Molded Transformer Insulator Block Creepage Design

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Solution Overview

Problem

Molded transformers face challenges in maintaining insulation properties and corrosion resistance when installed in environments with high dust, moisture, and salt content, as existing methods to elongate creepage distance between coils and frames are insufficient.

Innovation Solution

The design incorporates insulator blocks with increased height and the use of wide insulating plates, along with buffer materials and position retaining pins, to extend the creepage distance and enhance corrosion resistance, allowing for improved insulation and ease of maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an insulating member is arranged at the outer circumference of the coil with a length longer than the axial length of the coil, then the insulation property between the coil and outer metal is improved, but the creepage distance between the coil and the frame at upper and lower ends cannot be extended

Engineering Contradiction:
Improveinsulation propertyVSAvoidcreepage distance extension capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The insulator block extends the creepage distance not only in the axial direction (parallel to coil axis) but also in the radial direction (perpendicular to coil axis). This multi-dimensional extension allows the creepage path to traverse through the insulator block's height and width, effectively increasing the total creepage distance between the coil and the frame at upper and lower ends, thereby resolving the limitation of conventional single-direction insulation members

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the creepage distance of insulation is extended to improve insulation property in harsh environments, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveinsulation propertyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulator block integrates multiple functions into a single component: it serves as both the insulation member supporting the coil and the structure extending the creepage distance to the frame. This merged design eliminates the need for separate insulation members and support structures, reducing assembly complexity while maintaining extended creepage distance for improved insulation property in harsh environments

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulator block performs multiple functions simultaneously: providing mechanical support for the coil, extending the creepage distance in both axial and radial directions, and serving as the structural element connecting to the frame. This multi-functionality reduces the overall number of components needed, thereby improving reliability without proportionally increasing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3176796B1Molded transformer
Publication Date: 2020.10.21 HITACHI IND EQUIP SYST CO LTD
  • EP3176796B1 patent drawingFigure 1
  • EP3176796B1 patent drawingFigure 2
  • EP3176796B1 patent drawingFigure 3

AI summary

A molded transformer according to one embodiment of the present invention has a primary coil, and a secondary coil that is disposed inside the primary coil in a state in which a predetermined space is provided between them, wherein the primary and secondary coils are supported by a plurality of support structures. The plurality of support structures are provided between the ends of the primary and secondary coils and a frame, and each of the support structures comprises an insulator block and a wide insulating plate having a wider surface area than the bottom surface area of the insulator block. A top surface of the insulator block is abutted to the ends of the primary and secondary coils, and the wide insulating plate is disposed between the bottom surface of the insulator block and the frame.