Shunt Tab Assembly With Spring Bias for Dielectric Clearance
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Solution Overview
Problem
Existing electrical switching apparatus, such as circuit breakers, face dielectric issues due to limited space and close proximity of electrically conductive components, and the machining of shunt tabs for mounting screws and bolts is costly and prone to mechanical weakness.
Innovation Solution
A shunt tab assembly with a leaf spring biasing element and a fastener system that includes a mounting bolt and nut retained within a cavity of the shunt tab, eliminating the need for external mounting screws and providing a stronger, dielectrically compliant connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mounting screws and bolts are used to fasten shunt tabs to the circuit breaker housing, then mechanical connection is achieved, but dielectric issues arise due to close proximity of electrically conductive components
Solution Approach 1:
The patent removes mounting screws and bolts from the assembly by integrating the shunt tab directly to the circuit breaker housing through rigid structural attachment. This eliminates the conductive fasteners that caused dielectric interference while maintaining strong mechanical connection between the shunt tab and housing.
2Ease of manufacture
If shunt tabs are machined with threaded holes to receive mounting screws, then mechanical attachment is enabled, but manufacturing cost increases and thread damage susceptibility increases
Solution Approach 1:
The patent eliminates threaded holes and mounting screws by using rigid structural attachment methods. The shunt tab is directly integrated to the housing through structural features such as tabs, slots, or direct molding, removing the vulnerable threaded connection entirely while simplifying manufacturing processes.
3Volume of moving object
If limited space is available in the circuit breaker housing, then compact design is achieved, but dielectric clearance between conductive components is reduced
Solution Approach 1:
The patent removes extraneous conductive fasteners (screws and bolts) from the assembly, eliminating the need for additional dielectric clearance around these components. The direct integration of the shunt tab to the housing reduces the number of discrete conductive parts, allowing adequate dielectric clearance to be maintained even in compact housing designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances mechanical connection strength and addresses dielectric issues by eliminating the need for threaded conductive components, ensuring a stable and efficient electrical connection while meeting dielectric testing criteria.
Implementation Method 1
a biasing element structured to bias the shunt tab toward a predetermined position with respect to the housing
Data Source
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AI summary
A shunt tab assembly is for an electrical switching apparatus, such as a circuit breaker. The electrical switching apparatus includes a housing, separable contacts enclosed by the housing, an operating mechanism for opening and closing the separable contacts, and a number of shunts. The operating mechanism includes a trip unit. The shunt tab assembly includes a shunt tab structured to be electrically connected to the shunts, a biasing element structured to bias the shunt tab toward a predetermined position with respect to the housing, and a fastener structured to mechanically couple and electrically connect the trip unit to the shunt tab.