Dielectric Composite Cradle for AC Air Core Reactors

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Solution Overview

Problem

Air core reactors, particularly AC types, face challenges with ferrous cradle materials heating up due to strong magnetic fields, leading to energy wastage and structural instability, while existing solutions for DC reactors are not effectively adaptable for AC systems.

Innovation Solution

A cradle configured in a star or wheel form, at least partially made from dielectric materials, such as fiberglass composite or porcelain, to eliminate eddy current paths and mitigate electromagnetic heating, using non-ferrous materials for structural support and thermal management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ferrous material is used for the cradle to provide structural support, then the cradle can support the heavy coil, but the magnetic field causes the ferrous material to heat up due to eddy currents

Engineering Contradiction:
Improvestructural support capabilityVSAvoidenergy wastage due to eddy currents
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent applies composite materials by combining non-ferrous structural members (for mechanical strength) with dielectric material members (for electrical insulation and eddy current elimination). This composite structure provides both the required structural support and the electrical properties to prevent eddy current heating in the magnetic field environment.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by using different materials for different parts of the cradle structure. Non-ferrous materials are used in regions requiring structural support, while dielectric materials are used in regions where electrical insulation and eddy current prevention are critical. This localized material selection optimizes both mechanical and electrical performance.

Inventive Principle:
Principle #3Local quality

2Strength

If ferrous material is used for the cradle, then structural strength is provided, but electromagnetic heating occurs making the solution unacceptable for AC reactors

Engineering Contradiction:
Improvestructural strengthVSAvoidcradle temperature due to induction heating
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent uses composite materials combining non-ferrous structural members with dielectric material members. The non-ferrous materials provide structural strength while the dielectric materials prevent electromagnetic heating by blocking eddy current paths, thus solving both the strength and temperature issues simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The dielectric material members act as intermediaries between the magnetic field and the structural members. These intermediate elements prevent direct interaction between the magnetic field and ferrous materials, thereby eliminating induction heating while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If DC reactor solutions are applied to AC reactors, then mounting capability is provided, but eddy current paths are created causing heating

Engineering Contradiction:
Improveadaptability of mounting solutionVSAvoidenergy loss from eddy currents
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent adapts the DC reactor mounting solution for AC reactors by using composite materials. The cradle combines non-ferrous structural members with dielectric material members, creating a structure that can be mounted on insulators like DC reactors while preventing eddy current paths that would cause heating in AC magnetic fields.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters of the cradle from purely ferrous to a composite of non-ferrous and dielectric materials. This parameter change in material composition eliminates eddy current paths while maintaining the mounting capability required for AC reactor applications.

Inventive Principle:
Principle #35Parameter changes

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 dielectric cradle design effectively reduces energy wastage and structural instability by minimizing eddy currents and induction heating, ensuring efficient load transmission and long-term durability in AC air core reactors.

Implementation Method 1

The plurality of outer members are formed from a dielectric material... to eliminate eddy current paths and/or mitigate electromagnetic heating

Methodology Applied
Scientific EffectEddy Currents: Eddy Currents

Implementation Method 2

This magnetic field causes the ferrous material of the cradle to heat up. The energy used in heating the cradle is wasted

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP3357076B1Composite cradle for use with coil of air core reactors
Publication Date: 2022.08.03 HSP HOCHSPANNUNGSGERATE GMBH
  • EP3357076B1 patent drawingFigure 1A~1B
  • EP3357076B1 patent drawingFigure 2~3
  • EP3357076B1 patent drawingFigure 4

AI summary

A cradle (200) to mount a coil (405) of an electric power line reactor (400) is provided. The cradle (200) includes a plurality of a pair of opposing arms (215(1-4)). Each arm 215 has a free end (225(1-4)) and an end coupled to a hub (220). The free end (225) of each arm (215) is configured to be coupled to a bearing assembly. The cradle (200) further includes a plurality of outer members (235(1-4)). The free ends of each pair of adjacent arms (215(1-2)) of the plurality of a pair of opposing arms (215(1-4)) are coupled to a corresponding outer member (235) of the plurality of outer members (235(1- 4)). At least one outer member (235) of the plurality of outer members (235(1-4)) is formed from a dielectric material and the plurality of a pair of opposing arms (215(1-4)) being formed from a material that enables the cradle (200) to support weight of the coil (405).