Stationary Induction Apparatus Step Lap Joint Flux Distribution
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Solution Overview
Problem
Existing stationary induction electric apparatuses, such as transformers, face challenges in achieving smooth magnetic flux distributions due to high magnetic flux densities at the inner periphery and low densities at the outer periphery of the iron core, leading to increased eddy current losses and difficulties in processing thin amorphous materials, which limits the adjustment of overlap margins and results in insufficient magnetic flux smoothing and increased transformer size and cost.
Innovation Solution
A stationary induction electric apparatus with a laminated wound iron core featuring a step lap joint portion on the inner peripheral side and an overlap joint portion on the outer peripheral side, where the gap distances between the ends of the step lap joint are gradually shortened and the overlap distances are increased towards the outer peripheral side, respectively, to improve magnetic flux distribution smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If overlap margins are shortened to adjust magnetic resistance, then magnetic flux distribution smoothness is improved, but fixation difficulty increases and iron loss deteriorates
Solution Approach 1:
The joint structure is divided into multiple segments with different overlap margin lengths. The inner peripheral side has longer overlap margins for stable fixation, while the outer peripheral side has shorter overlap margins for magnetic flux smoothing. This segmentation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
Different regions of the joint structure are given different overlap margin characteristics. The inner peripheral side uses longer overlap margins to ensure mechanical stability and reduce iron loss, while the outer peripheral side uses shorter overlap margins to improve magnetic flux distribution smoothness. This local differentiation resolves the contradiction by allowing each area to have the quality it needs.
2Manufacturing precision
If overlap margins are increased to smooth magnetic flux distribution, then magnetic flux smoothness is improved, but transformer size and cost increase
Solution Approach 1:
Instead of uniformly increasing overlap margins throughout the entire joint structure, the invention applies different overlap margin lengths to different regions. The outer peripheral side, where magnetic flux smoothing is most needed, receives the benefit of optimized overlap margins, while the inner peripheral side maintains adequate but not excessive overlap margins for fixation, thus avoiding unnecessary volume increase.
Solution Approach 2:
The joint structure is segmented into regions with different overlap margin requirements. This allows the transformer design to achieve magnetic flux smoothing only where necessary (outer peripheral side) rather than throughout the entire structure, thereby minimizing the overall volume and cost increase while still achieving the desired magnetic flux distribution improvement.
3Reliability
If amorphous materials are used to improve magnetic characteristics, then magnetic properties are improved, but processing difficulty increases due to thinness and hardness
Solution Approach 1:
The amorphous material sheets are processed and assembled in a segmented manner, with the joint structure divided into multiple portions that are separately prepared and then combined. This segmentation makes the handling and assembly of thin, hard amorphous materials more manageable while preserving their excellent magnetic properties in the final wound iron core.
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 enhances the smoothness of magnetic flux distributions within the iron core while maintaining a simple apparatus design, reducing iron losses, and minimizing the increase in transformer size and cost by effectively controlling magnetic resistances and exciting currents.
Implementation Method 1
magnetic flux densities tend to be high in the inner periphery of the iron core, and magnetic flux densities tend to be lower in the portions closer to the outer periphery
Implementation Method 2
gap distances between the ends of the step lap joint potion are gradually shortened toward the outer peripheral side
Implementation Method 3
eddy current losses increase due to magnetic flux concentrations generated by magnetic flux crossings at the ends of the wound iron core
Data Source
AI summary
There is provided a static induction electric apparatus capable of improving smoothnesses of magnetic flux distributions inside iron cores. A stationary induction electric apparatus including wound iron cores and a winding, wherein each of the wound iron cores is a laminated body of magnetic materials that are lap-joined and at least provided with a step lap joint portion on an inner peripheral side of the wound iron core, and gap distances between ends of the step lap joint potion are gradually shortened toward an outer peripheral side of the wound iron core. Although a configuration of the stationary induction electric apparatus is simple, the stationary induction electric apparatus having improved smoothnesses of magnetic flux distributions inside the iron cores can be provided.