Electrical switching device with blow-out channels for arc gases

• US 5,811,749 A
• Filed: 10/18/1996
• Issued: 09/22/1998
• Est. Priority Date: 04/20/1994
• Status: Expired due to Term

• Current Assignee: Moeller GmbH (Eaton Corporation PLC.)
• Original Assignee: Klockner-Moeller GmbH
• Inventors: Bausch, Christoph, Boder, Franz, Howald, Bernd
• Primary Examiner(s): SCOTT, JAMES R
• Application Number:
  US08/734,628
• Time in Patent Office: 704 Days
• Field of Search: 200/304-306, 337/203, 337/250, 337/272, 337/328, 218/22-40, 218/154-158, 335/201, 335/202
• US Class Current: 218/157
• CPC Class Codes: H01H 1/5855 characterised by the use of a wire clamping screw or nut
• CPC Class Codes: H01H 2011/0093 Standardization, e.g. limiting the factory stock by limiting the number of unique, i.e. different components
• CPC Class Codes: H01H 71/0228 having provisions for interchangeable or replaceable parts
• CPC Class Codes: H01H 71/08 Terminals; Connections
• CPC Class Codes: H01H 9/0264 Protective covers for terminals
• CPC Class Codes: H01H 9/342 Venting arrangements for arc chutes
• CPC Class Codes: H01R 4/301 having means for preventing complete unscrewing of screw or nut

Abstract

An electrical switch is intended to prevent hot arc gases from contacting the terminal screw units. The arc gases are to flow off in an already deionized manner so that no damage is caused even when they flow out towards the electric cable terminals without the need for additional shielding for the terminals. A terminal cover section is designed with blow-out channels which are fully encapsulated with respect to the terminal screws and to the terminal chambers and have an outlet aperture each. To fully encapsulate and provide access to each of the terminal screws, a location dome passes through each blow-out channel. At the points where the through apertures join the quench chambers, the inserted terminal cover section is sealed against the separating wall of the housing in the region of the blow-out channel inlet apertures. The arc gases flow from arc quenching chambers through a partition by way of passage openings. The passage openings open into the blow-out channels, which blow-out channels are wider than the passage openings. Then the arc gases flow through a portion of the blow-out channels narrowed by the presence of the location domes passing through the blow-out channels. As the arc gases pass beyond the location domes, the blow-out channels widen as a result of the absence of the location domes.

Claims

1. An electrical switching device comprising:

a housing;

electrical switching components being disposed within said housing;

said housing comprising;

an arc quenching chamber to quench electrical arcs from said electrical switching components;

a terminal chamber to house electrical conductor connections;

a partition disposed between said arc quenching chamber and said terminal chamber;

said partition comprising a partition passage opening to discharge arc gases from said arc quenching chamber;

a terminal connecting unit to connect an electrical conductor to said electrical switching device;

said terminal connecting unit being disposed in said terminal chamber;

a terminal cover part to cover said terminal connecting unit;

said terminal cover part being a separate part from said housing; and

said terminal cover part comprising;

a through-hole to permit access to said terminal connecting unit to permit connection of an electrical conductor to said electrical switching device;

a blow-out channel to direct the flow of arc gases through said terminal chamber;

said blow-out channel comprising an outlet opening, an inlet opening, and a channel passage disposed between said inlet opening and said outlet opening;

said channel passage comprising an arrangement for completely encapsulating said channel passage with respect to said terminal connecting unit and with respect to said terminal chamber;

an arrangement for disposing said inlet opening tightly up against said partition; and

an arrangement for disposing said inlet opening around said partition passage opening.

2. The electrical switching device of claim 1, wherein:

said terminal connecting unit has a longitudinal axis;

said blow-out channel comprises a molded channel duct to direct the flow of arc gases through said terminal chamber;

said encapsulating arrangement comprises a location dome molded into said molded channel duct to form a hole penetrating said molded channel duct;

said hole penetrating said molded channel duct is said through-hole;

said location dome has a longitudinal axis substantially coaxial to the longitudinal axis of said terminal connecting unit;

said molded channel duct has an axis defined along the flow direction of arc gases; and

said location dome is disposed so that the longitudinal axis of said location dome is oriented substantially perpendicular to the axis along the flow path.

3. The electrical switching device of claim 2, wherein:

said location dome is disposed to divide said blow-out channel over a portion of said blow-out channel into two subchannels;

said blow-out channel has a first cross sectional area for the flow of arc gases;

said two subchannels have a combined cross sectional area for the flow of arc gases;

said combined cross sectional area of said two subchannels is a second cross sectional area; and

said first cross sectional area is greater than said second cross sectional area.

4. The electrical switching device of claim 3, wherein:

said terminal chamber has a depth;

said channel duct has a length; and

the length of said channel duct is substantially equal to the depth of said terminal chamber.

5. The electrical switching device of claim 4, wherein:

said terminal chamber has a top side disposed adjacent to said through-hole;

said terminal chamber has a front side disposed adjacent said outlet opening;

said terminal cover part comprises a roof side for covering said top side of said terminal chamber;

said roof side is disposed at a non-zero angle with respect to said top side of said terminal chamber;

said terminal cover part comprises a cover web attached to said roof side at a non-zero angle with respect to said roof side;

said cover web is disposed to at least partially cover said front side of said terminal chamber; and

said molded channel duct is molded onto said cover web.

6. The electrical switching device of claim 4 wherein:

said partition passage opening comprises a portion adjacent to said terminal connecting unit;

said partition comprises a sealing collar molded into said partition to seal against said inlet opening;

said sealing collar is disposed adjacent to said portion of said partition passage opening;

said sealing collar is dimensioned to extend into said terminal chamber;

said arrangement for disposing said inlet opening around said partition passage comprises a downward-pointing overhang disposed on said inlet opening; and

said downward-pointing overhang is dimensioned to fit on said sealing collar.

7. The electrical switching device of claim 4, wherein:

said electrical switching device comprises an arrangement for forming a labyrinth seal between said inlet opening and said partition; and

said labyrinth seal arrangement comprises at least one of;

grooves disposed at least in sections about said inlet opening; and

a sealing collar dimensioned to extend into said terminal chamber, said sealing collar being disposed at least in sections around said partition passage opening.

8. The electrical switching device of claim 3, wherein:

said electrical switching device comprises a blow-out damper to dampen flow of arc gas through said partition passage opening;

said blow-out damper is disposed adjacent to said partition passage opening to at least partially cover said partition passage opening;

said blow-out damper comprises at least one damper opening;

said partition passage opening has a cross-sectional area;

said at least one damper opening has a cross-sectional area;

the cross-sectional area of said damper opening is less than the cross-sectional area of said partition passage opening;

said blow-out channel has a cross-sectional area adjacent to said inlet opening;

the cross-sectional area adjacent said inlet opening is the first cross-sectional area of said blow-out channel; and

the first cross-sectional area is greater than the cross-sectional area of said damper opening.

9. The electrical switching device of claim 4, wherein:

said terminal cover part comprises an arrangement for being fastened to said housing by screws;

said fastening arrangement comprises a screw hole;

said screw hole comprises said arrangement for disposing said inlet opening tightly up against said partition upon the fastening of said terminal cover part to said housing; and

said arrangement for disposing said inlet opening tightly up against said partition comprises an application web disposed in said screw hole.

10. The electrical switching device of claim 1, wherein:

said terminal chamber has a top side disposed adjacent to said through-hole;

said terminal chamber has a front side disposed substantially perpendicular to said top side; and

said outlet opening is disposed at said front side.

11. The electrical switching device of claim 3, wherein:

said terminal chamber has a top side disposed adjacent to said through-hole;

said terminal chamber has a front side disposed substantially perpendicular to said top side; and

said outlet opening is disposed at said front side.

12. The electrical switching device of claim 1, wherein:

said terminal connecting unit comprises a terminal screw to connect an electrical conductor to said electrical switching device;

said through-hole is disposed coaxial to said terminal screw;

said blow-out channel comprises a molded channel duct to direct the flow of arc gases through said terminal chamber;

said encapsulating arrangement comprises a location dome molded into said molded channel duct to form a hole penetrating said molded channel duct;

said hole penetrating said molded channel duct is said through-hole;

said location dome has a longitudinal axis coaxial to said terminal screw;

said molded channel duct has an axis defined along the flow direction of arc gases;

said location dome is disposed so that the longitudinal axis of said location dome is oriented substantially perpendicular to the axis along the flow path;

said location dome is disposed to divide said blow-out channel over a portion of said blow-out channel into two subchannels;

said blow-out channel has a first cross sectional area for the flow of arc gases;

said two subchannels have a combined cross sectional area for the flow of arc gases;

said combined cross sectional area of said two subchannels is a second cross sectional area;

said first cross sectional area is greater than said second cross sectional area;

said terminal chamber has a depth;

said channel duct has a length;

the length of said channel duct is substantially equal to the depth of said terminal chamber;

said terminal chamber has a top side disposed adjacent to said through-hole;

said terminal chamber has a front side disposed adjacent said outlet opening;

said terminal cover part comprises a roof side for covering said top side of said terminal chamber;

said roof side is disposed at a non-zero angle with respect to said top side of said terminal chamber;

said terminal cover part comprises a cover web attached to said roof side at a non-zero angle with respect to said roof side;

said cover web is disposed to at least partially cover the front side of said terminal chamber;

said molded channel duct is molded onto said cover web;

said partition passage opening comprises a portion adjacent to said terminal connecting unit;

said partition comprises a sealing collar molded into said partition to seal against said inlet opening;

said sealing collar is disposed adjacent to said portion of said partition passage opening;

said sealing collar is dimensioned to extend into said terminal chamber;

said arrangement for disposing said inlet opening around said partition passage comprises a downward-pointing overhang disposed on said inlet opening;

said downward-pointing overhang is dimensioned to fit on said sealing collar;

said electrical switching device comprises an arrangement for forming a labyrinth seal between said inlet opening and said partition;

said labyrinth seal arrangement comprises at least one of;

grooves disposed at least in sections about said inlet opening; and

said sealing collar being disposed at least in sections around said partition passage opening;

said electrical switching device comprises a blow-out damper to dampen flow of arc gas through said partition passage opening;

said blow-out damper is disposed adjacent to said partition passage opening to at least partially cover said partition passage opening;

said blow-out damper comprises at least one damper opening;

said partition passage opening has a cross-sectional area;

said at least one damper opening has a cross-sectional area;

the cross-sectional area of said damper opening is less than the cross-sectional area of said partition passage opening;

said blow-out channel has a cross-sectional area adjacent to said inlet opening;

the cross-sectional area adjacent said inlet opening is the first cross-sectional area of said blow-out channel;

the first cross-sectional area is greater than the cross-sectional area of said damper opening;

said terminal cover part comprises an arrangement for being fastened to said housing by screws;

said fastening arrangement comprises a screw hole;

said screw hole comprises said arrangement for disposing said inlet opening tightly up against said partition upon the fastening of said terminal cover part to said housing;

said arrangement for disposing said inlet opening tightly up against said partition comprises an application web disposed in said screw hole;

said terminal chamber has a top side disposed adjacent to said through-hole;

said terminal chamber has a front side disposed substantially perpendicular to said top side;

said outlet opening is disposed at said front side;

said location dome comprises an arrangement for engaging a thread of said terminal screw to hold said terminal screw in said through-hole; and

said engaging arrangement comprises a projection projecting into said through-hole.

13. The electrical switching device of claim 1, wherein:

said terminal connecting unit comprises a terminal screw to connect an electrical conductor to said electrical switching device; and

said through-hole is disposed coaxial to said terminal screw.

14. The electrical switching device of claim 13 wherein:

said blow-out channel comprises a molded channel duct to direct the flow of arc gases through said terminal chamber;

said encapsulating arrangement comprises a location dome molded into said molded channel duct to form a hole penetrating said molded channel duct;

said hole penetrating said molded channel duct is said through-hole;

said location dome has a longitudinal axis coaxial to said terminal screw;

said molded channel duct has an axis defined along the flow direction of arc gases; and

said location dome is disposed so that the longitudinal axis of said location dome is oriented substantially perpendicular to the axis along the flow path.

15. The electrical switching device of claim 14, wherein:

said location dome is disposed to divide said blow-out channel over a portion of said blow-out channel into two subchannels;

said blow-out channel has a first cross sectional area for the flow of arc gases;

said two subchannels have a combined cross sectional area for the flow of arc gases;

said combined cross sectional area of said two subchannels is a second cross sectional area; and

said first cross sectional area is greater than said second cross sectional area.

16. The electrical switching device of claim 15, wherein:

said terminal chamber has a depth;

said channel duct has a length; and

the length of said channel duct is substantially equal to the depth of said terminal chamber.

17. The electrical switching device of claim 15, wherein:

said electrical switching device comprises a blow-out damper to dampen flow of arc gas through said partition passage opening;

said blow-out damper is disposed adjacent to said partition passage opening to at least partially cover said partition passage opening;

said blow-out damper comprises at least one damper opening;

said partition passage opening has a cross-sectional area;

said at least one damper opening has a cross-sectional area;

the cross-sectional area of said damper opening is less than the cross-sectional area of said partition passage opening;

said blow-out channel has a cross-sectional area adjacent to said inlet opening;

the cross-sectional area adjacent said inlet opening is the first cross-sectional area of said blow-out channel; and

the first cross-sectional area is greater than the cross-sectional area of said damper opening.

18. The electrical switching device of claim 15, wherein:

said location dome comprises an arrangement for engaging a thread of said terminal screw to hold said terminal screw in said through-hole; and

said engaging arrangement comprises a projection projecting into said through-hole.

19. The electrical switching device of claim 16, wherein:

said location dome comprises an arrangement for engaging a thread of said terminal screw to hold said terminal screw in said through-hole; and

said engaging arrangement comprises a projection projecting into said through-hole.

20. The electrical switching device of claim 17, wherein:

said location dome comprises an arrangement for engaging a thread of said terminal screw to hold said terminal screw in said through-hole; and

said engaging arrangement comprises a projection projecting into said through-hole.