetrically compressed, central clamping bolt.

[0004] DE 18 54 488 U relates to slip ring bodies in which the insulating bodies are arranged offset from one another in such a way that the air gap distance from slip ring to slip ring can be reduced while maintaining the same creepage distances.

[0005] DE 101 61 740 A1 discloses a slip ring assembly that can be manufactured and operated more economically with a smaller diameter using coal / coal technology. It is proposed to embed a circumferentially closed inner ring made of a non-ferrous metal, in particular brass, in an insulating compound as a component of a rotor. The insulating compound can be epoxy resin, for example. The inner ring is electrically contacted with an electrical connection assigned to the rotor and, from there, connected to a cable gland on the front.

[0006] The task is to demonstrate a slip ring transmission system that can transmit higher voltages greater than 35 kV without increasing the size of the slip ring transmission system too much and yet is almost free of partial discharges under static and dynamic loads.

[0007] This object is achieved in a slip ring transmission system having the features of patent claim 1.

[0008] The subclaims relate to advantageous developments of the invention.

[0009] 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.

[0010] According to the invention, toroids are arranged 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 the at least one contact carrier. The toroids are made of an electrically conductive material.

[0011] Although the toroids require a certain amount of space in the housing, the homogenized field allows the distance between current-carrying components and the housing to be significantly reduced. The toroids serve to reduce the internal dimensions of the housing, both axially and radially. This also makes the housing smaller in its external dimensions. The size, material usage, and weight are all reduced.

[0012] Preferably, several toroids are arranged at axial spacing on both sides of a slip ring. At least one toroid should be arranged on the top side and one on the bottom side in the axial direction of the slip ring. 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.

[0013] In a further development of the invention, additional toroids with ground potential are provided in the housing at a distance from the toroids on the slip ring, which allows the overall height to be further reduced. 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.

[0014] For example, four toroids can be arranged in a square, with the forked contact carrier located approximately in the center of the square. The slip ring should be enclosed by the toroids, meaning that the multiple toroids together surround a hollow cylindrical volume, in whose cylindrical wall the slip ring and contact carrier are arranged.

[0015] The highest field strength concentrations occur 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. This volume region is completely homogenized by four toroidal toroids arranged in a square.

[0016] Preferably, all toroids are immersed in an insulating fluid. The insulating fluid surrounding the current-carrying parts must not act as an insulating fluid between the sliding contact and the contact segments. Therefore, the contact force of the contact body on the slip ring is so great that it always rests against the slip ring, even when immersed in the insulating fluid. The surrounding insulating fluid is not in the contact area; it merely surrounds it.

[0017] 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, particularly to the housing, can be significantly reduced. The housing can therefore be made smaller in its external dimensions. The contact system is practically free of partial discharges. In both static and dynamic tests under transformer oil, partial discharges of < 10 pC were measured at a current of 400 A AC for the design according to the invention, with the background noise level already being 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 transmission system is completely filled with the insulating liquid.

[0018] 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.

[0019] To maximize the contact area of ​​the slip ring assembly, 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 fork-shaped for this purpose. 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] The invention achieves the goal of providing a slip-ring assembly system suitable for use in medium- and high-voltage applications while reducing the size of the housing. The toroids homogenize the electric field within the housing and thus contribute to reducing the size of the housing despite their size. The insulation distances within the housing or adjacent to the slip-ring assembly are significantly shorter than in slip-ring assembly systems without toroids. An insulating fluid can further reduce the insulation distances.

[0024] The voltage-carrying components of the slip-ring transmission system, i.e., the slip ring, are preferably held by at least one insulator and / or the contact carrier is preferably held by at least one insulator. For attachment to adjacent components, the insulator preferably has at least one threaded rod made of glass-fiber-reinforced plastic (GRP) cast into a base body. The insulator therefore has no metallic components. The base body is preferably made of an epoxy resin. The epoxy resin is preferably free of air inclusions.

[0025] 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 held by casting the material of the base body. The thread of the threaded rod is preferably continued identically outside the base body. This threaded rod design is the simplest from a manufacturing perspective.

[0026] Alternatively or in addition to the thread, anchoring means can be formed on the threaded rod, such as projections or depressions that differ from the thread shape, in order to improve the positive connection between the material of the base body and the threaded rod, i.e. to improve the pull-out security of the threaded rod in the longitudinal direction and / or the torsion security. The insulating bodies preferably have a profiled surface in order to extend the creepage distance. They are preferably long-rod insulators. The ends of the base body are therefore at a relatively large distance from one another. The creepage distance is correspondingly long. The threaded rods are preferably located in the central longitudinal axis of the base body. They are spaced from one another so that the core of the base body, i.e. the area between the respective inner ends of the threaded rods, is formed exclusively by the epoxy resin.The threaded rods are specifically 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 transmission system.

[0027] Such insulators are particularly well suited to the desired compact design of the slip ring transmission system and complement the positive effects of the toroids and the insulating fluid.

[0028] The invention is explained in more detail below with reference to exemplary embodiments illustrated in schematic drawings. They show:

[0029] Figure 1 is a perspective view of a contact carrier on a slip ring;

[0030] Figure 2 shows the contact carrier of Figure 1 in a side view;

[0031] Figure 3 shows the contact carrier of Figure 1 in a perspective obliquely from below;

[0032] Figure 4 shows the contact carrier of Figure 1 in a perspective obliquely from above;

[0033] Figure 5 shows a slat carrier in a perspective view;

[0034] Figure 6 shows a slip ring in a perspective view;

[0035] Figure 7 is a representation of the electric field in a sectional plane through the slip ring of Figure 6;

[0036] Figure 8 shows an insulator in a side view and

[0037] 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.

[0038] Further components of the slip ring assembly 1 are a slip ring 2 and a contact carrier 3, which is fork-shaped here 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.

[0039] 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 means 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 laminations 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 provided, in particular, with a silver or gold coating. The contact carrier is made, in particular, of brass. The housing 25 is filled with an insulating fluid to such an extent that the insulating 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.

[0040] A measure according to the invention for reducing the overall 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. Additional contact carriers 3 can be arranged distributed around the circumference. To homogenize the electrical 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 ?, 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.

[0041] 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 ? 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 liquid, so that the overall height of the slip ring assembly can be significantly reduced in the axial and radial directions.

[0042] 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 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 (GRP) have been cast into the insulator. 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.

[0043] Reference symbol:

[0044] 1 - Slip ring assembly

[0045] 2 - Slip ring

[0046] 3 - Contact carrier

[0047] 4 - Top of 2

[0048] 5 - Bottom of 2

[0049] 6 - Sliding contact area

[0050] 7 - upper part of 3

[0051] 8 - lower part of 3

[0052] 9 - Edge of 2

[0053] 10 - Contact agent

[0054] 11 - Slat carrier

[0055] 12 - Contact lamella

[0056] 13 - voltage-carrying toroid

[0057] 14 - voltage-carrying toroid

[0058] 15 - voltage-carrying toroid

[0059] 16 - voltage-carrying toroid

[0060] 17 - grounded toroid

[0061] 18 - grounded toroid

[0062] 19 - grounded toroid

[0063] 20 - grounded toroid

[0064] 21 - Insulator

[0065] 22 - Base body

[0066] 23 - Threaded rod

[0067] 24 - Threaded rod 25 - Housing

[0068] S - Slip ring assembly

Claims

Patent claims 1. Slip ring transmitter system (S) with a slip ring transmitter (1) arranged in a housing (25) with at least one rotatably mounted 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 for homogenizing the electric field adjacent to and coaxial with the slip ring (2) in the region of the at least one contact carrier (3) at least one voltage-carrying toroid (13-16) made of an electrically conductive material is arranged, wherein the toroid (13-16) is at the voltage potential of the slip ring (2).

2. Slip ring transmission system (S) according to claim 1, characterized in that several of the toroids (13-16) are arranged at an axial distance on both sides of a slip ring (2).

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

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