Relay Switch State Detection via Core Permeability

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Solution Overview

Problem

Existing methods for determining the switching state of electromechanical relays, especially in small-sized devices, are cumbersome and unreliable due to the need for extensive sensor arrangements, which complicates safe and reliable status detection.

Innovation Solution

A method that measures and evaluates the relative change in core permeability using oppositely polarized test pulses, allowing for direct electronic detection of the switching state within the relay's housing, minimizing external components and ensuring reliability and convenience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external sensors (magnetic, optical, or capacitive) are used to detect the switching state, then the switching state can be determined non-contactly, but the device complexity and equipment outlay increase significantly

Engineering Contradiction:
Improveswitching state detection reliabilityVSAvoidsensor arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from external sensors and relocates it inside the relay housing. The evaluation unit is integrated within the housing to evaluate the switching state based on magnetic field changes, eliminating the need for complex external sensor arrangements while maintaining reliable detection capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the detection and evaluation functions into the relay housing itself. The evaluation unit is merged with the existing relay structure, allowing the switching state to be determined using the relay's own magnetic field characteristics without requiring separate external sensing systems.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If multiple external sensors are arranged to detect the switching state, then detection coverage is improved, but the construction becomes less safe and reliable

Engineering Contradiction:
Improveswitching state detection precisionVSAvoidconstruction safety and reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The relay uses its own magnetic field characteristics to detect its switching state. The evaluation unit within the housing evaluates changes in magnetic field strength caused by the armature position, allowing the relay to self-diagnose its state without external interference or additional sensing components that could compromise reliability.

Inventive Principle:
Principle #25Self-service

3Device complexity

If external capacitive coupling is used to detect switching states, then the detection method is simplified, but the method is not practicable for small-sized relays

Engineering Contradiction:
Improvedetection circuit complexityVSAvoidapplicability to small-sized relays
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent replaces external capacitive coupling with an internal magnetic field-based detection system. The evaluation unit measures changes in magnetic field strength directly within the housing, a method that scales effectively to small-sized relays without requiring large external coupling capacitors or complex external circuitry.

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

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

This approach provides a reliable, efficient, and cost-effective means to determine the switching state of electromechanical relays, suitable for both manual and electrically controlled changes, with minimal impact on the relay's physical parameters, and is applicable to both single-coil and double-coil systems.

Implementation Method 1

at least one permanent magnet, at least one magnetically excitable coil

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

a soft-magnetic armature mounted in the coil so that it can rotate between two end positions

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Implementation Method 3

when the armature changes between the two end positions, the core permeability changes and the respective magnetic working point is shifted

Methodology Applied
Scientific EffectCore permeability change: Magnetic Hysteresis

Data Source

PatentEP2181456B1Method for detecting of a switch state
Publication Date: 2011.10.26 MERTEN GMBH & CO KG
  • EP2181456B1 patent drawingFigure 1
  • EP2181456B1 patent drawingFigure 2
  • EP2181456B1 patent drawingFigure 3

AI summary

The invention pertains to a method for detecting of a switch state in an electromechanical switching unit, wherein at least one permanent magnet (1), at least one magnetically excitable coil (2), one soft magnetic armature (3) seated in the coil (2) so as to rotate between two end positions (A, B) and being connected to at least one switch contact, and additional electrical components (9) are arranged in a housing, and wherein during a change in the armature (3) between the two end positions (A, B) the core permeability is changed and the particular magnetic working point is shifted. In order to create a method for detection of the switch state of an electromechanical switching unit which is convenient and reliable, and in particular which can be used in small-size relays, core permeabilities of the system are measured and evaluated to determine the switch state of the switching unit.