Low-Voltage Circuit Breaker with Mechanical Bypass Switch
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Solution Overview
Problem
Existing low-voltage protective switching devices experience high internal resistance and power loss due to disconnection contacts, limiting nominal currents and increasing construction size, which results in reduced semiconductor lifespan and reliability.
Innovation Solution
A low-voltage protective switching device design featuring a mechanical bypass switch, a semiconductor circuit arrangement connected in parallel, a current measuring arrangement, and an electronic control unit that controls the bypass switch and semiconductor circuit upon detecting overcurrent, with a first mechanical disconnecting switch in series to the semiconductor circuit and parallel to the bypass switch, reducing internal resistance and intrinsic heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If disconnection contacts are used to provide galvanic separation, then safety and reliability are improved, but internal resistance increases and power loss increases
Solution Approach 1:
The patent applies dynamics by making the disconnection contacts movable rather than fixed, allowing them to be in different positions (connected or disconnected) based on operational requirements. The actuator mechanism enables dynamic switching between safety mode (disconnected) and low-resistance mode (connected), resolving the contradiction between reliability and power loss.
Solution Approach 2:
The disconnection contacts are periodically connected and disconnected based on operational phases. During normal operation, they remain connected to minimize resistance. During fault conditions or maintenance, they are disconnected to provide safety isolation. This periodic action allows the system to alternate between the two conflicting requirements.
2Reliability
If disconnection contacts and cabling are used for galvanic separation, then safety is improved, but construction size increases
Solution Approach 1:
The patent merges the disconnection contact function with the existing circuit breaker structure. The disconnection contacts are integrated into the same housing and mechanism as the main switching contacts, eliminating the need for separate isolation switches and reducing overall construction size while maintaining safety functionality.
Solution Approach 2:
The actuator mechanism serves multiple functions: it operates both the main switching contacts and the disconnection contacts. This multi-functionality reduces the number of separate components needed, thereby reducing construction size while maintaining the required safety isolation capability.
3Reliability
If high-quality design of contacts is used to handle continuous current, then reliability is improved, but electrical resistance cannot be avoided
Solution Approach 1:
The contact system is designed to be dynamic, allowing the disconnection contacts to switch between connected and disconnected states. When connected, high-quality contacts minimize resistance for reliable current handling. When disconnected, they provide complete isolation. This dynamic capability resolves the contradiction between maintaining low resistance and ensuring reliability.
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 design achieves low internal resistance, reducing intrinsic heating and maintaining low interior temperatures, thereby increasing semiconductor lifespan and reliability while enabling high continuous currents and compact construction.
Implementation Method 1
a current measuring arrangement disposed in the outer conductor path, the current measuring arrangement being connected with the electronic control unit
Implementation Method 2
a first semiconductor circuit arrangement of the low-voltage protective switching device connected parallel to the mechanical bypass switch
Implementation Method 3
When the protective switching device is switched off, first the bypass switch is opened, wherein an electrical arc results, and the current commutates onto the semiconductor circuit arrangement
Implementation Method 4
an electronic control unit; a current measuring arrangement disposed in the outer conductor path, the current measuring arrangement being connected with the electronic control unit
Data Source
AI summary
A low-voltage protective switching device includes: at least one outer conductor path from an outer conductor supply terminal of the low-voltage protective switching device to an outer conductor load terminal of the low-voltage protective switching device; a neutral conductor path from a neutral conductor terminal of the low-voltage protective switching device to a neutral conductor load terminal of the low-voltage protective switching device; a mechanical bypass switch disposed in the outer conductor path; a first semiconductor circuit arrangement of the low-voltage protective switching device connected parallel to the mechanical bypass switch; an electronic control unit; a current measuring arrangement disposed in the outer conductor path, the current measuring arrangement being connected with the electronic control unit; and a first mechanical disconnecting switch disposed in series to the first semiconductor circuit arrangement and in parallel to the mechanical bypass switch. The electronic control controls the mechanical bypass switch.