Thermo-Magnetic Overcurrent Switch With Bistable Contact Opening
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Solution Overview
Problem
Conventional overcurrent protection devices are bulky and less accurate due to the use of bimetallic strips and mechanical springs, requiring more space and additional mechanical parts, and are not bistable, making them less reliable for compact designs.
Innovation Solution
An overcurrent protection device using a thermo-magnetically-shiftable material with conductive and heating properties, which changes magnetically with temperature, allowing for a compact design without mechanical spring return force or gravity, featuring a conductive magnetic module that moves between two stable positions to either permit or break current conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bimetallic strips are used for thermal protection, then protection against moderate overcurrent is achieved, but the device becomes bulky with significant dimensions and small deflection
Solution Approach 1:
The patent combines thermal and magnetic protection functions into a single integrated trigger unit. The bimetallic strip and magnetic coil share a common trigger armature, allowing both protection mechanisms to operate within the same structural framework, thereby reducing overall device volume while maintaining both protection capabilities.
Solution Approach 2:
The trigger armature serves multiple functions: it is actuated by both the bimetallic strip (thermal protection) and the magnetic coil (magnetic protection), and it simultaneously controls the opening of the circuit. This multi-functionality eliminates the need for separate mechanisms, reducing device dimensions.
2Reliability
If conventional bimetallic strips with mechanical springs are used, then thermal protection is achieved, but the device requires additional mechanical parts and more space
Solution Approach 1:
The patent merges the return spring function into the magnetic coil assembly. The magnetic coil not only provides magnetic actuation but also serves as the return mechanism, eliminating the need for a separate mechanical return spring and reducing overall device complexity.
Solution Approach 2:
The magnetic coil performs dual functions: it acts as the actuating mechanism for magnetic protection and simultaneously serves as the return spring for the trigger armature. This multi-functionality reduces the number of mechanical parts required in the device.
3Reliability
If separate thermal and magnetic protection mechanisms are used, then both protection types are achieved, but the device requires more space and additional mechanical parts
Solution Approach 1:
The patent combines thermal and magnetic protection into a single integrated trigger unit where the bimetallic strip and magnetic coil share common components (trigger armature, housing, return mechanism). This integration allows both protection types to function within a compact shared structure, minimizing device area.
Solution Approach 2:
The trigger armature is designed to respond to both thermal (bimetallic strip) and magnetic (coil) stimuli, serving as a universal actuator for both protection mechanisms. This multi-functionality allows both protection types to operate within the same spatial footprint.
4Ease of operation
If conventional non-bistable protection mechanisms are used, then circuit opening is achieved, but the device requires pinion mechanisms to maintain the open state
Solution Approach 1:
The patent removes the pinion mechanism entirely by designing a bistable system where the trigger armature, once actuated, remains in the open position due to the mechanical configuration of the bimetallic strip and magnetic coil interaction. The system maintains state without requiring additional locking mechanisms.
Solution Approach 2:
Instead of using a non-bistable mechanism that requires active locking (pinion), the patent inverts the approach by designing a naturally bistable system where the open and closed states are both stable equilibrium positions, eliminating the need for active locking 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
The solution provides a compact, reliable, and accurate overcurrent protection with reduced parts, achieving fast response times and maintaining the open circuit state without additional mechanical components, effectively integrating thermal and magnetic protections in a single device.
Implementation Method 1
temperature induced by a current that flows through the conductor section
Implementation Method 2
thermo magnetically-shiftable material configured for a magnetically change in dependence on the temperature
Implementation Method 3
conductive magnetic module being movable between only two stable positions, that is a first position faced against said conductive trigger element permitting the conduction of the current and a second position faced against said conductive magnetic core breaking the conduction of the current
Data Source
AI summary
An overcurrent protection device for a circuit to be monitored, having at least one trigger unit, which is configured for an interruption of the circuit in at least one trigger situation and which includes at least one conductor section which is configured for a conduction of a current to be monitored, at least one conductive trigger element, which includes at least one thermo magnetically-shiftable material configured for a magnetic property change in dependence on the temperature induced by a current that flows through the conductor section, a conductive magnetic module, a conductive magnetic core, the conductive magnetic module being movable between a first position faced against the conductive trigger element permitting the conduction of the current through the conductor section and a second position faced against said conductive magnetic core breaking the conduction of the current through the conductor section.