Braided Flat Winding Wire for High Space-Factor Motor Coils

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Solution Overview

Problem

Conventional electric wires and coils for rotating machines face challenges in increasing space factor while facilitating winding, suppressing eddy currents, and achieving small size, high output, and high efficiency.

Innovation Solution

A braided enamel wire is used to form a flat or square wire with connection bundles that can be connected in series or parallel, allowing for easy winding and reducing eddy currents, thereby increasing the space factor and improving heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a thick electric wire for winding is used to increase output, then the output can be easily increased, but the space factor is decreased

Engineering Contradiction:
ImproveoutputVSAvoidspace factor
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The electric wire is segmented into multiple thin wires bundled together (multi-core structure), allowing the coil to achieve high output through increased ampere-turns while maintaining a compact space factor. Each thin wire carries a portion of the total current, and their combined effect achieves the desired output without requiring a single thick wire that would occupy excessive space.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining multiple thin insulated wires into a bundled configuration. This composite wire structure optimizes both electrical performance (high current carrying capacity) and spatial efficiency (reduced cross-sectional area), resolving the contradiction between output and space factor.

Inventive Principle:
Principle #40Composite materials

2Area of stationary object

If a square wire or flat wire manufactured by rolling a round wire is used to improve space factor, then the space factor is improved, but the wire becomes difficult to wind due to twisting and corner interference

Engineering Contradiction:
Improvespace factorVSAvoidwinding processability
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The wire is divided into multiple flexible thin cores bundled together, each capable of independent bending. This segmentation eliminates the twisting and corner interference problems associated with solid square or flat wires, as the flexible bundled structure can easily navigate winding paths and tight corners while maintaining the space factor benefits of non-round geometry.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the structural parameters of the wire from a solid non-round cross-section to a bundled multi-core configuration. This parameter change maintains the space factor advantage of non-round wires while fundamentally improving winding processability by introducing flexibility and eliminating the rigidity-induced twisting and corner interference problems.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a litz wire made by twisting thin round wires is used to facilitate winding, then the wire becomes flexible and easy to wind, but the space factor is not improved compared to round wire

Engineering Contradiction:
Improvewinding flexibilityVSAvoidspace factor
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The invention creates a composite wire structure where multiple thin wires are bundled and insulated, combining the flexibility advantage of litz wire with the space factor benefit of non-round geometry. The bundled configuration allows the wire to bend easily like litz wire while the overall non-round cross-section optimizes space utilization in the coil winding, achieving both flexibility and improved space factor simultaneously.

Inventive Principle:
Principle #40Composite materials

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 enables easy winding around small cores, suppresses eddy currents, and enhances efficiency by increasing the space factor and reducing resistance, allowing for more current flow and downsizing the coil.

Implementation Method 1

suppresses eddy currents

Methodology Applied
Scientific EffectEddy current suppression: Eddy Currents

Implementation Method 2

coil for rotating machine comprising a wound electric wire for winding

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3550575B1Coil for rotating machine using electric wire for winding
Publication Date: 2026.03.25 O T I CO LTD
  • EP3550575B1 patent drawingFigure 1
  • EP3550575B1 patent drawingFigure 2(A)~2(C)
  • EP3550575B1 patent drawingFigure 3(A)~3(F)

AI summary

A winding electric wire according to one embodiment of the present invention enables a space factor to be increased and an eddy current to be suppressed, despite using an easy winding process. A winding electric wire 1 is configured such that one enameled wire (la) or a plurality of enameled wires (la) bundled in parallel or in a litz form are braided so as to be formed into a belt-like rectangular or square wire shape comprising flat braided wires forming flatly-molded layers the number of which is two or a multiple of two. By spirally winding the electric wire, a coil that is easily wound regardless of the presence of a core, that has a high space factor, and that causes less eddy currents is obtained.