Transformer Iron Core Step-Lap Joints for Low No-Load Noise
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Solution Overview
Problem
Transformers experience high no-load loss and no-load noise due to magnetic field bottlenecks and uneven assembly at the coupling portion of the iron core, which are exacerbated by the use of insulating adhesives applied over the entire laminated surface, leading to curvature and alignment issues.
Innovation Solution
The iron core design features inclined surfaces at the coupling portion of yokes and legs, with a partial application of insulating adhesive around these surfaces, allowing for smooth magnetic field distribution and reduced noise, eliminating the need for penetrating holes and enhancing assembly precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hole penetrating through the iron core is formed to fix the assembled state, then assembly tolerance is improved, but magnetic field bottleneck occurs and no-load loss increases
Solution Approach 1:
The patent removes the harmful penetrating hole from the iron core structure. By eliminating this hole, the magnetic field bottleneck is resolved and no-load loss is reduced, while assembly is fixed through alternative means (clamping structure) that does not compromise magnetic performance
Solution Approach 2:
The patent introduces a clamping structure as an intermediary element to fix the assembled state of the iron core. This mediator provides the necessary mechanical fixation without creating a magnetic field bottleneck, unlike the penetrating hole
2Loss of energy
If insulating adhesive is applied over the entire laminated surface to reduce no-load loss, then magnetic loss is reduced, but no-load noise rapidly deteriorates due to curvature and alignment issues
Solution Approach 1:
The patent applies insulating adhesive only to specific local areas (magnetic flux paths) rather than the entire laminated surface. This selective application maintains low no-load loss while avoiding the curvature and alignment issues that cause no-load noise deterioration
3Strength
If spaced portion is created by stacking sheets at right angles to increase structural rigidity, then rigidity is improved, but magnetic field concentration occurs and iron loss increases
Solution Approach 1:
The patent uses asymmetric stacking of electrical steel sheets at different angles to create both structural rigidity and smooth magnetic flux paths. The asymmetric arrangement prevents magnetic field concentration while maintaining mechanical strength
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 design reduces no-load loss and noise, improving transformer performance by minimizing magnetic field bottlenecks and maintaining even assembly, thus enhancing manufacturing speed and productivity.
Implementation Method 1
a bottleneck phenomenon occurs in which the magnetic field is concentrated in an iron core region in which the spaced portion or the hole is not present
Implementation Method 2
one electrical steel sheet of the yoke is laminated to another electrical steel sheet of the yoke in a step lap method
Implementation Method 3
A transformer is a device changing alternating-voltage and current values using electromagnetic induction
Data Source
AI summary
The present invention relates to an iron core of a transformer having low no-load noise and a manufacturing method therefor, and the iron core of a transformer comprises: a pair of yokes, which are formed by stacking a plurality of electrical steel sheets and the pair of yokes are parallel to each other; and a leg, which is formed by stacking a plurality of electrical steel sheets, and the leg connects the pair of yokes, wherein, in a coupling part in which the yokes and the leg are connected, the ends of the electrical steel sheets of the yokes and the ends of the electrical steel sheets of the leg have inclined surfaces corresponding to each other, the inclined surfaces are shape-fitted, one electrical steel sheet of the yokes is stacked, through step lapping, on another electrical steel sheet of the yokes, and one electrical steel sheet of the leg can be stacked, through step lapping, on another electrical steel sheet of the leg.