Low tripping level circuit breakers, tripping units, and methods

Patent metadata

Field	Value
Publication number	US-9601296-B2
Application number	US-201313768014-A
Country	US
Kind code	B2
Filing date	Feb 15, 2013
Priority date	Apr 13, 2012
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

Embodiments provide a circuit breaker having a relatively low instantaneous current level at tripping. The circuit breaker includes a tripping mechanism coupled to a moveable electrical contact, the tripping mechanism including a tripping unit having a magnet, a bimetal member extending alongside of the magnet and having a moveable end, and an armature including an engagement portion being moveable as a result of motion the moveable end to trip the circuit breaker upon exceeding an instantaneous current level, and either the armature or the bimetal member includes a non-magnetic separating piece preventing a magnetic short circuit. System and method aspects are provided, as are other aspects.

First claim

What is claimed is:

1. A circuit breaker comprising
a housing containing a moveable electrical contact; and
a tripping mechanism coupled to a moveable electrical contact, the tripping mechanism including a tripping unit having
a magnet,
a bimetal member extending alongside of the magnet and including a moveable end, and
an armature including an engagement portion being moveable by motion of the moveable end of the bimetal member to trip the circuit breaker upon exceeding an instantaneous current level and wherein the tripping mechanism comprises a cradle having a triggering end engageable with a latching surface of the armature of the tripping unit, and an aperture formed in a body of the armature wherein the aperture is configured to receive the triggering end therein upon tripping, wherein: the armature or the bimetal member includes a non-magnetic separating piece preventing a magnetic short circuit between the moveable end and the armature.

2. The circuit breaker of claim 1 , wherein the non-magnetic separating piece comprises a spacer of a non-magnetic material provided on a surface of the bimetal member.

3. The circuit breaker of claim 2 , wherein the non-magnetic separating piece is provided between the engagement portion and a ferromagnetic side of the bimetal member.

4. The circuit breaker of claim 2 , wherein the non-magnetic separating piece is made of a material selected from a group of copper, brass, and aluminum.

5. The circuit breaker of claim 2 , wherein the non-magnetic separating piece is made of a plastic material.

6. The circuit breaker of claim 2 , wherein the non-magnetic separating piece is made of a piezoelectric material.

7. The circuit breaker of claim 2 , wherein the non-magnetic separating piece has a thickness of between about 0.127 mm and about 1.27 mm.

8. The circuit breaker of claim 1 , wherein the circuit breaker has a 15 A handle rating and trips at an instantaneous current level of less than about 120 A.

9. The circuit breaker of claim 8 , wherein the circuit breaker trips at an instantaneous current level of between about 120 A and about 180 A.

10. The circuit breaker of claim 1 , wherein the circuit breaker has a 20 A handle rating and trips at an instantaneous current level of less than about 160 A.

11. The circuit breaker of claim 10 , wherein the circuit breaker trips at an instantaneous current level of between about 160 A and about 200 A.

Assignees

• Yang Guang
• Siemens Industry Inc

Inventors

• Yang Guang

Classifications

• H01H71/16 Primary

  with bimetal element {(combined with detection of imbalance of two or more currents H01H83/223)} · CPC title

• H01H71/40

  Combined electrothermal and electromagnetic mechanisms · CPC title

• H01H71/323

  with rotatable armature · CPC title

• H01H71/164

  Heating elements · CPC title

• H01H77/04 Primary

  with electrothermal opening · CPC title