Magnetic Core Holding Flaps for Current Sensor Contact
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Solution Overview
Problem
Magnetic cores in current sensors experience energy losses and signal disturbances due to eddy currents and parasitic capacitances, which impair measurement accuracy, and existing grounding methods require maintaining a minimum contact normal force over the core's lifetime.
Innovation Solution
A magnetic core design with contact insertion holes featuring stacked holding flaps that act like leaf springs to ensure a consistent contact normal force, potentially covered with insulating material and arranged to allow for easy adjustment and self-centering of the plug contact, reducing eddy currents and maintaining contact integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a pin is inserted into the magnetic core to shortcut eddy currents and connect to ground potential, then energy losses are reduced and measurement accuracy is improved, but the contact normal force may decrease over the lifetime of the magnetic core
Solution Approach 1:
The contact insertion hole is divided into multiple holding flaps (at least two) that are stacked with respect to the insertion direction. Each flap independently contacts the plug contact, distributing the contact force and ensuring that the overall contact normal force is maintained even if individual flaps wear or deform over time.
Solution Approach 2:
The holding flaps are designed to be elastically deformable, allowing them to bend during plug contact insertion and then spring back to exert a continuous contact normal force. This dynamic behavior ensures consistent electrical contact over the lifetime of the magnetic core, compensating for wear and deformation.
2Force
If holding flaps are made longer to increase contact normal force, then the force by which the plug contact is retained is improved, but the manufacturing precision and positioning difficulty increase
Solution Approach 1:
Instead of increasing the length of single holding flaps in one dimension, the solution stacks multiple holding flaps in the insertion direction (adding a dimension to the structure). This provides sufficient contact normal force through cumulative effect while keeping each individual flap short enough to maintain manufacturing precision and easy positioning.
3Reliability
If multiple layers of magnetic sheet material are used to form holding flaps, then the contact normal force and structural integrity are improved, but the device complexity increases
Solution Approach 1:
The holding flaps serve multiple functions: they provide mechanical retention of the plug contact, ensure electrical contact by shortcutting eddy currents, and offer elastic compliance for consistent force application. The same stacked layer structure achieves all these functions simultaneously, reducing the need for additional separate 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 design effectively reduces energy losses and signal disturbances by ensuring a consistent contact normal force, improving measurement accuracy and longevity by minimizing corrosion and deformation, while allowing for easy adjustment and self-centering of the plug contact.
Implementation Method 1
Each holding flap acts like a lamella which is bent by the insertion of the plug contact. The bent flap works like a leaf spring and thus ensures the required contact normal force.
Implementation Method 2
Magnetic core for conducting a magnetic field, generated by currents (I) flowing through a central opening (6) of the magnetic core (1)
Implementation Method 3
each layer (18) may be covered by an electric insulating material such as an insulating varnish
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a magnetic core (1) for conducting a magnetic field, in particular to a magnetic core (1) as it is used for current sensing. The magnetic core (1) has at least one contact insertion hole (12) for mounting a plug contact (14). The contact insertion hole (12) penetrates the magnetic core (1) at least partially and extends in an insertion direction (16). If the plug contact (14) is inserted into the contact insertion hole (12) and the plug contact (14) is connected to a ground potential, switching disturbances can be suppressed. In order to ensure a constant minimum contact normal force acting between the magnetic core (1) and the inserted plug contact (14), at least two holding flaps (24, 26) are provided according to the invention, that are stacked with respect to the insertion direction (16) and extends substantially perpendicular to the insertion direction (16).