Amorphous Core Holding Structure for Transformer Noise Reduction
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Solution Overview
Problem
The existing stationary electromagnetic apparatuses using amorphous cores face noise issues due to magnetostrictive vibrations caused by compressive stress in the laminating direction of amorphous thin strips, which increases with transformer capacity, and there is a trade-off between space factor and noise levels.
Innovation Solution
A core structure for stationary electromagnetic apparatuses is designed with a holding member that has a width equal to or greater than the amorphous metal strips in the laminating direction, preventing compressive stress and reducing noise while maintaining a high space factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the space factor of the amorphous core is increased to reduce transformer size, then the manufacturing compactness is improved, but compressive stress is generated in the laminating direction causing increased noise
Solution Approach 1:
The core is divided into multiple independent amorphous metal strips laminated together, with insulation layers between each strip. This segmentation allows the strips to be stacked to achieve high space factor without generating compressive stress in the laminating direction, thus reducing magnetostrictive vibration noise while maintaining compact transformer size.
2Loss of energy
If amorphous metal strips are laminated without insulation layers to increase space factor, then the power efficiency is improved, but compressive stress increases causing magnetostrictive vibration noise
Solution Approach 1:
Insulation layers are introduced as intermediary elements between adjacent amorphous metal strips. These thin insulation layers prevent electrical contact between strips (reducing eddy current losses and improving power efficiency) while also preventing compressive stress generation in the laminating direction, thereby reducing magnetostrictive vibration noise.
3Manufacturing precision
If compression is applied to increase the space factor of the amorphous core, then the manufacturing precision is improved, but the noise level increases due to magnetostrictive vibrations
Solution Approach 1:
Insulation layers are pre-applied to the surfaces of amorphous metal strips before lamination. This preliminary action ensures that when the strips are stacked and compressed during manufacturing, the insulation layers prevent direct metal-to-metal contact, eliminating compressive stress-induced magnetostrictive vibrations and noise while still allowing precise control of the core's space factor.
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 effectively suppresses compressive stress and noise generated by magnetostrictive vibrations in amorphous cores, allowing for reduced noise levels while maintaining a high space factor and power efficiency.
Implementation Method 1
A magnetic strain is a phenomenon where, when a magnetic flux in a steel plate that forms a core changes, a shape of the steel plate changes in accordance with the change of the magnetic flux. Due to this phenomenon, when the core is subjected to an alternating-current excitation, the core is excited so that the core vibrates and a noise is generated.
Data Source
AI summary
Provided is a core for a stationary electromagnetic apparatus, in which a compressive stress load in the laminating direction of amorphous thin strips that form an amorphous core is suppressed so that noise generated by magnetostrictive vibration is reduced while maintaining a space factor of the amorphous core. The core for a stationary electromagnetic apparatus 10 according to the present invention includes: a laminated body 1 formed of amorphous metal thin strips; and a holding member 2 that holds the laminated body 1, in which a width b of the holding member 2 is equal to or more than a width a of the laminated body 1 in a laminating direction.