Mechanical Switch Handle Positions for Solid-State Circuit Breakers

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Solution Overview

Problem

Designing a mechanical switch for solid-state circuit breakers that meets the requirements of short breaking time, no arc upon breaking, long electrical life, and no noise is a challenging task in the industry.

Innovation Solution

A solid-state circuit breaker is proposed, featuring an electronic switch and a mechanical switch connected in series. The mechanical switch includes a housing, a handle with defined positions, movable and stationary contacts, and a transmission assembly to achieve contact and separation. The handle stops at clear positions indicating the switch's state, ensuring correct indication and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical switch is designed for solid-state circuit breaker, then the breaking time is shortened and electrical life is extended, but the indication of switch state becomes unclear and ambiguous

Engineering Contradiction:
Improveelectrical lifeVSAvoidswitch state indication
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The handle's motion path is segmented into three distinct positions (on position, off position, and charged position), with the off position further divided into two separate stopping points. This segmentation allows the system to clearly indicate different operational states including tripped and released conditions, resolving the ambiguity in switch state indication while maintaining the reliability benefits of mechanical switching.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a mechanical switch is designed for solid-state circuit breaker, then the breaking time is shortened and electrical life is extended, but the complexity of the switch structure increases

Engineering Contradiction:
Improveelectrical lifeVSAvoidmechanical switch structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The transmission assembly is designed to perform multiple functions: it connects the handle to the movable contact, provides resetting functionality through the resetting member, and enables clear state indication through the dual off-position design. By integrating these functions into a single assembly, the overall structural complexity is managed while achieving the desired reliability and indication capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of information

If the handle stops at multiple positions, then the switch state indication becomes clear and correct, but the ease of operation is reduced

Engineering Contradiction:
Improveswitch state indicationVSAvoidhandle operation
Core Design Contradiction:
Loss of informationVSEase of operation

Solution Approach 1:

The resetting member is designed to automatically return the handle to the charged position (a specific off position) when the circuit breaker trips, without requiring manual intervention. This self-resetting mechanism simplifies operation by eliminating the need for users to manually reset the handle after tripping, while still providing clear state indication through the distinct positioning of the handle.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4498399A1Solid-state circuit breaker
Publication Date: 2025.01.29 SCHNEIDER ELECTRIC (CHINA) CO LTD
  • EP4498399A1 patent drawingFigure 1(a)~2
  • EP4498399A1 patent drawingFigure 3~4
  • EP4498399A1 patent drawingFigure 5~6

AI summary

The present disclosure discloses a solid-state circuit breaker, which includes an electronic switch and a mechanical switch connected in series, the mechanical switch comprises: a housing; a handle (2), rotatably installed to the housing and capable of stopping at an on position, an charged position, and an off position between the on position and the charged position; a movable contact (4) and a stationary contact (3), wherein the movable contact is configured to be movable between an open position and a closed position, in the open position, the movable contact is not in contact with the stationary contact, in the closed position, the movable contact is in contact with the stationary contact; and a transmission assembly (5), configured to transmit a motion of the handle to the movable contact to achieve contact and separation with the stationary contact; upon the handle being in the on position, the mechanical switch is on; upon the handle being in the off position, the mechanical switch is off, and the transmission assembly is in a tripping state; upon the handle being in the charged position, the mechanical switch is off, and the transmission assembly is in a non-tripping state.