Contactor Bypass Circuit Using Solid-State Arc Prevention

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Solution Overview

Problem

In aerospace electric power generation and distribution systems, short circuit events can lead to the formation of high energy arcs across main contacts, preventing isolation and requiring the use of one-time use fuses that need to be replaced.

Innovation Solution

A high voltage contact control system that includes a short circuit protection system with solid state arc prevention elements, which can operate in multiple modes to divert current away from main mechanical contacts, reducing or eliminating arcing and allowing for reusable protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional fuses or pyrofuses are used to protect against arcs during short circuit events, then arc protection is provided, but the protection device becomes one-time use and requires replacement

Engineering Contradiction:

Improvearc protectionVSAvoiddevice replacement

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces mechanical fuses with solid state arc prevention elements (transistors) that can be electronically controlled to provide arc protection during contact opening, eliminating the need for one-time use mechanical fuse devices

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters of the solid state arc prevention elements by controlling their resistance states (high resistance to block arcs, low resistance to allow normal current flow), enabling reusable arc protection instead of single-use fuses

Inventive Principle:

Principle #35Parameter changes

2Ease of repair

If solid state arc prevention elements are used to provide reusable protection, then device reusability is achieved, but system complexity increases

Engineering Contradiction:

Improvedevice reusabilityVSAvoidprotection system structure

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The patent divides the arc prevention function into multiple solid state elements (first and second arc prevention elements) that can be independently controlled, allowing sophisticated arc protection while maintaining modularity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of solid state arc prevention elements through a controller that adjusts their resistance states in real-time based on contact opening status, enabling adaptive arc protection without permanent complex hardware

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If current is diverted away from main contacts during short circuit, then arcing is reduced or eliminated, but control system complexity increases

Engineering Contradiction:

ImprovearcingVSAvoidcontrol system

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by controlling the solid state arc prevention elements to establish alternative current paths before the mechanical contacts open, preventing arc formation in advance rather than reacting after arcs occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces solid state arc prevention elements as intermediary components that mediate current flow between power sources and loads, providing controlled alternative paths that prevent direct arcing across mechanical contacts

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces or eliminates arcing during short circuit events, allowing for safe and reliable contact opening without the need for replaceable fuses, and enables non-destructive testing of the protection system.

Implementation Method 1

a first solid state arc prevention element that can operate in at least two modes; a second solid state arc prevention element connected in series with the first solid state arc prevention element

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4550378A1Contactor short circuit protection system with arc-preventing bypass parallel path comprising solid state devices

Publication Date: 2025.05.07 HAMILTON SUNDSTRAND CORP

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Figure 3A

AI summary

A high voltage contact control system includes main contacts on positive and negative feeder lines and a short circuit protection system configured between the positive feeder line and the negative feeder line. The short circuit protection system is configured to be operably connected between the positive and negative feeder lines and configured to selectively provide a bypass path between the positive feeder line and the negative feeder line to divert current away from the first and second contacts. The short circuit protection system includes first and second state arc prevention elements (304a, 304b) that can operate in at least two modes. The bypass path is established by having one of the arc prevention elements in a fully on mode and another either fully on or in a linear mode.