Arc Extinguishing Device Insulating Coating for Circuit Breaker
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Solution Overview
Problem
Conventional arc extinguishing devices in circuit breakers for manual motor starters face challenges in swiftly extinguishing high-pressure and high-temperature arcs generated during fault current interruptions, leading to residual arcs that delay interruption times, cause thermal deformation, and reduce short-circuit interruption capacity, and are prone to assembly errors.
Innovation Solution
An arc extinguishing device with a detector and open/close mechanism, featuring a magnetic arc chamber and a conductive lower plate, coupled with insulation members at the distal ends of stationary contact bars to interrupt arcs externally, preventing residual arcs and thermal deformation, and ensuring correct assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional arc extinguishing devices with magnetic plates are used, then arcs can be induced into the arc chamber, but residual arcs still occur between distal ends of contact bars causing delayed interruption
Solution Approach 1:
The patent extracts the distal ends of the stationary and movable contact bars from the conductive path by coating them with insulating material. This removes the ability of these ends to conduct arc currents, thereby eliminating residual arcs that would otherwise persist after main arc extinction and causing delayed interruption.
Solution Approach 2:
The patent introduces an insulating coating as an intermediary layer between the contact bar surfaces and the arc plasma. This intermediate insulating layer prevents arc attachment and propagation at the distal ends, blocking the harmful residual arc paths without interfering with the normal arc extinction process in the arc chamber.
2Reliability
If conventional arc extinguishing devices are used, then arc induction is achieved, but thermal deformation occurs reducing short-circuit interruption capacity
Solution Approach 1:
The patent removes the vulnerable distal ends from the arc path by applying insulating coatings, extracting them from the high-temperature arc environment. This prevents these regions from experiencing thermal deformation that would reduce the circuit breaker's short-circuit interruption capacity.
Solution Approach 2:
The insulating coating is applied beforehand to the distal ends of contact bars, providing prior protection against thermal damage. This preventive measure cushions the contact bar surfaces from direct arc exposure and associated thermal deformation before the fault condition occurs.
3Ease of manufacture
If simple arc chamber structure is used, then manufacturing is easier, but assembly errors occur reducing arc interruption performance
Solution Approach 1:
The patent employs asymmetric positioning features and directional coating applications on the contact bars and arc chamber components. These asymmetric design elements provide built-in assembly guidance that prevents incorrect installation orientations, ensuring that components are assembled in the correct configuration for optimal arc interruption performance.
Solution Approach 2:
The patent uses visually distinct insulating coatings (different colors or appearances) on specific components to provide assembly guidance. These visual indicators help assembly workers correctly identify and position components, preventing assembly errors that would compromise arc interruption performance while maintaining simple manufacturing processes.
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 effectively reduces interruption time, enhances arc extinguishing performance, increases short-circuit interruption capacity, and prevents damage to circuit breakers and motors by blocking residual arcs and preventing thermal deformation, while also addressing assembly-related issues.
Implementation Method 1
Each magnetic plate (52) may have a U-shaped member opened in the direction of arc generation, and induce the arc (a) in response to the electromagnetic force.
Implementation Method 2
the arc (a) is extinguished by cathode effect and cooling effect of the magnetic plates (52) to finally interrupt the flow of the fault current
Implementation Method 3
the arc (a) is extinguished by cathode effect and cooling effect of the magnetic plates (52)
Data Source
AI summary
Disclosed is an arc extinguishing device of circuit breaker for manual motor starter capable of swiftly extinguishing and discharging an arc generated by a fault current flowing into a motor circuit during an interruption operation of a circuit breaker, thereby enhancing the performance of interruption.