Molded pole automatic circuit recloser with bistable electromagnetic actuator

• US 5,912,604 A
• Filed: 02/04/1997
• Issued: 06/15/1999
• Est. Priority Date: 02/04/1997
• Status: Expired due to Term

• Current Assignee: ABB Incorporated (ABB Limited)
• Original Assignee: ABB Power T&D Co Inc (ABB Limited)
• Inventors: Smith, James E., Khan, Aftab H., Harvey, Ian James, Smith, Robert A.
• Primary Examiner(s): Luebke, Renee S.
• Assistant Examiner(s): Nguyen, Tuyen T.
• Application Number:
  US08/794,491
• Time in Patent Office: 861 Days
• Field of Search: 335/9, 335/177-179, 335/234, 335/236, 335/229, 335/251, 335/255, 218/138, 218/140
• US Class Current: 335/9
• CPC Class Codes: H01F 2007/1669 Armatures actuated by current pulse, e.g. bistable actuators
• CPC Class Codes: H01H 2009/0292 Transparent window or opening, e.g. for allowing visual inspection of contact position or contact condition
• CPC Class Codes: H01H 2033/6623 Details relating to the encasing or the outside layers of the vacuum switch housings
• CPC Class Codes: H01H 33/027 Integrated apparatus for measuring current or voltage
• CPC Class Codes: H01H 33/6662 using bistable electromagnetic actuators, e.g. linear polarised electromagnetic actuators
• CPC Class Codes: H01H 75/00 Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of power reset mechanism
• CPC Class Codes: H01H 75/04 Reset mechanisms for automatically reclosing a limited number of times circuit arrangements H02H3/06
• CPC Class Codes: H01H 9/16 Indicators for switching condition, e.g. "on" or "off"

Abstract

An electromagnetic actuator and an automatic recloser incorporating such actuator are disclosed. The actuator is shown to include a housing, a permanent magnet member, a coil, an armature, mounted to move axially within the housing between first and second positions, and a non-magnetic spacer. The armature, when in the second position, is spaced a distance from the housing by the spacer. The spacer is mounted to stop movement of the armature in the second position. In the preferred embodiment, the permanent magnet member includes a core and a number of magnet segments attached thereto. It is especially preferred for each of the permanent magnet segments to be arcuate shaped and that each segment be polarized substantially radially or in a direction parallel to the center radius of each segment. In a preferred embodiment, the housing is formed from a material having a high permeability and the spacer is formed from material having a relative permeability close to one or from a substantially non-magnetic material, such as acetal resin.

The circuit recloser is shown to include the bistable magnetic actuator, a contact switch, a connecting member, connected between the actuator the contact switch and a spring, connected to bias the connecting member in relation to the contact switch. When the actuator is in its second position the end of the connecting member is spaced from the end of the contact switch, i.e., over travel is present. An indicator is provided for indicating whether the contact switch is open or closed.

Claims

1. An electromagnetic actuator, comprising:

a housing;

a permanent magnet member, mounted in said housing;

a coil, mounted in said housing, said coil and said permanent magnet defining a cavity within said housing;

an armature, mounted in said housing, wherein said armature moves axially within said cavity between first and second positions;

a non-magnetic spacer, mounted within said housing at one end of said cavity, whereby said armature when in said second position is spaced by said spacer a distance from the end of said housing adjacent said spacer; and

a spring, mechanically connected to said armature, for biasing said armature towards said second position.

2. The actuator of claim 1, wherein said spacer is mounted to stop the movement of said armature in said second position.

3. The actuator of claim 1, wherein said permanent magnet member comprises a core and a number of magnet segments attached thereto.

4. The actuator of claim 3, wherein said cavity is generally cylindrical and wherein each of said permanent magnet segments comprises an arcuate shaped.

5. The actuator of claim 4, wherein said segments are polarized substantially radially in relation to said cavity.

6. The actuator of claim 5, wherein each of said segments has a center radius and wherein the polarization of each of said segments is in a direction parallel to the center radius of said segment.

7. The actuator of claim 1, wherein said permanent magnet is formed from an anisotropic material.

8. The actuator of claim 7, wherein said anisotropic material comprises Neodymium Iron Boron.

9. The actuator of claim 1, wherein said housing is formed from a material having a high permeability and wherein said spacer is formed from material having a relative permeability close to one.

10. The actuator of claim 1, wherein said spacer is formed from a substantially non-magnetic material.

11. The actuator of claim 9, wherein said spacer is formed from acetal resin.

12. The actuator of claim 1, further comprising a second biasing spring.

13. A circuit recloser, comprising:

a bistable magnetic actuator, adapted for moving an actuating rod between first and second positions;

a contact switch, said contact switch having an end;

a connecting member, connected between said actuator rod and said contact switch, said connecting member connected to slidably engage said contact switch, wherein when said actuator rod is in said second position the end of said connecting member is spaced from the end of said contact switch; and

a spring, connected to bias said connecting member in relation to said contact switch.

14. The reclosers of claim 13, further comprising an indicator for indicating whether said contact switch is open or closed.

15. The reclosers of claim 14, wherein said indicator comprises first and second concentric rings, wherein said first ring is made visible to indicate closed contacts and said second ring is made visible to indicate open contacts.

16. The reclosers of claim 15, further comprising a housing in which said actuator is mounted, wherein said first ring is connected to said actuator and said second ring is connected to said housing.

17. The reclosers of claim 13, further comprising a manual lever, connected to mechanically engage said actuator for moving said actuator, thereby moving said contact switch.

18. The recloser of claim 13, further comprising a molded pole, wherein said contact switch is encapsulated in said molded pole.

19. The reclosers of claim 18, wherein said molded pole comprises polyurethane.

20. The reclosers of claim 13, wherein said contact switch comprises a vacuum contact closure assembly.

21. The reclosers of claim 20, wherein said contact closure assembly comprises a housing and further comprising a layer of bonding material applied to said housing.

22. A reclosers assembly, comprising:

a bistable magnetic actuator;

a contact closure assembly;

a molded pole, wherein said contact closure assembly is encapsulated in said molded pole, and wherein said actuator is attached to said molded pole;

a connecting member for connecting said actuator to said closure assembly, wherein movement of said connecting member slidably engages said contact closure assembly;

a spring, connected to bias said connecting member away from said contact closure assembly; and

a fastening plate, attached to said molded pole, for attachment of said molded pole.

23. A reclosers assembly, comprising:

a bistable magnetic actuator;

a plurality of contact closure assemblies;

a plurality of molded poles, wherein each of said contact closure assemblies is encapsulated in a molded pole; and

a connecting member for connecting said actuator to each of said closure assemblies, wherein movement of said connecting member engages said contact closure assemblies.