Finger Cluster Ground Connector With Low Rack-In Force
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Solution Overview
Problem
Existing heavy-duty connectors for medium voltage circuit breakers are costly to manufacture and undergo significant wear and tear due to high insertion and rack-in forces, often resulting in arc flash events during racking operations.
Innovation Solution
A finger cluster connector system comprising a conductive U-shaped body with leaf springs, designed to reduce insertion force and enhance durability by forming a constricted passage for sliding electrical contact with a rail conductor, allowing for repeated rack-in/out operations without excessive wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing heavy duty connector designs with multiple pieces (30-40 pieces) are used, then the connector can provide reliable grounding connection, but the manufacturing cost increases and assembly complexity increases
Solution Approach 1:
The patent combines multiple separate connector pieces (30-40 pieces in existing designs) into a single integrated conductor body formed from one piece of conductive material. This conductor body includes integrated fingers, springs, and contact elements that are unified into one component, reducing assembly complexity while maintaining grounding reliability through the integrated structure.
Solution Approach 2:
The single conductor body performs multiple functions simultaneously: it provides electrical conduction, mechanical spring pressure, finger segmentation for contact, and structural support. This multi-functional design eliminates the need for separate components while achieving the same reliable grounding connection.
2Reliability
If existing heavy duty connector designs are used, then the connector can handle grounding connections, but the insertion force and rack-in force become excessively high causing wear and tear
Solution Approach 1:
The conductor body is segmented into multiple fingers that can flex and deform independently. This segmentation allows the connector to distribute insertion forces across multiple flexible contact points rather than concentrating force on rigid structures, reducing peak forces during rack-in operations while maintaining reliable grounding.
Solution Approach 2:
The conductor body incorporates spring elements and flexible fingers that dynamically deform during insertion and rack-in operations. This dynamic flexibility allows the connector to absorb insertion forces through elastic deformation rather than transmitting full force to the mating contact, reducing wear and tear.
3Strength
If existing connector designs with high insertion forces are used, then the connector can provide heavy duty connection, but the wear and tear increases reducing operational lifespan
Solution Approach 1:
The conductor body is designed with pre-formed spring elements and flexible sections that act as cushioning mechanisms before contact. These elastic elements absorb and dissipate mechanical stresses from repeated rack-in operations, protecting the rigid structural components from wear and extending the connector's operational lifespan while maintaining connection strength.
4Ease of manufacture
If a single plate of conductive material is folded into U-shaped body with fingers, then the manufacturing cost decreases and assembly simplifies, but the insertion force may increase due to rigid structure
Solution Approach 1:
The single plate conductor is formed into a U-shaped body with integrated spring fingers that provide dynamic flexibility. This design maintains the manufacturing simplicity of a single-piece construction while incorporating elastic elements that deform during insertion, reducing peak insertion forces compared to a completely rigid single-piece structure.
Solution Approach 2:
The single conductor plate is segmented into multiple flexible fingers during forming. This segmentation creates multiple independent contact elements that can deform and flex during insertion, distributing and reducing insertion forces while maintaining the cost advantages of a single-piece manufacturing process.
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 finger cluster connector system is less costly to produce, reduces wear and tear, and can handle 1000 rack-in/out operations effectively, providing a reliable heavy-duty electrical connection for various applications.
Implementation Method 1
first and second leaf springs fastened to the conductor portion are divided into a plurality of spring finger sections with spring distal ends configured to respectively press against the distal ends of respective fingers of the conductor portion
Data Source
AI summary
A grounding system for a rackable circuit breaker includes a finger cluster connector connected to a grounding bus in the circuit breaker and a rail conductor mounted in a circuit breaker cradle and connected to ground potential. The finger cluster connector includes a conductor formed from a single plate of conductive material folded into a generally U-shaped body with first and second sides divided into a plurality of fingers. Distal ends of the fingers form mutually facing parallel surfaces of a constricted passage configured to make a sliding electrical contact with the rail conductor that is advanced into the constricted passage as the circuit breaker is racked into the cradle. First and second leaf springs fastened to the conductor portion are divided into a plurality of spring finger sections with spring distal ends configured to respectively press against the distal ends of respective fingers of the conductor portion.