Aircraft Cable Neutral Conductor Segmentation for Torsion Resistance
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Solution Overview
Problem
Existing electrical cables for aircraft with high-frequency applications face mechanical stress issues due to torsion during winding and unwinding, leading to potential damage of the central neutral or return conductor, and increased skin effect from harmonics, which can result in inoperability and excessive inductive voltage drops.
Innovation Solution
The cable features multiple individually insulated neutral conductors with a combined cross-section equivalent to a single solid conductor, surrounded by a resilient non-electrical central element, providing redundancy and maintaining low inductance, thus enhancing mechanical and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single solid central neutral conductor is used, then the cable structure is simple and manufacturing is easy, but the conductor is susceptible to mechanical damage from torsion and bending stress
Solution Approach 1:
The single solid central neutral conductor is divided into multiple individual conductors (typically three conductors arranged in a triangle). Each conductor is insulated separately and they are distributed around the cable center, converting a single vulnerable element into multiple redundant elements that can better withstand mechanical stress.
2Reliability
If the neutral conductor cross-section is increased to handle harmonics, then the electrical capacity improves, but the cable diameter increases and mechanical flexibility deteriorates
Solution Approach 1:
The neutral conductor cross-section is segmented into multiple smaller conductors arranged in a triangular configuration around the cable center. This distribution allows the total cross-sectional area to remain sufficient for handling harmonic currents while maintaining a compact overall cable diameter that preserves mechanical flexibility.
Solution Approach 2:
Instead of increasing the cross-sectional area in a single dimension (which would increase cable diameter), the conductors are arranged in a two-dimensional triangular pattern around the center, distributing the electrical capacity across different spatial positions while maintaining compact overall dimensions.
3Strength
If mechanically reinforced core is added to the central neutral conductor, then torsion resistance improves, but the cable center becomes thicker and phase insulation must be thicker
Solution Approach 1:
The mechanical reinforcement is achieved by segmenting the neutral conductor into multiple elements arranged in a triangle, rather than adding a separate reinforcement layer. The triangular arrangement of three conductors inherently provides torsional resistance while maintaining a compact center structure that does not require additional thickening of phase insulation.
4Stability of the object's composition
If the cable is designed for permanent installation, then the structure can be optimized for stability, but the cable lacks flexibility for repeated winding and unwinding operations
Solution Approach 1:
The segmentation of the neutral conductor into multiple flexible individual conductors arranged in a triangle provides both structural stability through their geometric configuration and flexibility for repeated winding and unwinding operations. Each individual conductor can bend independently while maintaining the overall triangular structure.
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 design improves flexibility and torsion resistance while reducing the risk of central conductor breakage and skin effect, ensuring reliable electrical performance without increasing the cable diameter, and minimizing inductive voltage drops even at high frequencies.
Implementation Method 1
the skin effect and thus the load in this is disadvantageously increased
Implementation Method 2
every increase in inductance causes an 8 times higher inductive voltage drop than would be the case with 50 Hz currents
Data Source
Figure 1
AI summary
The invention relates to an electrical cable for supplying aircraft and similar devices with alternating current having at least partially higher frequencies of preferably 400 Hz. The cable is provided with a central neutral and/or return conductor (1) and at least six phase conductors (2a, 2b, 3a, 3b, 4a, 4b) arranged in a concentrically distributed manner about same, wherein every phase is distributed on two symmetrically opposing phase conductors (2a, 2b, 3a, 3b or 4a, 4b). The neutral and/or return conductor (1) is formed, in a very space-saving manner and with low inductivity, by preferably six individually insulated compact neutral wires (16), the total cross-section of which approximately corresponds to the cross-section of an individual solid neutral wire. In this way, with six-fold redundancy, the risk of a neutral wire failure is reduced, without diminishing the electrical properties with the inductive voltage drop.