Current Transformer Module Layout for Creepage Distance and Downsizing
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Solution Overview
Problem
Current transformer modules are large in size and require a significant creepage distance for insulation between the primary and secondary coils, posing a challenge in downsizing while maintaining effective insulation.
Innovation Solution
The current transformer module incorporates a U-shaped primary coil and wire-wound secondary coil within a resin-made bobbin, housed in a casing with recesses and protrusions to ensure proper positioning and insulation, and uses a core composed of E-type and I-type core components stacked and bonded to form a single-piece structure, with precise gap adjustment to minimize size and maintain insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the creepage distance for insulation between primary and secondary coils is maintained, then insulation reliability is improved, but the module size increases
Solution Approach 1:
The patent introduces a vertical dimension by stacking the primary and secondary coils on top of each other rather than placing them side by side. The insulation wall extends vertically between the coils, providing the required creepage distance in the vertical direction while minimizing horizontal space occupation, thus reducing overall module size while maintaining insulation reliability
Solution Approach 2:
The patent embeds the primary coil within the bobbin structure and positions the secondary coil above it, with the insulation wall integrated into the bobbin. This nested arrangement allows both coils to occupy overlapping horizontal space at different vertical levels, reducing the overall footprint while maintaining the required insulation distance through the vertical insulation wall
2Volume of moving object
If the bobbin size is reduced for downsizing, then module compactness is improved, but insulation distance maintenance becomes difficult
Solution Approach 1:
The patent applies insulation material selectively in critical areas where electrical breakdown could occur. The insulation wall is concentrated between the primary and secondary coils where the voltage difference is highest, rather than uniformly throughout the entire bobbin. This localized insulation approach maintains adequate insulation distance while minimizing the overall bobbin size
Solution Approach 2:
The patent uses a resin-made bobbin that integrates structural support and insulation functions. The composite resin material provides both mechanical strength to maintain the bobbin's structural integrity at reduced size and electrical insulation properties to maintain the required creepage distance between coils
3Stability of the object's composition
If the primary coil is secured with a contact area, then coil positioning stability is improved, but device complexity increases
Solution Approach 1:
The patent integrates the contact area directly into the casing structure as a recessed portion, merging the positioning function with the housing. The recess in the casing provides both structural support and precise positioning for the primary coil's contact area, eliminating the need for separate positioning components and reducing overall device complexity while maintaining coil stability
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 solution achieves downsizing of the current transformer module while maintaining the necessary creepage distance for insulation, ensuring accurate positioning and stable operation by preventing coil displacement and enhancing manufacturing precision.
Implementation Method 1
A current transformer comprises a primary coil, a secondary coil, and a core for forming a magnetic path common to these coils
Data Source
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AI summary
The present invention provides a current transformer module that can achieve downsizing and keeping the creepage distance of insulation simultaneously. The current transformer module 12 according to the present invention comprises a current transformer 10 and a casing 80 for housing the current transformer, wherein the current transformer includes a resin-made bobbin 20 with a through hollow section 21 and a core 30 having legs 42 inserted at least into the hollow section, the bobbin having a primary coil 26 and a wire-wound secondary coil 27 on the outer periphery of the hollow section, wherein the bobbin has insulation walls 22, 24 between the primary coil and the secondary coil wherein the insulation wall has recesses 23,25, and wherein the casing are provided with protrusions 83, 87 adapted to fit into the recesses.