Split Core Current Transformer with Integrated Magnetic Actuator
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Solution Overview
Problem
Conventional current transformers for motor protection circuit breakers face issues such as high power loss due to heat generation, lack of integrated electronics for condition monitoring, and increased manufacturing costs due to complex designs and large form factors, limiting efficiency and maintenance opportunities.
Innovation Solution
A cost-effective inline dual coil design with an integrated magnetic actuator, where the current transformer core is split into two portions integrated into upper and lower plates, retained by a secondary coil former, allowing for reduced physical dimensions and lower manufacturing costs, and incorporating embedded electronics for real-time monitoring and communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional current transformers use separate thermal and magnetic protection components, then protection functionality is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines thermal protection (bimetal strip) and magnetic protection (magnetic plunger) components into a single integrated core structure. The core serves as both the magnetic circuit path and the mounting structure for thermal elements, eliminating the need for separate housings and reducing assembly steps while maintaining both protection functions.
Solution Approach 2:
The core structure performs multiple functions simultaneously: it provides the magnetic circuit for the magnetic plunger, serves as the mounting structure for bimetal thermal elements, and acts as the structural framework for the entire protection device. This multi-functionality reduces the number of separate components needed.
2Speed
If conventional current transformers use large form factors, then operational characteristics (speed, prevention from reclosing/welding) are improved, but manufacturing cost increases
Solution Approach 1:
The core is divided into distinct functional segments (magnetic circuit portions and thermal element mounting portions) that can be manufactured separately and then assembled. This segmentation allows for optimized manufacturing of each part while maintaining the overall performance characteristics of the integrated structure.
3Productivity
If conventional current transformers lack integrated electronics, then manufacturing cost is reduced, but operational efficiency and maintenance opportunities are lost
Solution Approach 1:
The patent integrates electronic monitoring components directly into the core structure and surrounding housing. Sensors, communication modules, and processing electronics are incorporated within the same physical envelope as the thermal and magnetic protection elements, enabling real-time monitoring without requiring separate external devices.
4Reliability
If conventional current transformers use complex designs, then protection reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The core is divided into distinct functional segments that can be manufactured using standard manufacturing processes and then assembled together. This segmentation maintains the reliability of the integrated design while enabling easier manufacturing of individual 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 efficient short circuit protection, reduced manufacturing costs, and enhanced operational efficiency by minimizing heat generation and enabling real-time monitoring and communication, while fitting into smaller enclosures.
Implementation Method 1
a magnetic actuator, a current transformer and operational electronics in a dual core circuit breaker
Implementation Method 2
an inline implementation of the primary and the secondary coils to maintain a narrow width
Data Source
Figure 1
Figure 2A~2B
Figure 2C
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 a split core design that is integrated into an upper and lower plate which slide together and are retained by a secondary coil bobbin. Typically, the two parts of the split core can be manufactured into net shapes by utilizing a powder metal or metal injection molding process. Moreover, the split core design disclosed herein can reduce costs and time associated with manufacturing and assembly of the current transformer.