Floating Contact Assembly for Circuit Breaker Arcing
Solution Overview
Problem
Circuit breakers experience arcing and contact damage when moving and stationary contacts engage and disengage, leading to reduced lifespan and imperfect electrical connections due to imperfections and arcing-related damage.
Innovation Solution
A floating contact assembly that self-adjusts by rotating about one or more axes, concentrating arcing damage to the top halves of the contacts during engagement and disengagement, maintaining the bottom halves for low resistance electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moveable and stationary contacts are brought into physical contact when circuit breaker is turned ON, then electrical connection is established, but arcing occurs which damages contacts and reduces circuit breaker lifespan
Solution Approach 1:
The stationary contact is made floatable rather than fixed, allowing it to dynamically adjust its position and orientation during engagement. The contact assembly can rotate about horizontal and vertical axes to self-align with the moveable contact, optimizing the contact geometry during both engagement and disengagement phases to minimize arcing damage.
Solution Approach 2:
The floatable contact assembly is pre-positioned and pre-oriented before engagement with the moveable contact. By allowing preliminary adjustment through rotation about horizontal and vertical axes, the contact surfaces are optimally aligned before electrical connection is established, reducing the intensity and duration of arcing during engagement.
2Reliability
If planar engagement between contact surfaces is established, then electrical connection is made, but imperfections and arcing damage prevent consistent low resistance connection
Solution Approach 1:
The floatable contact assembly dynamically adjusts its orientation during engagement by rotating about horizontal and vertical axes. This dynamic adjustment compensates for manufacturing imperfections in the contact surfaces, ensuring that the optimal contact geometry is achieved regardless of initial surface irregularities, thereby maintaining consistent low resistance electrical connection.
3Object-affected harmful factors
If contacts engage from a single point, then engagement is simple, but arcing damage occurs across the entire contact surface
Solution Approach 1:
The floatable contact assembly rotates about horizontal and vertical axes during engagement to control the contact progression. This dynamic movement concentrates arcing damage to specific regions (such as the leading edge or top portion of the contact) while preserving other regions (such as the bottom portion) for maintaining low resistance electrical connection, effectively managing damage distribution without complex additional mechanisms.
Data Source
AI summary
A floating contact assembly for use in a circuit breaker includes a contact, a floating member, a bearing element, a jaw member, and a flexible conductor. The floating member includes a joint surface and the contact is electrically connected to a surface of the floating member opposite the joint surface. The bearing element is configured to abut the joint surface of the floating member such that the floating member is configured to rotate about a first axis that passes through the bearing element. The jaw member is configured to electrically connect the floating contact assembly to an external electrical component and the flexible conductor electrically couples the jaw member to the floating member.