State-Indicating Device for Low Current Circuit Breakers

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Solution Overview

Problem

Conventional state-indicating devices for circuit breakers are inadequate for low-voltage and low-current applications, particularly in Programmable Logic Centre (PLC) systems, as they lack a multi-function capability that includes a test function and are not suitable for a wide range of current and voltage levels, especially in Daisy chain applications.

Innovation Solution

A multi-function state-indicating device with a microswitch assembly, mechanical linkage, and test function actuator that allows signal transmission between circuit breakers and indicating devices, enabling On/Off, Signal Default, and combined SD+OF functions, along with a test feature that can actuate microswitches without switching the circuit breaker, using precision snaps and mechanical connections for interaction and status sharing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional state-indicating device is used for high current applications, then it can indicate trip status for high current and voltage, but it cannot be applied to low current and voltage PLC applications

Engineering Contradiction:
Improvecurrent and voltage operating rangeVSAvoiddevice design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The state-indicating device is designed with a universal mechanical linkage system that can indicate trip status across multiple current and voltage ranges. The device incorporates adjustable components and multiple operating modes that allow it to function in both high current/voltage and low current/voltage PLC applications, eliminating the need for separate devices for different applications.

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

2Reliability

If a test function is added to the state-indicating device, then fault detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoiddevice structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The test function is integrated into the existing mechanical linkage system of the state-indicating device. The test mechanism shares common components with the trip indication mechanism, such as the mechanical plate, lever, and microswitch assembly. This merging of functions allows fault detection capability to be enhanced without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a mechanical linkage system is used to transmit trip status, then reliable status indication is achieved, but the device size and mechanical complexity increase

Engineering Contradiction:
Improvestatus indication reliabilityVSAvoiddevice volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The mechanical linkage components are arranged in a compact, nested configuration within the device housing. The mechanical plate, lever, and microswitch assembly are positioned to utilize available space efficiently, with each component fitting within or alongside the others. This nesting approach maintains reliable mechanical status transmission while minimizing the overall device volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4270438B1State-indicating device for low current applications with wider operating range
Publication Date: 2024.10.16 SCHNEIDER ELECTRIC IND SAS
  • EP4270438B1 patent drawingFigure 1
  • EP4270438B1 patent drawingFigure 2
  • EP4270438B1 patent drawingFigure 3

AI summary

The present invention relates to a state-indicating device (100) for circuit breaker with test function disclose. The state-indicating device (100) includes signal transmission to plurality of indicating devices (100) from the circuit breaker by means of linking features between the circuit breaker and indicating device and also linkage between one indicating device and other indicating device. Indicating device includes a mechanical linkage comprising an actuator connected to hook member (7) and tripping bar (8) with stainless-steel rod (9) being configured to: operate mechanical plate (6) and lever (10), test function actuator (4); to push the microswitch button (19) of a microswitch assembly (12) by selectively On/Off (OF), Signal Default (SD) and SD+OF causing the circuit to change status from Normally Open (NO) to Normally Close (NC); and to show the trip status of the circuit breaker which is mounted to, say the right side of the invented state-indicating device (100).