Connection Unit Bus Bar Lorentz Force Contact Stability
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Solution Overview
Problem
In electromagnetic relays, the current tends to flow through the shortest path, resulting in an electromagnetic repulsive force that only generates at the ends of the movable contact, causing the contacts to come out of contact with each other.
Innovation Solution
A connection unit comprising an electromagnetic relay and a bus bar, where the bus bar is positioned to intersect the contact-making and breaking direction, with a gap between the bus bar and the movable touch piece, allowing the Lorentz force to generate a force that pushes the movable contacts against the fixed contacts, preventing them from disengaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If contact conductors have a C shape and an inverted C shape to generate electromagnetic repulsive force, then contact pressure between contacts is improved, but current flows only through the shortest path around both ends of the movable contact, causing the electromagnetic repulsive force to be generated only at the ends and potentially causing contacts to come out of contact
Solution Approach 1:
The bus bar is positioned outside the case in a different spatial dimension relative to the movable touch piece, with at least part of the bus bar lying over the movable touch piece in plan view. This dimensional arrangement creates additional current paths through portions of the bus bar and movable touch piece that lie over each other, generating electromagnetic repulsive force across the entire contact surface rather than only at the ends, thereby maintaining contact stability while ensuring reliable contact pressure.
2Power
If current flows through the shortest path, then electrical conductivity is improved, but the electromagnetic repulsive force is concentrated only at the ends of the movable contact, causing contacts to disengage
Solution Approach 1:
The bus bar is configured with different functional regions: portions connected to fixed contact terminals maintain short current paths for high conductivity, while portions that lie over the movable touch piece in plan view create extended current paths that generate electromagnetic repulsive force across the entire contact surface. This local differentiation allows the system to simultaneously achieve high electrical conductivity and reliable contact 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 ensures that the movable contacts remain in contact with the fixed contacts, enhancing contact pressure and preventing disengagement due to the electromagnetic repulsive force, thereby maintaining a stable connection.
Implementation Method 1
a force that is applied to the movable touch piece to push the movable contacts against the fixed contacts is generated by the Lorentz force
Implementation Method 2
an electromagnetic repulsive force generated by the Lorentz force caused by the current Ip flowing through each of the contact conductors 115 and the movable contact 130
Data Source
AI summary
Provided is a connection unit including an electromagnetic relay and a bus bar connected to the electromagnetic relay. In such a connection unit, a first bus bar connected to a first fixed contact terminal is disposed facing one surface of a movable touch piece located on an opposite side of the movable touch piece from the other surface of the movable touch piece in a contact-making and breaking direction, with a gap provided between the first bus bar and the movable touch piece in the contact-making and breaking direction, the first bus bar extends in a direction that intersects the contact-making and breaking direction and in which a first movable contact and a second movable contact of the movable touch piece are arranged, and at least part of the first bus bar lies over the movable touch piece in plan view in the contact-making and breaking direction.