Earthing Disconnector Mode Selector with Cam Interlocks

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Solution Overview

Problem

Current high voltage earthing switches face complexity in operation due to the superposition of manual and motorized steps, failing to maintain mechanical and electrical interlocks, and ensuring safe lockout conditions, especially in case of failures like welded contacts or control shaft breakage.

Innovation Solution

A control system with an operating mode selector that integrates mechanical and electrical interlocks, using cams and levers to manage different operating modes, ensuring safe operation by maintaining mechanical safety devices alongside electrical safety, and preventing unintended disconnector operation through mechanical motor interlocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If motorization is added to manual earthing disconnectors for remote control, then operator safety is improved by keeping the operator away from potential internal arcs, but operational complexity increases due to interactions between manual and motorized modes

Engineering Contradiction:
Improveoperator exposure to internal arcVSAvoidoperational complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and separates the control functions into distinct operational modes (manual and motorized) that are mutually exclusive. The selector switch isolates the motorized control circuit from manual operation, preventing simultaneous activation and simplifying the operational logic despite having both control methods available.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system dynamically switches between manual and motorized operating modes based on the position of the selector switch. This dynamic reconfiguration allows the system to adapt its control mechanism while maintaining clear separation between modes, managing complexity through flexible yet distinct operational states.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If electrical interlocking system is added for motor control, then remote operation capability is improved, but reliability decreases because mechanical interlocks are not maintained

Engineering Contradiction:
Improveremote operation capabilityVSAvoidinterlock maintenance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent merges electrical and mechanical interlocking systems into a unified control architecture. The selector switch simultaneously controls both the electrical interlock (preventing motor operation in certain positions) and maintains mechanical interlock integrity, ensuring that both systems work together rather than independently, thereby maintaining reliability while enabling remote operation.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If selector allows both manual and motorized operation, then operational versatility is improved, but safety decreases due to potential conflicts between operating modes

Engineering Contradiction:
Improveoperational versatilityVSAvoidoperational safety
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The selector switch acts as an intermediary mechanism that mediates between manual and motorized operation modes. It provides a clear, physically distinct switching mechanism that prevents direct conflict between modes by requiring explicit operator action to change modes, thereby maintaining safety while enabling versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The operational modes are segmented into distinct, non-overlapping states controlled by the selector switch. Each mode (manual, motorized, locked open, locked closed) is clearly separated and mutually exclusive, preventing ambiguous or conflicting operations while maintaining the ability to switch between different operational requirements.

Inventive Principle:
Principle #1Segmentation

4Reliability

If mechanical interlocks are maintained during motorized operation, then reliability is improved by ensuring interlocks are always active, but device complexity increases

Engineering Contradiction:
Improveinterlock continuityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The selector switch performs multiple functions simultaneously: it selects operating modes, controls electrical interlocks, and coordinates with mechanical interlock systems. This multi-functionality allows the same component to maintain interlock continuity across different operational modes without adding separate dedicated mechanisms for each function, thereby managing complexity while ensuring reliability.

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

Enhances safety for personnel and equipment by ensuring all interlocks are maintained across modes, preventing accidental operation and ensuring the earthing switch remains in a safe state even during failures, thus increasing operational safety and reliability.

Implementation Method 1

a cam system C, the role of which will be explained later

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP3322052B1Selector of the operation of a grounding switch
Publication Date: 2023.03.29 SCHNEIDER ELECTRIC IND SAS
  • EP3322052B1 patent drawingFigure 1~2a
  • EP3322052B1 patent drawingFigure 2b~2d
  • EP3322052B1 patent drawingFigure 3~5

AI summary

Selector (2) for operating mode of an earthing disconnector (1), the earthing disconnector comprising power contacts (10) and a motor (24) for operating the power contacts (10), the selector comprising a plurality of positions corresponding respectively to different operating modes of the earthing disconnector, and comprising cams whose position is defined by the position of the selector, characterized in that the selector comprises a first cam which drives a first locking member (27) intended to mechanically block the motor of the earthing disconnector when the selector is in a position of the plurality of positions corresponding to a locked closed mode in which the earthing disconnector is closed.