Magnetic Overload Safety Device for Rapid Current Interruption
Solution Overview
Problem
Conventional overload safety devices, such as fuses, are slow to interrupt operating currents, leading to potential damage of connected components, especially in rapidly changing current scenarios like those in electric motor vehicles, due to factors like ambient temperature variations and melting properties.
Innovation Solution
An overload safety device with a switching device that uses an actuation element and anchoring element, where the operating current magnetic field induces an opening force to move the interrupter element, independent of the interaction with the operating current magnetic field, ensuring reliable interruption of the current path without dependence on melting properties or ambient temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fuse is used to interrupt operating currents, then the device structure is simple, but the interruption speed is slow and components may be damaged before the fuse acts
Solution Approach 1:
The patent replaces the thermal-mechanical melting mechanism of traditional fuses with a magnetic-mechanical actuation system. A magnetic armature is attracted by a coil-generated magnetic field when overload current flows, mechanically triggering the interrupter element to open the circuit. This magnetic-mechanical conversion enables much faster response compared to thermal melting, directly resolving the contradiction between simple structure and fast interruption speed.
Solution Approach 2:
The patent introduces a magnetic armature as an intermediary element between the electrical overload condition and the mechanical circuit interruption. The armature converts electrical energy (via magnetic field generation) into mechanical motion, which then actuates the interrupter. This intermediary mechanism enables rapid response while maintaining structural simplicity, addressing both the speed and reliability requirements.
2Temperature
If a fuse is designed to conduct admissible current at maximum ambient temperature, then the device can operate at high temperatures, but the load on protected components becomes inadmissibly high at low temperatures due to creeping short circuits
Solution Approach 1:
The patent changes the operating parameter from thermal conduction (temperature-dependent) to magnetic actuation (current-dependent). The magnetic field strength is directly proportional to the overload current magnitude, making the tripping characteristic independent of ambient temperature. This allows the device to reliably detect and respond to overload conditions across the full temperature range from -40°C to 85°C, resolving the contradiction between temperature adaptability and protection reliability.
3Speed
If the switching device is actuated by operating currents above threshold, then the protection response is fast, but the switching device may be affected by the operating current magnetic field interaction
Solution Approach 1:
The patent extracts the magnetic field interaction from the interrupter element itself and applies it separately to the magnetic armature. The interrupter element is designed to be non-magnetic or minimally magnetic, removing the problematic field interaction. Meanwhile, the magnetic armature is specifically designed to respond to the operating current magnetic field, converting it into mechanical actuation. This separation resolves the contradiction by eliminating the adverse effect while preserving the fast response capability.
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 reliable and temperature-independent mechanism to interrupt operating currents, ensuring the safety of connected components by directly utilizing the operating current magnetic field to move the interrupter element, thus preventing component damage from rapid current changes.
Implementation Method 1
a magnetic force is exerted on a magnetic armature by an operating current
Implementation Method 2
a magnetic armature is released from a magnetic retaining device
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an overload safety device (1) for protecting electrical and/or electronic components from operating currents (lb) which are above a threshold operating current. In order to ensure that the overload safety device (1) prevents operating currents (lb) which are above the threshold operating current in a safe, rapid manner which is substantially independent of external factors, there is provision according to the invention for a switching device (6) of the overload safety device (1) to be able to be actuated by operating currents (lb) which are above the threshold operating current and to be constructed so as to be able to be moved from an operating state (B) into a protection state (S) and for the overload safety device (1) to be constructed with a retention device (11) which has at least one retention magnet (12, 13) which secures the operating state (B).