Magnetic Assembly for Circuit Breaker Contact Force
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Solution Overview
Problem
In circuit interrupting systems, high fault currents lead to excessively high blow-off forces, necessitating strong contact springs and large mechanisms, which increase size, cost, and complexity in vacuum switches and circuit breakers.
Innovation Solution
The use of electromagnetic assemblies that harness fault current to generate either repulsive or attractive magnetic forces, allowing for the reduction or elimination of contact springs by creating a blow-on force to counteract blow-off forces, utilizing moving and stationary coils with current transfer straps or electromagnets and magnetic cores to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong contact springs and large mechanisms are used to counterbalance blow-off force, then contact connection reliability is improved, but device size and complexity increase
Solution Approach 1:
The patent replaces the traditional mechanical contact spring system with an electromagnetic system. Electromagnetic assemblies generate magnetic forces that act on the contacts during fault conditions, eliminating the need for strong mechanical contact springs and complex mechanisms while maintaining contact connection reliability.
Solution Approach 2:
The patent converts the harmful blow-off force generated by fault current into a beneficial effect. By using the same fault current to generate magnetic forces through electromagnetic assemblies, the system transforms the problematic electromagnetic force into a useful contact force that maintains contact connection during fault conditions.
2Reliability
If strong contact springs are used to counterbalance blow-off force, then contact integrity is maintained, but device size increases
Solution Approach 1:
The patent replaces bulky mechanical contact springs with compact electromagnetic assemblies. These assemblies generate the necessary magnetic forces in-situ, eliminating the need for large mechanical components while maintaining contact integrity during fault conditions.
Solution Approach 2:
The electromagnetic assemblies utilize the fault current itself to generate the counterbalancing magnetic forces. This self-service approach eliminates the need for separate power sources or large mechanical spring systems, reducing device size while maintaining contact integrity.
3Reliability
If large mechanisms are used to counterbalance blow-off force, then contact connection is maintained, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, precision-machined mechanical mechanisms with electromagnetic assemblies that can be manufactured using standard electromagnetic component fabrication processes. This substitution reduces manufacturing complexity and cost while maintaining contact connection reliability.
Solution Approach 2:
By using the fault current to generate the counterbalancing magnetic forces, the patent eliminates the need for oversized mechanical components, reducing material costs, manufacturing complexity, and overall device cost while maintaining contact connection during fault conditions.
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
This approach allows for a smaller, cheaper, and less complex mechanism in vacuum switches and circuit breakers, effectively balancing blow-off forces without the need for large contact springs, thereby reducing size and cost while maintaining contact integrity.
Implementation Method 1
The moving coil and stationary coil are positioned such that current flow through the first moving coil arc section and the first stationary coil arc section generates a force that pushes the moving coil away from the stationary coil and the moving stem of the moving contact toward the stationary contact
Implementation Method 2
a first magnetic core shaped to fit around a first section of the coil conductor, wherein the first magnetic core is configured, when current flows through the coil conductor to the first auxiliary conductor, to become magnetized
Implementation Method 3
attract the plunger in an axial direction toward the magnetic core
Data Source
AI summary
A magnetic module in a circuit interrupting system is configured to generate a blow-on force that pushes a moving contact toward a stationary contact. The magnetic module includes: a coil conductor having an opening through which a moving stem of the moving contact may move, wherein the coil conductor is electrically connected to the moving stem and a first auxiliary conductor, wherein the coil conductor is configured to allow current to flow from the moving stem to the first auxiliary conductor; a plunger attached to an end of the moving stem; and a first magnetic core shaped to fit around a first section of the coil conductor, wherein the first magnetic core is configured, when current flows through the coil conductor to the first auxiliary conductor, to become magnetized, attract the plunger toward the magnetic core, and cause the moving stem of the moving contact to move toward the stationary contact.