Residual Current Circuit Breaker Test Circuit Protection

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Solution Overview

Problem

Circuit breakers from prior art leave the test circuit active after a mechanical opening or differential fault, allowing unnecessary current flow and potentially damaging the test function due to prolonged button pressing.

Innovation Solution

Incorporation of a second switch in the test circuit that can be opened by the connecting piece when the breaking compartments are open or a differential fault is detected, ensuring the test circuit is deactivated to prevent short circuits and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the test circuit remains active after mechanical opening or differential fault, then the test function remains accessible, but unnecessary current flows and the test function may be damaged due to prolonged button pressing

Engineering Contradiction:

Improvetest function protectionVSAvoidunnecessary current flow

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The connecting piece is positioned in advance to automatically open the second switch when the breaking compartments open or a differential fault occurs, preventing unnecessary current flow and potential damage before they can occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the state of the breaking compartments (open/closed) and differential protection status as feedback signals to automatically control the second switch, ensuring the test circuit is deactivated when inappropriate for testing

Inventive Principle:

Principle #23Feedback

2Reliability

If a second switch is added to deactivate the test circuit, then the test function is protected from damage, but the device complexity increases

Engineering Contradiction:

Improvetest function protectionVSAvoidtest circuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The connecting piece serves multiple functions: it mechanically connects the breaking compartments, actuates the opening of contacts during differential faults, and now also controls the second switch to protect the test circuit, eliminating the need for separate dedicated components

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control function for the second switch is merged into the existing connecting piece mechanism, so that the same component that manages mechanical connection and fault actuation also manages test circuit protection, reducing overall device complexity despite adding the second switch

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP3029704B1Differential circuit breaker

Publication Date: 2021.03.31 HAGER ELECTRO SAS

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AI summary

The present invention relates to a residual current circuit breaker (210) comprising at least one breaking compartment, a residual current protection compartment, and a connecting piece (250) mounted inside the residual current protection compartment. The breaking compartment(s) have a mechanism for opening and closing at least one electrical contact between an upstream and a downstream electrical line. The residual current circuit breaker further comprises a test circuit for testing the proper operation of the residual current protection compartment. This test circuit includes a first switch (220) that can be opened and/or closed by pressing a test button (222). The test circuit also includes a second switch (230) that can be opened by the connecting piece (250) when the contact of the breaking compartment(s) is/are open and/or when the residual current protection compartment detects a fault.