EP0771018A2 - Magnetic actuator arrangement - Google Patents
Magnetic actuator arrangement Download PDFInfo
- Publication number
- EP0771018A2 EP0771018A2 EP96307626A EP96307626A EP0771018A2 EP 0771018 A2 EP0771018 A2 EP 0771018A2 EP 96307626 A EP96307626 A EP 96307626A EP 96307626 A EP96307626 A EP 96307626A EP 0771018 A2 EP0771018 A2 EP 0771018A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- armature
- spindle
- magnetic actuator
- actuator arrangement
- bushes
- 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.)
- Withdrawn
Links
- 230000000694 effects Effects 0.000 abstract 1
- 239000004677 Nylon Substances 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H50/00—Details of electromagnetic relays
- H01H50/16—Magnetic circuit arrangements
- H01H50/18—Movable parts of magnetic circuits, e.g. armature
- H01H50/24—Parts rotatable or rockable outside coil
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H50/00—Details of electromagnetic relays
- H01H50/16—Magnetic circuit arrangements
- H01H50/18—Movable parts of magnetic circuits, e.g. armature
- H01H50/30—Mechanical arrangements for preventing or damping vibration or shock, e.g. by balancing of armature
- H01H50/305—Mechanical arrangements for preventing or damping vibration or shock, e.g. by balancing of armature damping vibration due to functional movement of armature
-
- 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
- H01H33/02—Details
- H01H33/022—Details particular to three-phase circuit breakers
-
- 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
- H01H33/666—Operating arrangements
Definitions
- the invention concerns a magnetic actuator arrangement comprising one or more electromagnets attached to a frame and an armature pivotably attached to the frame, and in particular, but not exclusively, a magnetic actuator arrangement for operating one or more vacuum switching devices.
- FIG. 1 A known magnetic actuator arrangement is shown in Figure 1.
- This magnetic actuator arrangement which is part of a vacuum contactor chassis developed by the applicants, comprises a pair of electromagnets 10, 11 fixed to a frame 12 on a transverse member 13 thereof, and an "L"-shaped armature 14 with a welded- or brazed-on spindle 15 resting in a pair of ball-joint bearings 16 fixed to respective vertical members 17 of the frame 12.
- the electromagnets 10, 11 each have a pole piece 21, 22 and a vertical portion 18 of the armature 14 is positioned so that, in an unenergised state of the actuator, it is spaced apart from the pole pieces 21, 22, the necessary gap being maintained by a pair of springs 23, 24 which are fixed to the transverse member 13 and act against the vertical portion 18 of the armature 14.
- the horizontal portion 19 of the armature 14 is linked by a suitable linkage arrangement (not shown) to the actuator rods 25 of a group of three vacuum switches 26 (shown only very schematically), one for each phase of an AC system with which the switching apparatus is to be used.
- the switches 26 are mounted on a subframe 20, which is fixed to the vertical members 17, and are equipped with high-voltage terminals 27, 28 for connection to the AC system.
- the actuator design shown in Figure 1 employs an accurately adjustable bearing system in the form of the ball joints 16 (see Figure 2), each of which is attached to a side 30 of the vertical member 17 by a thread-and-nut arrangement 31, this arrangement allowing fine backward and forward adjustment of the armature relative to the pole pieces 21, 22.
- the hole 34 in the frame member 17 through which the spindle 15 passes is arranged to be significantly larger than the diameter of the spindle.
- a magnetic actuator arrangement comprising one or more electromagnets attached to a frame and an armature pivoted in one or more bearings disposed in said frame, a portion of said armature being attracted to said electromagnets when the latter are energised, said armature having a spindle which is a loose radial fit in said bearings.
- Each of said bearings may be constituted by a bush located in said frame.
- the actuator arrangement may comprise two electromagnets and two bushes, said bushes being disposed at opposite ends of said frame.
- the total clearance between the spindle and the bush may be greater than 0.2mm.
- an electrical switching apparatus comprising a magnetic actuator arrangement as described above, in which said apparatus to be actuated is one or more switching devices. These devices may be vacuum, air, oil or SF 6 switches, for example.
- the magnetic actuator arrangement of the present invention employs, instead of the expensive ball joints 16 of the known arrangement, a simple plain bearing in the form of a bush 40 inserted as an interference fit in a hole 41 in each of the frame members 17.
- the lip 42 of the bush 40 is situated inside the frame 12 so that, when the armature with its spindle 15 is in place, the bushes are kept from being dislodged by the presence of the armature.
- the bushes 40 have an inside diameter 43 which is significantly larger than the diameter of the spindle 15. The difference may be of the order of 0.5mm.
- the spindle 15 In an unenergised state of the actuator, due to the restoring action of the springs 23, 24 the spindle 15 will lie approximately in the position shown in Figure 5(a); however, when current is supplied to the electromagnets 10, 11, the attractive force on the armature 14 will tend to lift the spindle while it is turning, so that the spindle will assume a new position approximately as illustrated in Figure 5(b).
- This ability of the spindle to move inside the bearing in the plane of the principle face of the frame member 17 i.e. radially with respect to the bushes 40) enables the armature to take up a properly seated position relative to the pole pieces 21, 22 of the electromagnets 10, 11, while at the same time executing its normal rotating movement within the bearing.
- the amount of allowable non-rotational movement of the spindle inside the bearing is always arranged to be significantly less than the amount of vertical movement available (e.g. 3-4mm) at the point of action of the portion 19 of the armature on the actuator rods 25, so that correct switching operation of the contactor chassis is not impaired.
- the spindle 15 is never in full contact with the bush bearing 40 and wear on the latter is therefore minimal.
- a nylon composition as a preferred material for the bush 40, it has been found that in a test chassis of the above-described design which has been subjected to over 3,000,000 operating cycles, the bushes have exhibited virtually no wear at all.
- the armature shape so far described is a preferred one, since it allows a fairly compact switching unit to be produced.
- an armature of any shape e.g. straight instead of "L"-shaped
- the armature always performs its required relay action, i.e. is able to translate the attractive movement of the portion of the armature near the magnets into some other desired movement at a distant point.
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
- Electromagnets (AREA)
Abstract
Description
- The invention concerns a magnetic actuator arrangement comprising one or more electromagnets attached to a frame and an armature pivotably attached to the frame, and in particular, but not exclusively, a magnetic actuator arrangement for operating one or more vacuum switching devices.
- A known magnetic actuator arrangement is shown in Figure 1. This magnetic actuator arrangement, which is part of a vacuum contactor chassis developed by the applicants, comprises a pair of
electromagnets frame 12 on atransverse member 13 thereof, and an "L"-shaped armature 14 with a welded- or brazed-onspindle 15 resting in a pair of ball-joint bearings 16 fixed to respectivevertical members 17 of theframe 12. - The
electromagnets pole piece vertical portion 18 of thearmature 14 is positioned so that, in an unenergised state of the actuator, it is spaced apart from thepole pieces springs transverse member 13 and act against thevertical portion 18 of thearmature 14. - The
horizontal portion 19 of thearmature 14 is linked by a suitable linkage arrangement (not shown) to theactuator rods 25 of a group of three vacuum switches 26 (shown only very schematically), one for each phase of an AC system with which the switching apparatus is to be used. Theswitches 26 are mounted on asubframe 20, which is fixed to thevertical members 17, and are equipped with high-voltage terminals - In operation, current is supplied to the
electromagnets armature portion 18 is attracted against thesprings pole pieces bearings 16 at each side of theframe 12, so that thehorizontal portion 19 of the armature is moved downwards, moving theactuator rods 25 of theswitches 26 from an "open" to a "closed" position of the contactor. At the same time, a further linkage arrangement (not shown) actuated by thearmature 14 operates two auxiliary switches 29 (shown only in plan view), thereby providing auxiliary signals and power for use in other, external equipment. - One potential problem with the arrangement just described is that, unless the face of the
armature portion 18 sits exactly square against thepole pieces side 30 of thevertical member 17 by a thread-and-nut arrangement 31, this arrangement allowing fine backward and forward adjustment of the armature relative to thepole pieces hole 34 in theframe member 17 through which thespindle 15 passes is arranged to be significantly larger than the diameter of the spindle. - Because the
ball joints 16 are secured not to the main faces of themembers 17 but to thesides 30 thereof, it is necessary to strengthen this part of the frame by the addition ofscrewed rods 32 and associatednuts 33 close to the ball-joint fixing points. - In practice, it is often necessary to adjust both bearings to achieve perfect seating of the armature against the pole pieces, and this is almost invariably the case when two magnets are employed, as here. Such adjustment requires the intervention of skilled technical personnel and this, together with the need for the precision ball-
joints 16 and the reinforcingitems - In accordance with a first aspect of the invention, there is provided a magnetic actuator arrangement, comprising one or more electromagnets attached to a frame and an armature pivoted in one or more bearings disposed in said frame, a portion of said armature being attracted to said electromagnets when the latter are energised, said armature having a spindle which is a loose radial fit in said bearings.
- Each of said bearings may be constituted by a bush located in said frame.
- The actuator arrangement may comprise two electromagnets and two bushes, said bushes being disposed at opposite ends of said frame.
- The total clearance between the spindle and the bush may be greater than 0.2mm.
- In accordance with a second aspect of the invention, there is provided an electrical switching apparatus, comprising a magnetic actuator arrangement as described above, in which said apparatus to be actuated is one or more switching devices. These devices may be vacuum, air, oil or SF6 switches, for example.
- An embodiment of the invention will now be described, by way of example only, with reference to the drawings, of which:
- Figure 1 shows front, side and plan views of a vacuum contactor chassis incorporating a known magnetic actuator arrangement;
- Figure 2 is a section along the line II-II in Figure 1;
- Figure 3 is a section along the line II-II in Figure 1 for an equivalent vacuum contactor chassis incorporating a magnetic actuator arrangement according to the invention;
- Figure 4 is a view of the section of Figure 3 looking from the right, and
- Figure 5 shows a typical lie of the armature of a magnetic actuator arrangement according to the invention for (a) an unenergised and (b) an energised state of the actuator.
- Referring now to Figures 3 and 4, the magnetic actuator arrangement of the present invention employs, instead of the
expensive ball joints 16 of the known arrangement, a simple plain bearing in the form of abush 40 inserted as an interference fit in ahole 41 in each of theframe members 17. Thelip 42 of thebush 40 is situated inside theframe 12 so that, when the armature with itsspindle 15 is in place, the bushes are kept from being dislodged by the presence of the armature. - The
bushes 40 have an inside diameter 43 which is significantly larger than the diameter of thespindle 15. The difference may be of the order of 0.5mm. In an unenergised state of the actuator, due to the restoring action of thesprings spindle 15 will lie approximately in the position shown in Figure 5(a); however, when current is supplied to theelectromagnets armature 14 will tend to lift the spindle while it is turning, so that the spindle will assume a new position approximately as illustrated in Figure 5(b). This ability of the spindle to move inside the bearing in the plane of the principle face of the frame member 17 (i.e. radially with respect to the bushes 40) enables the armature to take up a properly seated position relative to thepole pieces electromagnets - The amount of allowable non-rotational movement of the spindle inside the bearing is always arranged to be significantly less than the amount of vertical movement available (e.g. 3-4mm) at the point of action of the
portion 19 of the armature on theactuator rods 25, so that correct switching operation of the contactor chassis is not impaired. - In contrast to the conventional bearing arrangement, the
spindle 15 is never in full contact with thebush bearing 40 and wear on the latter is therefore minimal. Indeed, using a nylon composition as a preferred material for thebush 40, it has been found that in a test chassis of the above-described design which has been subjected to over 3,000,000 operating cycles, the bushes have exhibited virtually no wear at all. - The armature shape so far described is a preferred one, since it allows a fairly compact switching unit to be produced. However, it is possible to have an armature of any shape (e.g. straight instead of "L"-shaped) to suit a particular application, provided the armature always performs its required relay action, i.e. is able to translate the attractive movement of the portion of the armature near the magnets into some other desired movement at a distant point.
- Also, although the use of two electromagnets has been assumed, it may, depending on the particular application, be possible to use only one electromagnet or, on the other hand, even more than two. Use of more than two magnets, however, may well require a greater clearance between the bushes and the armature spindle than would be the case with only one or two magnets.
Claims (5)
- A magnetic actuator arrangement, comprising one or more electromagnets (10, 11) attached to a frame (12) and an armature (14) pivoted in one or more bearings (40) disposed in said frame (12), a portion of said armature (14) being attracted to said electromagnets (10, 11) when the latter are energised, said armature (14) having a spindle (15) which is a loose radial fit in said bearings (40).
- A magnetic actuator arrangement as claimed in Claim 1, in which each of said bearings is constituted by a bush (40) located in said frame.
- A magnetic actuator arrangement as claimed in Claim 2, comprising two electromagnets (10, 11) and two bushes (40), said bushes (40) being disposed at opposite ends of said frame (12).
- A magnetic actuator arrangement as claimed in any one of the preceding claims, in which an outside diameter of said spindle (15) is at least 0.2mm less than an inside diameter of said bush (40).
- An electrical switching apparatus, comprising a magnetic actuator arrangement as claimed in any one of the preceding claims, in which said apparatus to be actuated is one or more switching devices.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9521822A GB2306788B (en) | 1995-10-25 | 1995-10-25 | Magnetic actuator arrangement |
GB9521822 | 1995-10-25 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0771018A2 true EP0771018A2 (en) | 1997-05-02 |
EP0771018A3 EP0771018A3 (en) | 1998-08-19 |
Family
ID=10782870
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96307626A Withdrawn EP0771018A3 (en) | 1995-10-25 | 1996-10-21 | Magnetic actuator arrangement |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0771018A3 (en) |
GB (1) | GB2306788B (en) |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB359420A (en) * | 1930-07-21 | 1931-10-21 | Allen West & Co Ltd | Improvements in or relating to electromagnetic switches |
NL99853C (en) * | 1954-08-27 |
-
1995
- 1995-10-25 GB GB9521822A patent/GB2306788B/en not_active Expired - Fee Related
-
1996
- 1996-10-21 EP EP96307626A patent/EP0771018A3/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
None |
Also Published As
Publication number | Publication date |
---|---|
GB9521822D0 (en) | 1996-01-03 |
EP0771018A3 (en) | 1998-08-19 |
GB2306788B (en) | 2000-04-26 |
GB2306788A (en) | 1997-05-07 |
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Owner name: ALSTOM UK LTD |
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17P | Request for examination filed |
Effective date: 19990211 |
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17Q | First examination report despatched |
Effective date: 20030314 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
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18W | Application withdrawn |
Effective date: 20031107 |