Low voltage circuit breaker

Patent metadata

Field	Value
Publication number	US-11152179-B2
Application number	US-201815937011-A
Country	US
Kind code	B2
Filing date	Mar 27, 2018
Priority date	Mar 27, 2017
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

A low voltage circuit breaker is provided. The low voltage circuit breaker includes a contact system with a first contact and a second contact that are electrically connectable and disconnectable relative to one another. The first contact includes a body having a first layer and a second layer, wherein the first layer is arranged on the second layer and is configured to come in contact with the second contact for providing the electrical connection with the second contact. The first layer has a first material composition having an Ag content that is higher than an Ag content of a second material composition of the second layer. Further, the first material composition has a WC content that is lower than a WC content of the second material composition.

First claim

The invention claimed is:

1. A low voltage circuit breaker, comprising:
a contact system with a first contact and a second contact that are electrically connectable and disconnectable relative to one another,
wherein the first contact includes a body having a first layer and a second layer, wherein the first layer is arranged on the second layer and is positioned to contact with the second contact for providing the electrical connection with the second contact, the first layer and the second layer being on opposing ends of the body,
wherein the first layer has a first material composition having an Ag content that is higher than an Ag content of a second material composition of the second layer, and wherein the first material composition has a WC content that is lower than a WC content of the second material composition, the WC content increasing from the first end to the second end such that the WC content at the second end of the body is larger than the WC content in the remainder of the body,
wherein the body further includes a transition zone (tz) between the first layer and the second layer, wherein a WC content of the transition zone (tz) is gradually changed from the WC content of the first layer to the WC content of the second layer,
wherein the first layer has a WC/Ag content ratio equal to, or smaller than, 40/60, the composition of the first layer including, in mass-%, at least 25% W and at least 1.5% C, and
wherein the second layer has a WC/Ag content ratio equal to, or greater than, 60/40, the composition of the second layer including, in mass-%, at least 20% Ag.

2. A low voltage circuit breaker, comprising:
a first contact mounted to a carrier and extending between a first end and a second end of the body, the first end positioned to, via displacement of the carrier, contact a second contact of the low voltage circuit breaker, the body further comprising;
a first layer having a first composition along the first end that includes both an Ag content and a WC content, and
a second layer having a second composition along the second end that includes both an Ag content and a WC content,
wherein the Ag content of the first composition is greater, in mass-%, than the Ag content of the second composition, the second composition comprising, in mass-%, at least 20% Ag, and wherein the WC content of the second composition being larger, in mass-%, than the WC content of the first layer, the WC content increasing from the first end to the second end such that the WC content at the second end of the body is larger than the WC content in the remainder of the body, the first composition comprising, in mass-%, at least 26.5% WC, and
wherein the first contact has a first common conductivity based on a mean value of a first conductivity σ 1 of the first layer and a second conductivity σ 2 of the second layer, the first common conductivity of the first contact being different than a second common conductivity of the second contact.

3. A low voltage circuit breaker, comprising:
a contact system with a first contact and a second contact that are electrically connectable and disconnectable relative to one another,
wherein the first contact includes a body having a first layer and a second layer, wherein the first layer is arranged on the second layer and positioned to contact the second contact for providing the electrical connection with the second contact,
wherein the first layer has a first material composition having both an Ag content and a WC content, and the second layer having a second material composition having both an Ag content and an WC content, the Ag content of the first material composition being higher than the Ag content of the second material composition of the second layer, and wherein the WC content of the first material composition is lower than the WC content of the second material composition, the first layer and the second layer positioned on opposing first and second ends of the body, the WC content increasing from the first end to the second end such that the WC content at the second end of the body is larger than the WC content in the remainder of the body, and wherein the Ag content at the first end of the body where the first layer contacts the second contact is higher than the Ag content at the opposing second end of the body,
wherein the first material composition includes, in mass-%, Ag: 30 to 80, W: 25 to 65, Ni: 0 to 40, Co: 0 to 40, Cu: 0 to 40, C: 1.5 to 5, Cr: 0 to 20, Mo 0 to 20, the balance being Fe and inevitable impurities, wherein Ag, W, Ni, Co, Cu, C, Cr and Mo are included in a total amount of at least 80%, and wherein the second material composition comprises, in mass-%, Ag: 20 to 70.

4. The low voltage circuit breaker according to claim 3 , wherein the second material composition further includes, in mass-%, W: 35 to 75, Ni: 0 to 40, Cu: 0 to 40, C: 2 to 5.5, Cr: 0 to 20, Mo 0 to 20, the balance being Fe and inevitable impurities, wherein Ag, W, Ni, Co, Cu, C, Cr and Mo are included in a total amount of at least 80%.

5. The low voltage circuit breaker according to claim 3 , wherein the first layer has a first conductivity σ 1 that is higher than a second conductivity σ 2 of the second layer, the first contact having a first common conductivity based on a mean value of the first conductivity σ 1 and the second conductivity σ 2 , the first common conductivity of the first contact being different than a second common conductivity of the second contact.

6. The low voltage circuit breaker according to claim 5 , wherein the first conductivity σ 1 is equal to or greater than 10 MS/m, and/or the second conductivity σ 2 is equal to or greater than 5 MS/m.

7. The low voltage circuit breaker according to claim 5 , wherein the first conductivity σ 1 is equal to or smaller than 20 MS/m, and/or the second conductivity σ 2 is equal to or smaller than 20 MS/m.

8. The low voltage circuit breaker according to claim 3 , wherein the first layer has a first hardness H 1 that is smaller than a second hardness H 2 of the second layer, the first contact having a first common hardness based on a mean value of the first hardness H 1 and the second hardness H 2 , the first common hardness of the first contact being different than a second common hardness of the second contact.

9. The low voltage circuit breaker according to claim 8 , wherein the first hardness H 1 is equal to or greater than 130 HV1 and/or equal to or smaller than 200 HV1, and/or wherein the second hardness H 2 is equal to or greater than 150 HV1.

10. The low voltage circuit breaker according to claim 8 , wherein the second hardness H 2 is equal to or greater than 180 HV1 and/or equal to or smaller than 600 HV1.

11. The low voltage circuit breaker according to claim 3 , wherein the first layer has a first thickness (t l ) being equal to or greater than 3% of a body thickness (t b ) of the body (b).

12. The low voltage circuit breaker according to claim 3 , wherein the first layer and the second layer make up at least 80 mass-% of the body (b).

13. The low voltage circuit breaker according to claim 3 , wherein a rated number of switching operations of the low voltage circuit breaker at a rated nominal current is equal to or smaller than 20000.

14. The low voltage circuit breaker according to claim 3 , wherein the low voltage circuit breaker is rated for a voltage of equal to or greater than 100 V, and/or equal to or smaller than 1200 V.

15. The low voltage circuit breaker according to claim 3 , wherein the low voltage circuit breaker is rated for a current of equal to or greater than 10 A, specifically equal to or greater th

Assignees

• Abb Schweiz Ag

Inventors

• Schmoelzer Thomas
• Hoidis Markus
• Dell Oro Enrico
• Cantini Chiara
• Antoniazzi Antonello
• Simon Reinhard

Classifications

• C22C32/0052

  only carbides · CPC title

• C22C5/06 Primary

  Alloys based on silver · CPC title

• H01H1/0233

  and containing carbides · CPC title

• B22F7/02

  of composite layers {(B22F7/002 takes precedence)} · CPC title

• C22C29/08

  based on tungsten carbide · CPC title