Cable-Mounted Circuit Breaker with Pyrotechnic Severing
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Solution Overview
Problem
Existing electrical protection devices for continuous electrical cables suffer from local heating due to electrical connections, leading to oversizing and increased on-board mass, and are prone to unintentional disconnection, which complicates reliability calculations.
Innovation Solution
A connection system that forms a cylindrical tube around the cable, eliminating electrical connections and incorporating a severing system with a blade that moves between inactivated and activated states, using a pyrotechnic charge for activation, and includes a sealing system to isolate the blade from the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If detachable electrical connections are used to enable quick replacement of the protection device, then ease of repair is improved, but local heating by the Joule effect increases and disconnection risk increases
Solution Approach 1:
The patent removes the detachable electrical connections from the system entirely. Instead, the casing is designed to slide directly over the continuous electrical cable, establishing electrical contact through the sliding interface itself. This extraction of the detachable connector eliminates the source of Joule heating while maintaining the ability to replace the protection device by simply sliding the casing off and on the cable.
2Ease of repair
If detachable electrical connections are used to enable quick replacement of the protection device, then ease of repair is improved, but reliability deteriorates due to unintentional disconnection
Solution Approach 1:
The patent eliminates the detachable electrical connections entirely, replacing them with a sliding casing that maintains continuous electrical contact with the cable. The casing slides over the cable and establishes contact through its inner surface, which remains in constant contact with the cable during operation. This design removes the possibility of unintentional disconnection while still allowing intentional replacement by sliding the casing off the cable.
3Ease of repair
If the protection device is designed to be replaceable, then ease of repair is improved, but device complexity increases due to connector design
Solution Approach 1:
The patent removes the complex detachable connector design entirely. The casing is designed as a simple sliding component that fits over the electrical cable without requiring any connectors, terminals, or complex electrical interfaces. The electrical contact is established simply by the casing's inner surface contacting the cable, dramatically simplifying the device structure while maintaining replaceability.
4Reliability
If the blade moves inside a tube during severing operation, then sealing is improved, but the severing system complexity increases
Solution Approach 1:
The patent implements a nested structure where the blade is housed within a tube that forms part of the casing. The blade moves longitudinally inside the tube, which provides a sealed environment for the severing operation. This nesting arrangement allows the blade to be contained and sealed within the tube structure, protecting the severing mechanism while maintaining a relatively compact and integrated design.
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
Eliminates thermal heating and disconnection risks, ensuring reliable and efficient cable severing without additional mass, suitable for high-power electrical circuits in aircraft.
Implementation Method 1
The control means 22 is a pyrotechnic charge which is ignited upon receiving an electrical signal transmitted by an electrical cable 24
Implementation Method 2
the connection system is configured to have an open state in which it allows the electrical cable to be put in place and a closed state in which it surrounds the electrical cable in operation
Implementation Method 3
the severing system 18 comprises a blade 20 which can move between a first position, corresponding to the inactivated state, in which the blade 20 is away from the conductive bar 16, and a second position, corresponding to the activated state, in which the blade 20 has severed the conductive bar 16
Data Source
AI summary
An electrical protection device of circuit-breaker type including a casing, a severing system, positioned in the casing, configured to assume inactivated and activated states corresponding to the on and off states of the electrical protection device, respectively, and a connection system configured to assume an open state in which it allows the electrical cable to be inserted and a second, closed state in which it surrounds the electrical cable. The connection system and the severing system are configured and arranged such that, when the connection system is in the closed state, the severing system severs the electrical cable when passing from the inactivated state to the activated state.