Electromagnetic Relay Magnet Layout for Arc Extension Control
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Solution Overview
Problem
Conventional electromagnetic relays face difficulties in controlling the direction of arc extension due to the direction of magnetic flux generated by permanent magnets, making it challenging to effectively utilize the arc extension space.
Innovation Solution
The electromagnetic relay design includes a housing with an arc extension space and a magnet configuration where the distance from the midpoint of the contact line to the base differs from the distance to the center of the arc extension space, allowing the magnetic flux to flow parallel to the contact and arc extension space, facilitating easier control of the arc direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single permanent magnet is used to generate magnetic field for arc guidance, then the structure is simple, but the arc extension direction cannot be controlled effectively
Solution Approach 1:
The single permanent magnet is divided into two separate magnet portions: a first magnet portion that generates magnetic flux to guide the arc from the contact toward the arc extension space, and a second magnet portion that generates magnetic flux to control the arc extension direction within the arc extension space. This segmentation allows independent control of different aspects of arc behavior, resolving the contradiction between structural simplicity and directional control capability.
2Stability of the object's composition
If the permanent magnet is positioned at the center, then the magnetic field distribution is symmetric, but the arc extension direction cannot be controlled when contacts are offset from center
Solution Approach 1:
The magnetic field distribution is made non-uniform by positioning the first and second magnet portions at different distances from the base. The first magnet portion is positioned closer to provide stronger magnetic flux for arc guidance from offset contacts, while the second magnet portion is positioned farther to control arc extension in the arc extension space. This local differentiation of magnetic field strength and direction enables effective arc control for offset contacts while maintaining overall system stability.
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 enables easier guidance and effective extension of the arc into the arc extension space, improving the control over the arc direction and its extension.
Implementation Method 1
The magnet is configured to generate a magnetic field to extend an arc generated between the fixed contact and the movable contact in the arc extension space
Implementation Method 2
the magnetic flux of the first magnet portion is to flow, near the contact, in a direction substantially parallel to the direction where the first magnet portion and the contact device overlap
Data Source
AI summary
An electromagnetic relay includes a base, a case, an arc extension space, a contact device, and a magnet. The contact device includes a fixed terminal, a fixed contact, a movable contact piece, a movable contact. The magnet includes a first magnet portion facing the contact device, and a second magnet portion disposed adjacent to the first magnet portion and facing the arc extension space. The magnet generates a magnetic field to extend an arc generated between the fixed contact and the movable contact. The base is separated from a midpoint of a straight line between the fixed contact and the movable contact by a distance different from a distance between the base and a center of the arc extension space. The base is separated from a center of the first magnet portion by a distance different from a distance between the base and a center of the second magnet portion.