Arrangement for arc transfer in high amperage molded case circuit breaker

• US 4,490,593 A
• Filed: 05/09/1983
• Issued: 12/25/1984
• Est. Priority Date: 05/09/1983
• Status: Expired due to Term

• Current Assignee: Square D Company (Schneider Electric SE)
• Original Assignee: Square D Company (Schneider Electric SE)
• Inventors: Cook, James W.
• Primary Examiner(s): Macon, Robert S.
• Application Number:
  US06/493,116
• Time in Patent Office: 596 Days
• Field of Search: 200/144 R, 200/147 R, 200/146 R
• US Class Current: 218/152
• CPC Class Codes: H01H 1/226 having a plurality of parallel contact bars
• CPC Class Codes: H01H 1/5833 comprising an articulating, sliding or rolling contact between movable contact and terminal
• CPC Class Codes: H01H 9/38 Auxiliary contacts on to which the arc is transferred from the main contacts using arcing-horns H01H9/46
• CPC Class Codes: H01H 9/46 using arcing horns using blow-out magnet H01H9/44

Abstract

Arc control in a high amperage molded case circuit breaker is provided by a steel horn for each of a plurality of contact blades for each phase. The horn has a portion extending into a U-shaped recess in a steel arc runner plate. As the contacts separate, the portion travels close to one wall of the recess and then close to the other wall to transfer the arc from the contacts first to the one wall and then to the other wall which is located adjacent the arc suppressor assembly. A respective adjustment member extending through each horn controls the spacing between the blades and a contact carrier to in turn control the opening sequence of the contacts for minimizing arcing across certain contacts. Arc suppressor plates of alternating length are arranged in an arc corresponding to blade travel and define passageways having their larger exits aligned with respective vents defined by a molded insulator engaged in the wall of the base.

Claims

1. In a multiphase molded case circuit breaker including a plurality of contact blades for each phase arranged to carry alternating current in a selected range between 800 and 3000 amperes, with each blade carrying a blade contact intermediate the ends of the respective blade and having a respective carrier for each phase adapted to pivot a free end of the respective blades in one direction about a blade pivot axis for engaging a respective stationary contact to establish a connection between a line conductor and a load conductor for each phase with each contact adapted to generate an arc in response to pivot movement of the respective carrier and the respective blades in the opposite direction during current interruption under the influence of respective overtravel springs located between each carrier and the respective blades, the improvement comprising:

bar means on each blade adjacent the free end of each blade and having a bar portion overlapping the respective blade,

a carrier portion on each carrier located between each respective bar portion and the respective blades,

and a respective adjustment member adjustably passing through each bar portion overlapping the respective blade for engagement by the respective carrier portion in response to pivoting of the respective carrier a respective predetermined distance in said opposite direction whereafter the respective adjustment member and bar means are pivoted in said opposite direction to pivot the respective blade in said opposite direction for separating the respective blade contact from the respective stationary contact whereby the adjustment of each member controls the sequence in which the respective contacts of each phase open relative the other contacts of the respective phase to in turn select the last contacts to open and generate said arc during current interruption.

2. In the circuit breaker claimed in claim 1, a steel horn secured to each blade adjacent the free end of the respective blade and having a first portion located between the respective blade and a respective conductor in response to the pivoting of the respective carrier for engaging a respective blade contact with a respective stationary contact for protecting the respective blade against the effects of an arc generated on movement of said blades in said opposite direction to separate the respective blade and stationary contacts during a fault current.

3. In the circuit breaker claimed in claim 2, a bar portion on each horn overlapping the free end of the respective blade and extending toward said one conductor and transverse to a radial line from the pivot axis of the respective blade to the respective blade contact in engagement with a respective stationary contact,

a respective steel runner for each phase secured to a respective one conductor and having one end located adjacent each of the respective stationary contacts of the respective phase and overlapped by said steel horn first portion in response to the pivoting of the respective carrier in said one direction for engaging each of the respective blade contacts with a respective stationary contact.

4. The circuit breaker claimed in claim 3 in which said runner has a U-shaped recess formed intermediate the ends of said steel runner for receiving the bar portion of each horn extending transverse to said radial line in spaced apart relationship to the walls of said recess during the engagement of the respective blade contact with the respective stationary contact,

each said bar portion extending into said recess passing adjacent one wall of said recess in response to movement of the respective blade in said other direction for disengaging the respective blade contact from a respective stationary contact during current interruption whereby an arc current is forced to transfer from a respective one of said blade contacts to said bar portion and one wall in response to the increasing separation of the contacts while the respective bar portion moves toward said radial line.

5. The improvement claimed in claim 4 in which each bar portion thereafter moves relatively close to the other wall of said recess in response to further pivoting movement of said blades in said other direction for transferring an arc to said other wall and in a direction from the free ends of said blades.

6. In a multiphase molded case circuit breaker including a plurality of contact blades for each phase arranged to pass alternating current in a selected range between 800 and 3000 amperes, with each blade carrying a blade contact intermediate the ends of the respective blade and havng a respective carrier for each phase adapted to pivot a free end of the respective blades in one direction about a blade pivot axis for engaging a respective stationary contact carried on one conductor to establish a connection between a line conductor and a load conductor for each phase in response to the erection of a toggle assembly adapted to be held erect by a latch assembly released in response to a fault current for enabling collapse of said toggle assembly to pivot each carrier and the respective blades in the opposite direction under the influence of respective overtravel springs located between each carrier and the respective blades, the improvment comprising:

a steel horn secured to each blade adjacent the free end of the respective blade and having a first portion located between the respective blade and a respective conductor in response to the pivoting of the respective carrier for engaging a respective blade contact with a respective stationary contact for protecting the respective blade against the effects of an arc generated on movement of said blades in said opposite direction to separate the respective blade and stationary contacts during a fault current,

a bar portion on each horn overlapping the free end of the respective blade and extending toward said one conductor and transverse to a radial line from the pivot axis of the respective blade to the respective blade contact in engagement with a respective stationary contact,

and a respective steel runner for each phase secured to a respective one conductor and having one end located adjacent each of the respective stationary contacts of the respective phase and overlapped by said steel horn first portion in response to the pivoting of the respective carrier in said one direction for engaging each of the respective blade contacts with a respective stationary contact, said runner having a U-shaped recess formed intermediate the ends of said steel runner for receiving the bar portion of each horn extending transverse to said radial line in spaced apart relationship to the walls of said recess during the engagement of the respective blade contact with the respective stationary contact,

each said bar portion extending into said recess passing adjacent one wall of said recess in response to movement of the respective blade in said other direction for disengaging the respective blade contact from a respective stationary contact during current interruption whereby an arc current is forced to transfer from a respective one of said blade contacts to said bar portion and one wall in response to the increasing separation of the contacts while the respective bar portion moves toward said radial line.

7. The improvement claimed in claim 6, in which each bar portion thereafter moves relatively close to the other wall of said recess in response to further pivoting movement of said blades in said other direction for transferring an arc to said other wall and in a direction from the free ends of said blades.

8. In the circuit breaker claimed in claim 6, bar means secured to each blade adjacent the free end of each blade and having a bar portion overlapping the respective blade,

a portion on each carrier located between each bar portion and the respective blades,

and a respective adjustment member adjustably passing through each bar portion overlapping the respective blade for engagement by said carrier portion in response to pivoting of the respective carrier a respective predetermined distance in said opposite direction whereafter the respective adjustment member and means are pivoted in said opposite direction to pivot the respective blade in said opposite direction for opening the respective contacts whereby the adjustment of each member controls the sequence in which the respective contacts of each phase open relative the other contacts of the respective phase to in turn select the last contacts to open and generate said arc during current interruption.

9. In the circuit breaker claimed in claim 6 an arc stack for each phase comprising a plurality of spaced apart arc runner plates define stacked arc runner passageways extending transverse to the path of the free ends of said blades and having openings adjacent the free ends of the respective blades and widened openings spaced from the free ends of said blades.

10. The improvement claimed in claim 9 in which alternate ones of said plates have a leading edge spaced closer to the respective free ends than the immediately adjacent plate.

11. The improvement claimed in claim 10 in which the leading edge of the alternate ones of said plates are arranged in an arc generally parallel to the path of said free ends.

12. The improvement claimed in claim 6, in which each bar portion thereafter moves relatively close to the other wall of said recess in response to further pivoting movement of said blades in said other direction for transferring an arc to said other wall and in a direction from the free ends of said blades.

13. In a multiphase molded case circuit breaker adapted to carry alternating current in ranges between 800 and 3000 amperes, the improvement comprising:

a plurality of contact blades for each phase with each blade carrying a blade contact intermediate the ends of the respective blade,

a respective blade carrier for each phase overlapping the contact blades of the respective phase with each carrier adapted to move a respective plurality of blades in one direction

a line conductor and a load conductor for each phase,

a plurality of stationary contacts on one conductor of each phase with each stationary contact adapted to be engaged by a respective one of said blade contacts in response to pivoting movement of the respective blade in one direction and adapted to be disengaged from the respective blade contact in response to pivoting movement of the respective blade in another direction,

means pivotally supporting each carrier and the respective blades adjacent one end of each carrier and the respective blades,

means interconnecting each carrier for simultaneous movement of each carrier,

an overtravel spring for each blade interposed between the respective contact carrier and the respective blade for biasing the respective blade contact into engagement with a respective stationary contact in response to the respective carrier being moved in said one direction to a respective predetermined position and adapted to thereafter bias the respective carrier from said position for movement in the opposite direction in response to release of the carrier,

means adapted to move each carrier and blades with said blade contacts in said one direction and thereafter hold said carrier in the respective predetermined position,

means releasing each carrier in response to a selected condition to move in said opposite direction under the bias of said overtravel springs for moving the respective blades in said opposite direction after the respective carrier has moved said respective distance,

a respective steel runner for each phase secured to a respective one conductor and having one end located adjacent each of the respective stationary contacts of the respective phase and overlapped by said steel horn in response to the movement of the respective carrier for engaging the respective blade contacts with a respective stationary contact, said runner having a U-shaped recess formed intermediate the ends of said steel runner for receiving the portion of each bar extending past said one face of the respective blade in spaced apart relationship to the walls of said recess during the engagement of the respective blade contact with the respective stationary contact,

said other portion of said bar extending into said recess and adjacent but spaced from one wall of said recess in response to movement of the respective blade in said one direction for engaging the respective blade contact with a respective stationary contact for thereafter enabling an arc current to transfer from a respective one of said blade contacts to the respective horn and one wall in response to movement of said carrier and the respective blade in said other direction for disengaging said blade contact from said stationary contact and thereafter passing adjacent the other wall of said recess for establishing a high resistance path for said one arc current through said steel horn and said runner.

14. In a multiphase circuit breaker of the type adapted to carry currents in a range between 800 and 3000 amps and having a plurality of contact blades for each phase adapted to be pivoted into a position overlapping a respective conductor for engaging a blade contact on the blade with a contact on the respective conductor to extend an electrical circuit, the improvement comprising:

a steel horn secured to each blade adjacent the free end of the respective blade and having a first portion located between the respective blade and a respective conductor in response to the pivoting of the respective blade in one direction for engaging a respective blade contact with a respective stationary contact for protecting the respective blade against the effects of an arc generated on movement of said blade in the opposite direction to separate the respective blade and stationary contact during a fault current.

15. In the circuit breaker claimed in claim 14, a bar portion on each horn overlapping the free end of the respective blade and extending past opposite faces of the respective blade transverse to a radial line from the pivot axis of the respective blade to the respective blade contact in engagement with a respective stationary contact,

and a respective steel runner for each phase secured to a respective one conductor and having one end located adjacent each of the respective stationary conductor contacts of the respective phase and overlapped by said steel horn first portion in response to the pivoting of the respective blade in said one direction for engaging each of the respective blade contacts with a respective stationary contact, said runner having a U-shaped recess formed intermediate the ends of said steel runner for receiving the bar portion of each horn extending transverse to said radial line in spaced apart relationship to the walls of said recess during the engagement of the respective blade contact with the respective stationary contact,

each said bar portion extending into said recess passing adjacent one wall of said recess in response to movement of the respective blade in said other direction for disengaging the respective blade contact from a respective stationary contact during current interruption whereby an arc current is forced to transfer from a respective one of said blade contacts to said bar portion and one wall in response to the increasing separation of the contacts while the respective bar portion moves toward said radial line.

16. The improvement claimed in claim 15, in which each bar portion thereafter moves relatively close to the other wall of said recess in response to further pivoting movement of said blades in said other direction for transferring an arc to said other wall and in a direction from the free ends of said blades.