GB2511373A - Improvements relating to vacuum switching devices - Google Patents
Improvements relating to vacuum switching devices Download PDFInfo
- Publication number
- GB2511373A GB2511373A GB1318392.6A GB201318392A GB2511373A GB 2511373 A GB2511373 A GB 2511373A GB 201318392 A GB201318392 A GB 201318392A GB 2511373 A GB2511373 A GB 2511373A
- Authority
- GB
- United Kingdom
- Prior art keywords
- arms
- coil assembly
- contact
- vacuum switching
- switching device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
- H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
- H01H33/66—Vacuum switches
- H01H33/664—Contacts; Arc-extinguishing means, e.g. arcing rings
- H01H33/6644—Contacts; Arc-extinguishing means, e.g. arcing rings having coil-like electrical connections between contact rod and the proper contact
Landscapes
- High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
Abstract
A vacuum switching device comprises an evacuated envelope having an insulator; a fixed electrode and a moving electrode which engage and disengage mechanically to perform switching and which include a contact of the axial field type comprising a coil assembly behind a contact disc. The coil assembly has between one and five arms which follow a curved path from a centre electrode to the outer diameter of the contact disc. The curved arms may be formed of successive circular arcs, be of constant width and have a constant separation from their neighbours. The coil can have two, three or four arms whose spiral path covers between 200, 130, 100 and 80 degrees of rotation respectively. The coil assembly can have radiused corners and edges to improve the voltage performance. The coil provides self-generated axial magnetic fields in the axis of the contact gap in order to make an arc diffuse over the contact surface at high currents.
Description
Improvements Relating To Vacuum Switching Devices
Description
This invention relates to improvements in vacuum switching devices, which may include for example vacuum interrupters or vacuum switches.
A simplified schematic diagram of a typical vacuum switching device is shown in figure 1. Vacuum switching devices generally consist of an evacuated envdope, which includes an insulating component (a), a fIxed electrode assembly tb), and a moving electrode assembly tIc). The electrodes consist of a conducting rod (d) and a contact assembly (e). The two contact assemblies include contact discs (f). The electrodes are designed to engage and disengage mechanically to perform the switching function. This movement is permitted without breaking the seal of the evacuated envelope by means of a bellows or diaphragm arrangement (g). Dunng switching an arc of electric cuiTent passes from one contact disc to the other. At low currents the arc is diffuse, that is, spread over the contact surfaces. Above a current of a few thousands of amps, due to aspects of the physics of the vacuum arc, the arc tends to constrict into a narrow column. This can cause overheating of pafts of the contact surfaces, which limits the level of current which can be successfully interrupted.
Vacuum switching devices that are designed to switch large culTents have been produced for many years. A number of different designs of electrode assemblies have been proposed for use under high current conditions, These designs use self-generated magnetic fields to control the arcs. The prior art falls into two categories, which work in different ways. In one category the contact geometry produces a radial magnetic field; in the other category the contact geometry produces an axial magnetic field. With radial magnetic field geometries the contact faces are generally in the form of annular rings, not discs, and a constricted arc is driven by the radia' magnetic field to continuously move around the ring, so that excessive heating is not produced at any one point. Examples are EP0525354 Al and US4553002 A. With axial magnetic field geometries the contact faces are generally in the form of discs, and the effect of the axial field is to diffuse the current arc fairly evenly over the contact surfaces, thereby preventing overheating of these surfaces. Examples of such designs may be seen in EP 0349303, DR 3915519, DR 3610241. GB 2381 1 IA. This invention concerns only
axial field contact assemblies.
Figure 2 shows construction features common to some of these axial arc electrode assemblies. The conducting rod (d) carries current to arm conductors (h) that cariy current via pillars (i) to the contact disc (I). Current is then carried across the vacuum to the other electrode disc by one or more arcs (j). The arm conductors of the two contact assemblies are arranged so that current circulates in the same sense in both arm conductors. The configuration of current flow produces a desired configuration of magnetic field which is generally in the axial direction of the contacts in the space between the contact discs and this magnetic field prevents constriction of the arcs.
The arm conductor assemblies are also known as coil assemblies.
This invention relates to one particular type of prior art contact geometry as typified by US 39946179. Figure 3 shows an exploded view of this geometry. The culTent path in the coil tIh) is radial from the centre to the penphery of the contact at which point it turns to follow the curve of the outside diameter of the contact disc. The design of coil assembly in US 39946179 is shown in plan view in figure 4.
This prior art geometry gives an axial magnetic field which is essentially concentrated at the outside diameter of the contact disc, which has the disadvantage that it gives a lower field at the inner part of the contact disc. It also gives rise to eddy currents in the contact disc, which, to one skilled in the art, is known to be detrimental to the generation of the axial magnetic field, reducing its effectiveness locally.
According to the invention, an embodiment of which is shown in figure 5. the coil assembfies each include curved arm conductors to provide the path along which the cunent flows. In this case the current path from the rod to the contact disc follows a curved path which gives additional axial magnetic field strength at the inner part of the contact disc and also reduces the eddy culTent effects, thereby improving the arc control capability of the contact assembly. Because this invention allows the current to follow a longer path than previous'y it also increases the overall strength of the axial magnetic field due to an increase in the effective number of coil turns for each contact arm.
This invention both improves the strength of the axial magnetic field generated and spreads the magnetic field over a larger surface area of the contact disc with a result that a higher current can be successfully interrupted for a given size of contact diameter, thereby making the vacuum switching device smaller and of lower cost.
An additional benefit of the invention is that the use of curved arms, as opposed to arms which include a sharp change in direction, significantly reduces electrostatic stress fields and thereby provides improved voltage performance for the vacuum switching device which is particubrly advantageous for high voliage applications.
In one form of the curved arms, illustrated in figure 5 for the case of four arms, the main part of the curve of each aim consists of successive sections of circular arc, the inner and outer radii of each section being of constant difference to yield a constant width of arm, and the radii and centres of successive sections being chosen to keep the gaps between each arm and its neighbours constant.
The invention may be applied to the design of vacuum switching devices over a wide range of contact diameters, the actual diameter chosen depending to a great extent on the intended maximum current to be interrupted, and the maximum load current intended to be canied.
A person skilled in the art will appreciate that this invention may be applied to variations of this basic geometry from one arm to many arms.
Claims (8)
- Claims: A vacuum switching device consisting of an evacuated envelope which includes an insulating component, a fixed electrode and a moving electrode which are designed to engage and disengage mechanically to perform the switching function and which includes at least one contact of the axial field type with a coil assembly behind a contact disc whereby the coil assembly has between one arm and five arms and the arms follow a curved path from the centre electrode to approximately the outside diameter of the contact disc.
- 2. A vacuum switching device consisting of an evacuated envelope which includes an insulating component, a fixed electrode and a moving electrode which are designed to engage and disengage mechanically to perform the switching function and which includes at least one contact of the axial field type with a coil assembly behind a contact disc whereby the coil assembly has between one arm and five arms and the arms follow a curved path from the centre electrode to approximately the outside diameter of the contact disc, and the main parts of the curved arms are formed of successive circular arcs.
- 3. A vacuum switching device consisting of an evacuated envelope which indudes an insulating component, a fixed electrode and a moving electrode which are designed to engage and disengage mechanically to perform the switching function and which includes at least one contact of the axial field type with a coil assemhly behind a contact disc whereby the coil assembly has between one arm and five arms and the arms follow a curved path from the centre electrode to approximately the outside diameter of the contact disc, and the main parts of the curved arms are formed of successive circular arcs, and are of constant width and have constant separation from their neighbours.
- 4. A vacuum switching device as described in Claims 1, 2 or 3 whereby the coil assembly has two arms and the spiral path covers more than 2000 of rotation.
- 5. A vacuum switching device as described in Claims 1, 2 or 3 whereby the coil assembly has three arms and the spiral path covers more than i30° of rotation.
- 6. A vacuum switching devicc as described in Claims 1, 2 or 3 whereby the coil assembly has four arms and the spiral path covers more than 100° of rotation.
- 7. A vacuum switching device as described in Claims 1, 2 or 3 whereby the coil assembly has five arms and the spiral path covers more than 80° of rotation.
- 8. A vacuum switching device as described in claims 1, 2 or 3 whereby the coil assembly has radiused corners and edges to improve voltage performance.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1218975.9A GB2507262A (en) | 2012-10-23 | 2012-10-23 | Spiral contact coil for vacuum switch |
Publications (3)
Publication Number | Publication Date |
---|---|
GB201318392D0 GB201318392D0 (en) | 2013-12-04 |
GB2511373A true GB2511373A (en) | 2014-09-03 |
GB2511373B GB2511373B (en) | 2018-01-03 |
Family
ID=47359290
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1218975.9A Withdrawn GB2507262A (en) | 2012-10-23 | 2012-10-23 | Spiral contact coil for vacuum switch |
GB1318392.6A Active GB2511373B (en) | 2012-10-23 | 2013-10-17 | Vacuum switching device having axial field contacts |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1218975.9A Withdrawn GB2507262A (en) | 2012-10-23 | 2012-10-23 | Spiral contact coil for vacuum switch |
Country Status (1)
Country | Link |
---|---|
GB (2) | GB2507262A (en) |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1478702A (en) * | 1973-09-10 | 1977-07-06 | Tokyo Shibaura Electric Co | Vacuum interrupter |
DE3112407A1 (en) * | 1981-03-28 | 1982-04-08 | Calor-Emag Elektrizitäts-Aktiengesellschaft, 4030 Ratingen | Switching contact for vacuum switches |
DE3107155A1 (en) * | 1981-02-26 | 1982-09-09 | Calor-Emag Elektrizitäts-Aktiengesellschaft, 4030 Ratingen | Vacuum switch |
DE3130466A1 (en) * | 1981-07-23 | 1983-02-17 | Calor-Emag Elektrizitäts-Aktiengesellschaft, 4030 Ratingen | Contact for a vacuum switch |
DE3338254A1 (en) * | 1983-10-21 | 1984-03-08 | Ritter Starkstromtechnik GmbH & Co, 4600 Dortmund | Contact arrangement for vacuum switches |
DE3318226A1 (en) * | 1983-05-19 | 1984-11-22 | Sachsenwerk, Licht- und Kraft-AG, 8000 München | Vacuum switch with double interruption |
US4553002A (en) * | 1983-12-05 | 1985-11-12 | Westinghouse Electric Corp. | Axial magnetic field vacuum-type circuit interrupter |
DE4446672A1 (en) * | 1994-12-15 | 1996-09-12 | Slamecka Ernst | Vacuum switch contact arrangement for medium- to high-voltage equipment |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2643036B2 (en) * | 1991-06-17 | 1997-08-20 | 三菱電機株式会社 | Vacuum switch tube |
-
2012
- 2012-10-23 GB GB1218975.9A patent/GB2507262A/en not_active Withdrawn
-
2013
- 2013-10-17 GB GB1318392.6A patent/GB2511373B/en active Active
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1478702A (en) * | 1973-09-10 | 1977-07-06 | Tokyo Shibaura Electric Co | Vacuum interrupter |
DE3107155A1 (en) * | 1981-02-26 | 1982-09-09 | Calor-Emag Elektrizitäts-Aktiengesellschaft, 4030 Ratingen | Vacuum switch |
DE3112407A1 (en) * | 1981-03-28 | 1982-04-08 | Calor-Emag Elektrizitäts-Aktiengesellschaft, 4030 Ratingen | Switching contact for vacuum switches |
DE3130466A1 (en) * | 1981-07-23 | 1983-02-17 | Calor-Emag Elektrizitäts-Aktiengesellschaft, 4030 Ratingen | Contact for a vacuum switch |
DE3318226A1 (en) * | 1983-05-19 | 1984-11-22 | Sachsenwerk, Licht- und Kraft-AG, 8000 München | Vacuum switch with double interruption |
DE3338254A1 (en) * | 1983-10-21 | 1984-03-08 | Ritter Starkstromtechnik GmbH & Co, 4600 Dortmund | Contact arrangement for vacuum switches |
US4553002A (en) * | 1983-12-05 | 1985-11-12 | Westinghouse Electric Corp. | Axial magnetic field vacuum-type circuit interrupter |
DE4446672A1 (en) * | 1994-12-15 | 1996-09-12 | Slamecka Ernst | Vacuum switch contact arrangement for medium- to high-voltage equipment |
Also Published As
Publication number | Publication date |
---|---|
GB2511373B (en) | 2018-01-03 |
GB201218975D0 (en) | 2012-12-05 |
GB201318392D0 (en) | 2013-12-04 |
GB2507262A (en) | 2014-04-30 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) |
Free format text: REGISTERED BETWEEN 20190801 AND 20190807 |