Current Transformer Staggered Windings for Small Current Performance
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Solution Overview
Problem
Existing current transformers in universal circuit breakers face limitations in output energy due to restricted volume, which prevents them from automatically cutting off circuits during small transient short circuit currents without external power, especially when the current is a multiple of the minimum rated current.
Innovation Solution
The design incorporates a closed magnetic circuit with multiple branch magnetic circuits that form secondary windings, arranged in a staggered manner to increase the number of turns and energy output within the same volume, utilizing idle space without increasing the overall size of the transformer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the volume of the current transformer is increased to provide more secondary windings, then the output energy increases, but the device size increases
Solution Approach 1:
Multiple secondary windings are nested within the same magnetic core structure, with each winding placed in a different spatial layer or position around the primary conductor. This allows multiple windings to occupy the same volume space without increasing the overall transformer dimensions, thereby increasing output energy while maintaining compact size.
Solution Approach 2:
The patent arranges secondary windings in three-dimensional space around the primary conductor, utilizing radial and axial dimensions. Instead of stacking windings linearly in one direction, the windings are distributed in multiple spatial dimensions (different radii and angles), effectively packing more windings into the same volume without increasing the transformer's external dimensions.
2Power
If multiple secondary windings are added to increase output energy, then the energy output improves, but the device complexity increases
Solution Approach 1:
Multiple secondary windings share a common magnetic core and are positioned around a single primary conductor, merging the magnetic circuit structure. This unified approach allows multiple windings to benefit from the same magnetic flux path without requiring separate magnetic circuits, reducing overall structural complexity while maintaining high output energy.
Solution Approach 2:
The magnetic core structure serves multiple functions simultaneously: it provides the magnetic path for all secondary windings, supports the insulation framework, and maintains the geometric arrangement of multiple windings. This multi-functionality reduces the need for additional supporting structures, thereby increasing output energy without proportionally increasing device complexity.
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
This configuration significantly enhances the output energy of the current transformer, improving the performance of circuit breakers under small current conditions without increasing the volume or size, enabling automatic circuit cutoff even at low transient currents.
Implementation Method 1
a current transformer comprises a closed magnetic circuit, a first part of the closed magnetic circuit completely surrounds a primary conductor, and a second part of the closed magnetic circuit forms a secondary winding
Data Source
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AI summary
The present invention discloses a current transformer which comprises a closed magnetic circuit and a secondary winding. A first part of the closed magnetic circuit completely surrounds a primary conductor, and a second part of the closed magnetic circuit forms the secondary winding, the second part of the closed magnetic circuit serves as a magnetic core of the secondary winding. The closed magnetic circuit forms a plurality of branch magnetic circuits at the second part, and a secondary winding is formed on each branch magnetic circuit, each branch magnetic circuit serves as a magnetic core of a corresponding secondary winding, each secondary winding is staggered with each other in at least one of the length, the height and the thickness. The current transformer of the present invention fully utilizes the idle space therein. A plurality of secondary windings are arranged in a spatial interleaving manner and a plurality of secondary windings are arranged in a spatial interleaving manner, the plurality of secondary windings significantly increase a total energy outputted by the circuit transformer. Larger output energy is obtained under a same volume, and a performance of the circuit breaker under a small current condition can be improved.