Unitary Cut-off Block with Metal Deflector for Arc Control
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Solution Overview
Problem
In contactors used for controlling alternating currents, the arc formed during current interruption causes erosion of contact pads and reduces dielectric withstand, as magnetic forces can push the arc in the wrong direction, leading to increased erosion.
Innovation Solution
The cut-off unit incorporates a metal deflector and arc extinguishing chambers with insulating layers and gas-generating materials, which channel the arc into a U-shaped metal assembly, ensuring electrical continuity and preventing premature wear by directing the arc away from the contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic blowing U parts are used to control the arc, then the arc can be directed away from the contact zone, but the magnetic force may push the arc in the opposite direction causing strong erosion of the contact support
Solution Approach 1:
The patent introduces a metal deflector as an intermediary component between the magnetic blowing U and the contact support. This deflector intercepts and redirects the arc in a controlled manner, preventing the arc from directly eroding the contact support while maintaining the beneficial arc-direction effects of the magnetic blowing U.
Solution Approach 2:
The patent converts the potentially harmful strong magnetic force that could push the arc toward the contact support into a beneficial effect by using the metal deflector to redirect this force. The deflector transforms the harmful arc trajectory into a controlled path that maintains electrical continuity while protecting the contact support from erosion.
2Reliability
If the arc is not quickly cooled and expelled from the contact zone, then the dielectric withstand between contacts decreases, but allowing the arc to persist causes increased erosion of contact pads
Solution Approach 1:
The patent extracts the arc from the harmful contact zone by using the metal deflector and arc extinguishing chamber to redirect and contain the arc. This separation removes the arc from its damaging position while maintaining the necessary electrical continuity through the deflector, thereby protecting contact pads from erosion.
Solution Approach 2:
The patent converts the harmful persistent arc into a beneficial controlled phenomenon by channeling it through the metal deflector and into the arc extinguishing chamber. This transformation allows the arc to be contained and eventually extinguished in a controlled environment, protecting the contact pads while maintaining dielectric withstand.
3Reliability
If a complex arc control system is used to protect contacts, then contact erosion is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the metal deflector with the existing arc extinguishing chamber structure, integrating multiple arc control functions into a unified component. This consolidation provides effective arc protection while avoiding the complexity of separate, independent arc control systems.
Solution Approach 2:
The metal deflector serves multiple functions simultaneously: it maintains electrical continuity, redirects the arc away from the contact support, and works in conjunction with the arc extinguishing chamber. This multi-functionality reduces the need for additional specialized components, thereby simplifying the overall device structure.
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 design effectively extinguishes the arc, reducing contact erosion and enhancing dielectric withstand by directing the arc into a controlled cooling area, thus improving the efficiency and reliability of current interruption.
Implementation Method 1
an arc appears at the level of the contacts. This arc necessary for breaking must be cooled and expelled quickly from the contact zone
Implementation Method 2
said side plates comprising an insulating layer on their inner face
Implementation Method 3
the two parallel side plates of an arc extinguishing chamber have interior surfaces covered with a gas generating material
Implementation Method 4
A rear wall connects the two side plates to form a U-shaped metal wall
Data Source
Figure 1~2
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Figure 7~8
AI summary
The invention concerns a unitary cut-off block (80) comprising electrical cut-off means (30) having at least one fixed contact (32), comprising an electrical contact zone (37), and a movable contact (33) with at least one end comprising a contact zone (36) which can cooperate with a contact zone (37) on a fixed contact (32). At least one arc-extinguishing chamber (24) comprises a metal wall consisting of two parallel lateral plates (68) and a rear wall (72) connecting the two lateral plates (68) so as to form a U-shaped metal wall. Each arc-extinguishing chamber (24) comprises a metal deflector (69) electrically connecting a fixed contact (32) to a rear wall (72) so as to ensure electrical continuity and form an upper part of the metal wall of the arc-extinguishing chamber.