Damping Element for Residual Current Circuit Breaker Plunger Reset

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Solution Overview

Problem

Electromechanical protective switching devices, such as residual current circuit breakers, face challenges with low tripping force and sensitivity to shocks and vibrations, leading to potential false releases and reduced tripping accuracy due to the dynamic reset movement damaging the tripping relay.

Innovation Solution

An electromechanical protective switching device with an insulating housing and an electromechanical tripping relay featuring a plunger that uses a damping element to gently return to its rest position, reducing the risk of damage and maintaining high tripping accuracy over the service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a resetting device is used to return the plunger to its rest position, then the protective switching device can be reset after tripping, but the dynamic reset movement can damage the tripping relay and cause false releases

Engineering Contradiction:
Improveresetting capabilityVSAvoidtripping accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by introducing a damping element that is pre-positioned to absorb the impact when the plunger returns to its rest position. The damping element is designed to engage with the plunger during the reset movement, cushioning the impact before it can damage the tripping relay or cause false releases. This resolves the contradiction by enabling reliable resetting while protecting the tripping accuracy through advance impact absorption.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Measurement precision

If the tripping relay is designed with high sensitivity to detect residual currents, then fault detection capability is improved, but the device becomes more susceptible to false releases from shocks and vibrations

Engineering Contradiction:
Improveresidual current detection accuracyVSAvoidsensitivity to shocks and vibrations
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies the intermediary principle by introducing a damping element as a mediator between the plunger and the external environment. This damping element absorbs and attenuates shocks and vibrations before they can reach the sensitive tripping relay components, thereby protecting the high-sensitivity detection system from false releases while maintaining its ability to detect actual residual current faults.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If the base body is moved quickly to reset the plunger, then the resetting speed is improved, but the impulse transmitted to the plunger increases and may cause damage

Engineering Contradiction:
Improveresetting speedVSAvoidimpulse on plunger
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The patent applies beforehand cushioning by positioning the damping element to engage with the plunger during the reset movement. Even though the base body moves quickly to achieve fast resetting, the damping element is already in place to absorb and reduce the impulse transmitted to the plunger, thereby maintaining high resetting speed while preventing damage from excessive force.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 damping element effectively reduces the impulse transmitted to the plunger, minimizing the risk of damage and ensuring consistent tripping accuracy throughout the device's service life by providing a controlled and gentle reset mechanism.

Implementation Method 1

The damping element is designed to be elastic in such a way that the impulse of the base body acting on the plunger is damped as a result

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3537466B1Electromechanical protective switching device
Publication Date: 2022.06.01 SIEMENS AG
  • EP3537466B1 patent drawingFigure 1~3
  • EP3537466B1 patent drawingFigure 4
  • EP3537466B1 patent drawingFigure 5

AI summary

The electromechanical protective switching device (1) according to the invention, which is designed in particular as a residual current circuit breaker, has an insulating housing (2) and an electromechanical trip relay (20) which is received and held in the insulating housing (2) and which in turn has a plunger (21) that is movably mounted between a trip-ready rest position and a tripped position. Furthermore, the protective switching device (1) has a reset device (30) for returning the plunger (21) to the trip-ready position. The reset device (30) has a base body (31) movably mounted in the insulating housing (2), to which a damping element (32) is attached. This damping element is designed to act on the plunger (21) when the base body (31) moves, in order to return the plunger to the trip-ready position.The damping element (32) is designed to be elastic in such a way that it dampens the impulse of the base body (31) acting on the plunger (21). This allows for a smooth return of the plunger (21), which significantly reduces the risk of damage to the sensitive trip relay (20). Thus, a consistently high tripping accuracy can be achieved throughout the service life of the protective switching device (1).