Ground Termination System for Variable Frequency Drive Harness
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Solution Overview
Problem
Variable frequency drive systems face challenges in establishing a low potential ground connection for ground conductors and shields, which is crucial for minimizing impedance and ensuring reliable operation, especially in applications like aircraft where space and weight are critical.
Innovation Solution
A ground termination system that includes a conductive grounding insert and ferrules, which are used to create a low impedance path by engaging with the backshell of an electrical connector assembly, providing a robust and compact ground path within the VFD power cable harness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ground termination methods are used, then the ground connection can be established, but the impedance is high and the physical footprint is large
Solution Approach 1:
The patent combines the ground termination function with the connector backshell by integrating a grounding insert into the backshell structure. The grounding insert includes ground lobe apertures that receive ferrules, which in turn receive ground conductors. This merging of functions eliminates separate ground termination hardware, reducing weight and physical footprint while maintaining reliable ground connections.
Solution Approach 2:
The backshell is designed to serve multiple functions: it provides mechanical support for the connector, houses the grounding insert for ground termination, and structures the lobes for conductor organization. The grounding insert itself serves dual purposes by providing both mechanical support for ferrules and establishing electrical ground paths, thereby reducing the number of separate components needed.
2Reliability
If ground conductors are run separately from power conductors, then grounding path is established, but cable inductance increases and space requirements increase
Solution Approach 1:
The patent merges ground conductors and power conductors into a single twisted pair configuration within the cable harness. This integration reduces the overall volume of the cable harness while maintaining effective grounding. The twisting of ground and power conductors together minimizes inductance and electromagnetic interference, achieving reliable grounding without increased space requirements.
3Loss of energy
If ground conductors are twisted with power conductors, then cable inductance is minimized, but ground potential uniformity becomes difficult to maintain
Solution Approach 1:
The grounding insert is segmented into multiple ground lobe apertures, each receiving a ferrule that terminates a ground conductor. This segmentation allows each ground conductor to be individually terminated and distributed to multiple ground points on the backshell, ensuring uniform ground potential across the entire connector assembly. The segmentation maintains the low inductance benefit of twisted pairs while achieving potential uniformity through distributed grounding.
Solution Approach 2:
The grounding insert is designed to create equipotential zones by providing multiple ground termination points through the ferrules. The conductive material of the grounding insert and backshell ensures that all ground conductors are at the same potential, eliminating ground loops and potential differences. This equipotential design maintains uniform ground potential even when conductors are twisted together.
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 system effectively establishes and maintains a low impedance ground potential uniformly, optimizing installation efficiency and reducing the physical footprint and weight of the hardware, while ensuring reliable operation in various configurations.
Implementation Method 1
The grounding insert and ferrules may be electrically conductive, providing an electrical grounding path for the ground conductors
Data Source
AI summary
A ground termination system may include a backshell for an electrical connector, a grounding insert and a ferrule. The grounding insert includes an outer peripheral edge and a centrally disposed aperture. The outer peripheral edge may be sized to fixedly engage a surrounding portion of the backshell and the centrally disposed aperture may be defined by a plurality of lobes. A first group of the lobes may be sized to receive power conductors of a variable frequency drive power cable. The ferrule may include a crimp barrel and a sleeve. The crimp barrel may receive a ground conductor and be rigidly clamped thereto. The sleeve of the ferrule may fixedly engage one of the lobes in the second group of lobes and anchor the ferrule in the aperture.