Integrated Thomson Coil Conductor Assembly for Fast Contact Opening
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Solution Overview
Problem
Existing circuit interrupters face challenges in opening mechanical separable contacts at high speeds, leading to potential arcing and increased let-through current during fault conditions, as current actuators are not capable of rapid enough separation.
Innovation Solution
An improved Thomson coil actuator assembly is integrated into both the stationary and movable conductor assemblies, featuring a cup-shaped conductive member with a bi-layer structure and cutouts, reducing mass and enabling faster separation of contacts by distributing force more efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional actuators are used to open mechanical separable contacts, then the device complexity is lower, but the opening speed is insufficient leading to increased let-through current during fault conditions
Solution Approach 1:
The Thomson coil assembly is nested within the movable conductor assembly, with the coil housed inside the cup-shaped conductive member that is coupled to the movable conductor. This nested arrangement allows the actuator components to be compactly integrated without increasing the overall footprint, achieving high opening speed while maintaining manageable device complexity
Solution Approach 2:
The patent replaces traditional mechanical actuation systems with an electromagnetic Thomson coil actuator. The coil generates a magnetic field that interacts with the conductive member to produce rapid mechanical motion, enabling opening speeds exceeding 1000 feet per second and significantly reducing let-through current during fault conditions
2Speed
If the movable conductor assembly mass is reduced to increase opening speed, then the opening speed improves, but the structural strength and durability may be compromised
Solution Approach 1:
The cup-shaped conductive member is constructed as a bi-layer composite structure with an inner layer of copper or copper alloy providing electromagnetic functionality and an outer layer of aluminum or aluminum alloy providing lightweight structural support. This composite construction reduces the overall mass of the movable conductor assembly while maintaining both structural integrity and electrical conductivity
Solution Approach 2:
The bi-layer structure applies different materials to different portions of the cup-shaped member: the inner surface facing the coil uses highly conductive copper for optimal electromagnetic interaction, while the outer structure uses lightweight aluminum to reduce mass. This local differentiation optimizes both speed and strength where needed
3Reliability
If a solid cup-shaped conductive member is used for the Thomson coil actuator, then the electromagnetic effectiveness is improved, but the mass of the movable conductor assembly increases
Solution Approach 1:
The cup-shaped conductive member incorporates a porous or lattice-like internal structure that maintains the electromagnetic effectiveness of the Thomson coil actuator while significantly reducing the mass of the movable conductor assembly. The porous structure provides sufficient conductive material for magnetic field interaction while minimizing overall weight
Solution Approach 2:
The bi-layer composite construction with copper inner layer and aluminum outer layer optimizes the balance between electromagnetic effectiveness and mass. The copper layer ensures adequate conductivity for reliable Thomson coil operation, while the aluminum layer provides lightweight structural support, achieving both reliability and weight reduction
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 improved actuator achieves faster opening times, reducing the initial gap between contacts and minimizing let-through current during fault conditions, with a potential 10% reduction in movable conductor assembly mass and up to 2 inches less vertical space usage in a pole assembly.
Implementation Method 1
a coil structured to remain fixed in place and a cup-shaped conductive member structured to be repelled by the coil when a current is supplied to the coil
Implementation Method 2
a cup-shaped conductive member formed as a bi-layer structure... structured to be repelled by the coil when a current is supplied to the coil
Data Source
AI summary
An actuator for opening the separable contacts of a circuit interrupter integrates a Thomson coil arrangement into the movable and stationary conductor assemblies. A movable separable contact is coupled to one end of the movable conductor, and a stationary separable contact is coupled to one end of the stationary conductor. The movable and stationary conductors are each formed with a collar positioned near the respective movable and stationary separable contacts. The actuator further includes a coil seated within a coil housing, and the coil housing is coupled to the stationary conductor collar. A conductive member shaped as a cup and structured to be actuated by the coil is coupled to the movable conductor collar, such that the rim of the cup faces the coil. A housing is positioned around the conductive member cup body with bellows and coupled to the coil housing, forming a vacuum chamber around the separable contacts.