Residual Load Disconnect Switch with Load Detection Interlock

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Solution Overview

Problem

Existing disconnect switches for rail vehicles are not optimally designed, requiring significant manual force for operation, posing a risk of electric shock and potential accidents due to incorrect switch activation under residual load, and do not effectively prevent opening under main load conditions, which can lead to dangerous residual currents.

Innovation Solution

A residual load disconnect switch with a rotary snap-action drive and load detection system that allows remote, unidirectional operation, ensuring safe activation only when residual load criteria are met, featuring a compact design and integrated arc extinguishing chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a disconnect switch is operated manually under main load conditions, then the electrical connection can be disconnected, but it causes dangerous residual currents and potential switch destruction

Engineering Contradiction:
Improvesafe disconnectionVSAvoidresidual current danger
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The load detection system performs preliminary checking of load conditions before allowing switch operation. The control unit detects whether residual load is below the threshold value before enabling the disconnect switch, preventing dangerous operations under main load conditions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the electrical load through detection devices and provides feedback to the control unit. This feedback mechanism ensures real-time awareness of load conditions, enabling safe operation decisions and preventing residual current dangers

Inventive Principle:
Principle #23Feedback

2Power

If a disconnect switch is designed for high current carrying capacity, then it can handle main load currents, but it requires significant manual force for operation

Engineering Contradiction:
Improvecurrent carrying capacityVSAvoidmanual operation force
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical operation with an automated drive mechanism controlled by a control unit. The disconnect switch is actuated through electrical or automated mechanical means, eliminating the need for significant manual force while maintaining high current carrying capacity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The disconnect switch system performs self-operation through automated detection and actuation. The control unit automatically detects load conditions and triggers the drive mechanism to open or close the switch without requiring manual intervention, making the system self-sufficient

Inventive Principle:
Principle #25Self-service

3Reliability

If load detection and control systems are added to prevent residual load disconnection, then switching safety is improved, but device complexity increases

Engineering Contradiction:
Improveswitching safetyVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit performs multiple functions including load detection, threshold comparison, operation control, and status monitoring within a single integrated component. This multi-functionality reduces the need for separate dedicated devices for each function, thereby limiting the increase in overall system complexity

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

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

Enables safe, remote, and efficient disconnection of residual loads without manual intervention, reducing the risk of accidents and ensuring reliable switching behavior, while minimizing switch dimensions and weight.

Implementation Method 1

A residual load disconnect switch (1) with a rotary snap-action drive (40) is disclosed, which enables an iterative, sudden rotation in always the same direction of rotation

Methodology Applied
Scientific EffectSpring energy storage and release: Spring

Implementation Method 2

The jump drive (40) is configured to cause the rotary switching element (23) to perform an abrupt switching rotation

Methodology Applied
Scientific EffectMechanical energy accumulation: Mechanical Accumulator

Implementation Method 3

integrated arc extinguishing chambers

Methodology Applied
Scientific EffectArc extinction: Electric Arc

Data Source

PatentEP4212386B1Operating method for a residual load disconnecting switch
Publication Date: 2026.01.28 WALTER KRAUS
  • EP4212386B1 patent drawingFigure 1~2
  • EP4212386B1 patent drawingFigure 3~4
  • EP4212386B1 patent drawingFigure 5

AI summary

The invention relates to an operating method for a residual load disconnect switch (1) which has a load detection feature that monitors current flow and/or voltage between the supply terminal (20) and the discharge terminal (21) of the residual load disconnect switch (1). The method comprises the following steps: receiving a request to disconnect the electrical connection at the residual load disconnect switch (1); checking a load applied to the residual load disconnect switch between the supply terminal (20) and the discharge terminal (21); if it is determined that the load applied to the residual load disconnect switch between the supply terminal (20) and the discharge terminal (21) is less than a permissible residual load: triggering the abrupt rotational movement of the rotary switching element.The operating procedure achieves improved remote controllability in various respects and enables safe operation of the disconnect switch, which avoids the risk of electric shock to a worker and thus reduces the risk of accidents.