Circuit Breaker Movable Contact Assembly Pressurizing Protrusion
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Solution Overview
Problem
Current circuit breakers with current limiting interruption mechanisms face challenges in preventing reinputting of movable contacts due to rebound phenomena, especially when not all contacts are simultaneously opened during current limiting events.
Innovation Solution
A movable contact assembly with a pressurizing protrusion at each movable contact finger that pushes a catch to prevent reinputting, even when only one contact is opened, utilizing a triangular-shaped protrusion with an inclined surface to effectively restrict the catch's operation and prevent reinputting during current limiting interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single catch is used to prevent reinputting of movable contacts, then the structure is simple, but it cannot effectively prevent reinputting when not all contacts are simultaneously opened during current limiting events
Solution Approach 1:
The single catch mechanism is segmented into multiple independent catch fingers (first catch finger, second catch finger, etc.), each capable of independently engaging with corresponding movable contacts. This segmentation allows each catch finger to independently prevent reinputting of individual movable contacts, solving the reliability issue while maintaining structural simplicity through modular design.
Solution Approach 2:
Instead of requiring all movable contacts to be simultaneously opened for the catch to function, the segmented catch mechanism enables partial action where individual catch fingers can engage individual movable contacts independently. This allows the system to prevent reinputting even when only some contacts are opened during current limiting events.
2Ease of operation
If movable contacts are allowed to pivot freely during current limiting interruption, then the operation is smooth, but rebound phenomenon causes reinputting of contacts
Solution Approach 1:
The catch fingers are positioned and configured to preemptively counteract the rebound phenomenon before it can cause reinputting. When movable contacts pivot during current limiting interruption, the catch fingers are already in position to engage and restrict further pivoting, providing preliminary anti-action that prevents the harmful rebound effect while allowing normal operational pivoting.
Data Source
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AI summary
Disclosed herein is a movable contact assembly for a circuit breaker, and more particularly, a movable contact assembly for a circuit breaker in which a pressurizing protrusion for pushing a catch is provided at each of movable contact fingers and thus, when current limiting interruption occurs in any one of the movable contact fingers, reinputting of the movable contact fingers is prevented such that blocking thereof is stably kept. According to an aspect of the present invention, there is provided a movable contact assembly for a circuit breaker, which includes a fixed contact, a connector formed to protrude from one side of a terminal connected to a load or a power source, a plurality of movable contacts pivotably installed at the connector through a connector pin and configured to be contactable to or separable from the fixed contact, a side holder pivotably installed at the connector through the connector pin, a catch pivotably installed at the connector, supported on the side holder, and configured to restrict a rebound phenomenon of the plurality of movable contacts when current limiting interruption occurs, and a pressurizing protrusion formed at a lower portion of each of the plurality of movable contacts and configured to push the catch when the current limiting interruption occurs.