Electromagnetic Relay Venting Structure for Arc Re-Ignition Control
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Solution Overview
Problem
In electromagnetic relays, high-temperature gas generated by arcing can re-ignite due to poor insulation performance near the contacts, especially as load capacity increases, leading to contact melting and further arc generation.
Innovation Solution
The electromagnetic relay design includes a gas inflow space between the base and contact support portion, communicating with the outside through a gas passage, which efficiently directs high-temperature gas away from the contacts, preventing re-ignition by positioning the gas inflow space and passage near the fixed contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the gas passage inlet and outlet are disposed in the vicinity of the contacts, then the high-temperature gas can be directed away from the contacts, but the high-temperature gas easily returns to the contacts through the gas passage, increasing the risk of re-ignition
Solution Approach 1:
The gas passage is configured to extend in the depth direction of the case, creating a three-dimensional gas flow path that directs hot gas away from the contact area. The inlet is positioned at the bottom surface while the outlet opens at the side surface, utilizing spatial dimensionality to ensure hot gas is expelled from the vicinity of contacts rather than simply redirected within the same plane.
Solution Approach 2:
The gas passage is specifically positioned and oriented to create localized gas flow characteristics. The inlet is disposed at a specific location on the bottom surface, and the passage extends in a specific direction to ensure that the gas flow locally affects the contact area by directing hot gas away from it, while the outlet position ensures the gas is expelled from the critical zone.
2Object-affected harmful factors
If the gas passage is positioned near the contacts to efficiently escape high-temperature gas, then arc re-ignition is prevented, but the device complexity increases due to additional structural components
Solution Approach 1:
The gas passage is integrated directly into the case structure, combining the functions of the case body and the gas exhaust system into a single component. The case serves both as the protective enclosure and as the gas passage structure, eliminating the need for separate gas passage components and reducing overall device complexity.
Solution Approach 2:
The case structure is designed to serve multiple functions: it provides mechanical protection for the internal components, supports the contacts and terminals, and simultaneously acts as the gas passage for expelling hot gas. This multi-functionality reduces the total number of components needed in the device.
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 configuration effectively prevents re-ignition of arcs by ensuring high-temperature gas escapes outside the relay, maintaining insulation integrity and preventing contact damage.
Implementation Method 1
a gas passage that penetrates the base in the first direction and communicates the gas inflow space with an outside of the case... the high temperature gas arising from an arc generated between the first fixed contact and the first movable contact can be efficiently allowed to escape from the gas passage to the outside of the case
Data Source
AI summary
An electromagnetic relay includes a case including a base, a first fixed terminal held by the base, a movable contact piece, a gas inflow space, and a gas passage. The first fixed terminal includes a first fixed contact disposed apart from the base in a first direction inside the case, a contact support portion disposed between the first fixed contact and the base and configured to support the first fixed contact, and a first extending portion extending at an angle from the contact support portion and penetrating the base in the first direction. The movable contact piece includes a first movable contact facing the first fixed contact in the first direction. The gas inflow space is formed between the base and the contact support portion inside the case. The gas passage penetrates the base in the first direction and communicates the gas inflow space with an outside of the case.