Circuit Breaker Trigger Device with Dual Stop Surfaces
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Solution Overview
Problem
The existing trigger devices in circuit breakers, which use a simple push rod to disconnect moving contacts from fixed contacts during a short circuit, often result in contact bouncing, leading to erosion and damage, thereby shortening the lifespan of the contacts and the circuit breaker.
Innovation Solution
The trigger device incorporates at least two different stop surfaces, where one stop surface triggers the latch and another prevents the backward movement of the moving contact, ensuring safe disconnection without damage by preventing bouncing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple push rod is used to trigger the latch, then the device complexity is reduced, but the moving contact bounces back causing contact damage and shortened lifespan
Solution Approach 1:
The push rod is segmented into multiple functional surfaces: a first stop surface for triggering the latch and a second stop surface for preventing contact bounce. This segmentation allows each surface to perform its specific function independently, resolving the contradiction by adding functional complexity only where necessary while maintaining overall simplicity.
Solution Approach 2:
The push rod is designed as a multi-functional component that both triggers the latch mechanism and prevents contact bounce through its different stop surfaces. This multi-functionality eliminates the need for separate components, achieving reliability improvement without proportionally increasing device complexity.
2Speed
If the moving contact is allowed to move freely after disconnection, then the disconnection speed is improved, but the moving contact bounces back causing erosion and damage
Solution Approach 1:
The second stop surface on the push rod provides preliminary anti-action by positioning itself to prevent the moving contact from bouncing back toward the fixed contact. This pre-positioned constraint counteracts the harmful bounce motion before it can cause damage, while allowing the initial disconnection to proceed at high speed.
Solution Approach 2:
The push rod acts as an intermediary component between the latch mechanism and the moving contact. It mediates the disconnection process by first triggering the latch and then providing a physical barrier (second stop surface) to prevent harmful bounce, thus protecting the contacts without impeding the disconnection speed.
3Reliability
If a latch mechanism is used to disconnect contacts, then the disconnection reliability is improved, but the moving contact may still bounce back after disconnection
Solution Approach 1:
The trigger device merges two functions into a single integrated component: the latch triggering function and the contact bounce prevention function. The push rod combines both the first stop surface for latch engagement and the second stop surface for contact protection, eliminating the harmful bounce effect while maintaining disconnection reliability.
Solution Approach 2:
The push rod performs preliminary action by positioning the second stop surface in advance to intercept any potential bounce motion of the moving contact. This pre-positioned protective barrier ensures that even if the latch mechanism successfully disconnects the contacts, the moving contact cannot bounce back to cause damage.
Data Source
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AI summary
For a trigger device (1) for a circuit breaker (2) comprising a push rod (3) which is movably guided in a push rod housing (4) and a coil (5) which is substantially wrapped around said push rod housing (4), it is suggested, that the push rod (3) comprises at least two different stop surfaces (6, 8), whereby at least one first stop surface (6) is adapted to contact a latch (7) in order to trigger said latch (7) of the circuit breaker (2) and at least one second stop surface (8) is adapted to contact a moving contact (9) of the circuit breaker (2) to prevent a backward movement of the moving contact (9) in direction of a fixed contact (10).