Current Transformer with Shading Coil for Equal Secondary Currents
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Solution Overview
Problem
Existing current transformers with multiple secondary windings often distribute output currents unevenly due to different loads, making them unsuitable for many applications.
Innovation Solution
A current transformer design with a primary core, two secondary cores, and a short-circuit winding where both secondary windings have the same number of turns, ensuring equal current delivery at both outputs, regardless of load, by operating them in series.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple secondary windings are used in a current transformer, then the transformer can provide multiple outputs, but the output currents are distributed unevenly depending on the output loads
Solution Approach 1:
The transformer is divided into multiple independent secondary cores (first secondary core, second secondary core) each with its own winding, allowing separate control and optimization of each output channel while maintaining overall system functionality
Solution Approach 2:
A short-circuit winding is introduced as an intermediary element that magnetically couples the primary core with the secondary cores. This short-circuit winding acts as a mediator to ensure equal current distribution across all secondary outputs by providing a common magnetic path and flux distribution mechanism
2Adaptability or versatility
If the number of turns in secondary windings differs, then the transformer can adapt to different load requirements, but the output currents behave according to the turn ratio rather than being equal
Solution Approach 1:
Each secondary winding is designed with identical local characteristics (same number of turns, same wire gauge, same winding geometry) to ensure uniform current distribution. The local quality of each secondary winding is standardized while the overall system maintains adaptability through the magnetic coupling mechanism
3Reliability
If secondary windings are connected in series with the same number of turns, then equal current is provided at both outputs, but the transformer structure becomes more complex
Solution Approach 1:
Multiple secondary cores and their windings are merged into a single integrated transformer structure with common magnetic coupling through the short-circuit winding. This combining approach achieves current equality while avoiding the complexity of separate independent transformers or complex series connection arrangements
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 transformer provides identical currents at both outputs, preventing uneven current division and ensuring reliable performance across varying loads, with the same number of turns in both secondary windings maintaining equal current flow.
Implementation Method 1
A passive component known from the prior art is, for example, the transformer, which enables alternating voltages to be transformed up or down
Implementation Method 2
The core is designed, for example, as a magnetic core made of a soft magnetic material, for example a ferrite
Data Source
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AI summary
The transmitter has a primary core (1) with a primary winding (2), a secondary core (3) with a secondary winding (4) and another secondary core (5) with another secondary winding (6). The primary core, the former secondary core and the latter secondary core are connected with each other by a shading coil (7). The number of windings of the former secondary winding is same as the number of windings of the latter secondary winding.