Relay Double Interruption Arc Energy Reduction
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Solution Overview
Problem
In DC applications, particularly in vehicles with 24VDC or 48VDC, existing relays face challenges in quickly and safely extinguishing the arc that occurs between relay contacts and the approaching contact spring during closure, leading to high arc energy.
Innovation Solution
A relay design featuring synchronous double interruption using two series-connected contact springs with a stationary intermediate contact part and a magnetic drive that generates repelling magnetic fields to increase contact force, reducing arc energy and preventing dynamic lifting due to constriction forces or short-circuit currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single contact spring is used to close the circuit between relay contacts, then the device complexity is reduced, but the arc energy generated during contact closure increases
Solution Approach 1:
The single contact spring is divided into two series-connected contact springs (51, 52) that operate independently. Each spring creates its own arc that is shorter and lower energy compared to a single long arc spanning the entire contact distance. The segmentation of the circuit interruption path directly reduces the harmful arc energy generated during switching operations.
2Speed
If contact springs are made lightweight for fast response, then the switching speed is improved, but the contact force decreases making the contacts more susceptible to dynamic lifting from constriction forces or short-circuit currents
Solution Approach 1:
Two contact springs are combined in series configuration, where both springs work together to provide enhanced contact force at the relay contacts. The magnetic fields generated by current flowing through both springs create a synergistic repelling effect that presses the contact buttons firmly against the relay contacts, preventing dynamic lifting while maintaining fast response characteristics.
Solution Approach 2:
The mechanical spring force is supplemented and enhanced by electromagnetic forces. The magnetic fields generated by current flowing through the contact springs create repelling magnetic forces that add to the mechanical spring pressure, ensuring reliable contact engagement without requiring heavier mechanical springs that would slow down the switching response.
3Reliability
If a stationary intermediate contact part is introduced to support two contact springs, then the reliability of contact engagement is improved, but the device complexity increases
Solution Approach 1:
The stationary intermediate contact part serves multiple functions simultaneously: it provides mechanical support for both contact springs, acts as an electrical connection point in the series circuit, and serves as a structural anchor for the magnetic drive mechanism. This multi-functionality justifies the additional component by eliminating the need for separate support structures.
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
The solution effectively halves arc energy and enhances contact reliability by synchronously deflecting contact springs, making it more difficult for dynamic lifting and increasing contact force between relay contacts, thereby reducing bounce and arc occurrence.
Implementation Method 1
mutually repelling magnetic fields, which are generated by the current flowing through the contact springs in opposite directions
Implementation Method 2
magnetic coil with reversible polarity and an armature rocker which has a permanent magnet and which can be pivoted between two end positions on the magnetic coil
Data Source
Figure 1~2
AI summary
The relay (1) has an electric circuit that is arranged between two relay contacts (2,3), for closing or interrupting a contact spring device (4). A stationary intermediate contact portion (6) is arranged between two contact springs (5-1,5-2) of the spring device. A magnetic drive (11) for synchronous deflection of the springs, is provided in a closed or opened relay position of the relay contacts. The springs are coupled pivotably in a quiescent state through a pair of link arms (17a,17b) displaced in moving direction of respective springs.