I-Shaped Lamination Stack for Current Transformer Magnetic Coupling
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Solution Overview
Problem
Conventional current transformer designs suffer from power loss due to heat generation, lack of integrated electronics for condition monitoring, high manufacturing costs, large size, poor magnetic coupling leading to low transformation efficiencies, and excessive magnetic flux shunting, which compromises the trip function and current measurement accuracy.
Innovation Solution
A dual coil current transformer with an integrated magnetic actuator and I-shaped lamination stack, which reduces magnetic flux shunting and improves coupling, enabling smaller enclosures, higher transformation efficiencies, and enhanced current measurement linearity, while providing fast contact opening and efficient overload protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional magnetic core design is used, then the structure is simple, but magnetic coupling is poor leading to low transformation efficiency
Solution Approach 1:
The magnetic core is segmented into multiple laminations stacked together to form the core structure. This segmentation reduces eddy current losses and improves magnetic coupling between the primary and secondary coils, directly addressing the poor magnetic coupling issue while maintaining manufacturing simplicity through standardized lamination components.
Solution Approach 2:
The patent employs composite magnetic core construction using laminated silicon steel sheets or other magnetic materials stacked together. This composite structure enhances magnetic coupling efficiency and reduces flux leakage compared to solid core designs, while the modular nature keeps manufacturing processes manageable.
2Reliability
If conventional current transformer design is used, then the design is simple, but excessive magnetic flux is shunted away compromising trip function
Solution Approach 1:
The patent extracts and removes the magnetic shunt components from the core structure, allowing magnetic flux to follow a more direct path through the core. This eliminates the flux shunting problem that compromises trip function, while the simplified core geometry actually reduces structural complexity compared to designs requiring separate shunt paths.
Solution Approach 2:
The patent introduces a magnetic bridge or yoke structure as an intermediary element that guides magnetic flux efficiently between the core sections. This intermediary component ensures proper flux distribution for reliable trip function without requiring complex external magnetic paths or shunt structures.
3Volume of stationary object
If conventional dual coil design is not used, then the enclosure size can be smaller, but magnetic coupling between coils is insufficient
Solution Approach 1:
The patent employs a nested coil configuration where the secondary coil is positioned within or alongside the primary coil's magnetic field path. This nesting arrangement maximizes magnetic coupling between coils while minimizing the overall enclosure volume, as the coils share space rather than requiring separate compartments.
Solution Approach 2:
The patent optimizes coil winding geometry and spatial arrangement in three-dimensional space, utilizing vertical stacking or layered configurations. This dimensional optimization improves magnetic coupling efficiency without increasing the horizontal footprint, enabling smaller enclosure volume while maintaining transformation efficiency.
4Use of energy by moving object
If conventional circuit breaker design is used, then the operational speed is sufficient, but power loss in the form of heat is significant
Solution Approach 1:
The patent replaces traditional thermal-mechanical trip mechanisms with electromagnetic actuation using the dual coil system. The secondary coil generates electromagnetic force to actuate the trip mechanism, eliminating the need for bimetallic strip heating and reducing power loss while maintaining fast response speed through direct electromagnetic force generation.
Solution Approach 2:
The patent optimizes coil winding parameters, magnetic path length, and air gap dimensions to maximize electromagnetic force generation efficiency. By adjusting these parameters, the system achieves fast contact opening speed with reduced current requirements, thereby reducing power consumption and heat generation compared to conventional designs.
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 results in reduced power consumption, improved transformation efficiencies, higher secondary output current, and enhanced current measurement linearity, enabling smaller, more efficient, and cost-effective circuit breakers with improved operational characteristics.
Implementation Method 1
a primary coil component for providing current based short circuit protection
Implementation Method 2
a secondary coil component for providing voltage based overload protection
Implementation Method 3
magnetic coupling between a core upper and lower plate of the current transformer is improved by employing an I-shaped lamination stack
Data Source
AI summary
A system comprising a magnetic actuator, a current transformer and operational electronics in a dual-coil circuit breaker. The system includes an inline, but non concentric, implementation of the primary and secondary coils to maintain a narrow width suitable for retrofitting in standard industrial rack mounted enclosures. The system further comprises an I-shaped lamination stack that is designed to abut on the ends of an upper and lower plate of the current transformer. The I-shaped lamination stack significantly increases the overlap between the lamination and the upper and lower plates, which results in lower magnetic reluctance and improves magnetic coupling.