Electromagnetic Relay Magnet Layout for Stable Arc Direction
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Solution Overview
Problem
Conventional electromagnetic relays face difficulties in controlling the extension direction of the arc due to significant changes in the direction of the Lorentz force acting on the arc, especially when the magnetic flux direction changes near the end of the magnet and when the arc extends in unintended directions.
Innovation Solution
The electromagnetic relay design includes a pair of magnets positioned to extend beyond the housing space in the direction parallel to the movable contact piece, ensuring a wider range of magnetic flux and minimizing changes in the Lorentz force direction, allowing for easier control of the arc extension direction by maintaining a consistent magnetic flux direction parallel to the contact piece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pair of magnets is arranged within the housing space, then the device size is reduced, but the magnetic flux direction changes significantly causing difficulty in controlling arc extension direction
Solution Approach 1:
The magnets are extended in the second direction (width direction) beyond the housing space boundaries, utilizing the lateral dimension to expand the magnetic flux coverage area. This dimensional extension ensures that the magnetic flux maintains a consistent parallel direction throughout the arc extension region, preventing significant directional changes that would occur with compact magnet arrangements.
2Ease of operation
If the magnets are extended beyond the housing space in the second direction, then the arc extension direction control is improved, but the device size increases
Solution Approach 1:
The magnetic field distribution is optimized locally by extending magnets only in the second direction (width direction) where it is most needed for arc control, while maintaining compact dimensions in the first direction (length direction). This selective extension provides the necessary magnetic flux coverage for stable arc extension direction control without excessive overall size increase.
3Stability of the object's composition
If the magnetic flux direction is maintained parallel to the contact piece, then the Lorentz force direction stability is improved, but the magnet arrangement complexity increases
Solution Approach 1:
The pair of magnets are positioned asymmetrically relative to the housing space, extending beyond the housing space boundaries in the second direction. This asymmetric arrangement creates a magnetic flux distribution that maintains parallel directionality along the contact piece length, ensuring stable Lorentz force direction without requiring complex additional magnetic components.
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 suppresses large changes in the Lorentz force direction, enabling precise control over the arc extension direction, even at positions separated from the contacts, by maintaining a consistent magnetic flux parallel to the contact piece, thus enhancing the reliability of the arc extinction process.
Implementation Method 1
The magnet portion generates a magnetic flux flowing in a direction parallel to the longitudinal direction between the fixed contact and the movable contact
Implementation Method 2
Lorentz force due to the magnetic force of the pair of magnets act on the arc generated at the contact, and the arc is extended toward an arc extinguishing space
Data Source
AI summary
An electromagnetic relay includes a pair of fixed terminals including a fixed contact, a movable contact piece, a housing portion, and a magnet portion. The movable contact piece includes a movable contact disposed facing the fixed contact. The movable contact piece is movable in a first direction in which the movable contact contacts the fixed contact and a second direction in which the movable contact separates from the fixed contact. The housing portion includes a housing space housing the fixed contact and movable contact piece. The magnet portion includes a pair of magnets disposed around the housing portion so as to face each other in a longitudinal direction of the movable contact piece and extending in the second direction beyond the housing space. The magnet portion generates a magnetic flux flowing in a direction parallel to the longitudinal direction between the fixed contact and the movable contact.