Relay Armature Position Detection Using Dual-Coil Transformer Arrangement

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Solution Overview

Problem

Existing methods for determining the armature position of relays, particularly in compact relay modules, are inadequate for detecting misalignments and faulty contact positions, which can lead to incorrect switching behavior in safety-relevant applications.

Innovation Solution

A multi-coil relay arrangement is used where a first coil and a second coil are mounted on a U-shaped yoke, with a signal transmitter emitting a signal to the first coil and a measuring device detecting a response signal from the second coil to determine the armature position based on transmission properties, such as attenuation or time shifts, allowing for accurate detection of air gap size and misalignments without affecting the relay's operational power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a multi-coil relay arrangement with signal transmitter and measuring device is implemented to determine armature position, then measurement precision of armature position is improved, but device complexity increases

Engineering Contradiction:
Improvearmature position detection accuracyVSAvoidrelay module structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by making the relay coils serve dual purposes: their primary function for relay actuation and a secondary function as transformer windings for position detection. The first and second coils form a transformer arrangement where the first coil acts as primary winding and the second coil as secondary winding, enabling non-contact measurement of armature position through magnetic coupling without requiring separate dedicated sensing components.

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

Solution Approach 2:

The relay module performs self-diagnosis by using its own internal components (coils and magnetic circuit) to detect its operational state. The measuring device evaluates the transmission behavior of magnetic signals through the relay's own magnetic circuit to determine armature position, allowing the system to monitor itself without external complex measurement equipment.

Inventive Principle:
Principle #25Self-service

2Volume of moving object

If compact relay module design with narrow width is used to reduce installation space, then volume of relay module is reduced, but measurement precision of armature position deteriorates

Engineering Contradiction:
Improverelay module sizeVSAvoidair gap measurement accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical position sensing methods with electromagnetic field-based measurement. Instead of using mechanical switches, contactless sensors, or complex mechanical linkages that would require additional space, the system uses magnetic field coupling between the first and second coils to detect armature position. This electromagnetic approach enables accurate measurement within the compact 3-3.5 mm width constraint.

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

Solution Approach 2:

The system changes the measurement parameter from direct physical contact or optical measurement to magnetic field transmission characteristics. By evaluating how magnetic signals transmit through the magnetic circuit and air gap, the system can determine armature position based on changes in magnetic coupling efficiency, which remains effective even in the narrow 3-3.5 mm form factor.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If additional measurement components are added to detect armature position to improve reliability, then reliability of safety function is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvesafety function reliabilityVSAvoidrelay module assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the measurement function with the existing relay structure by integrating the position detection capability into the coil assembly. The first and second coils, already necessary for relay operation, are configured to form a transformer arrangement that simultaneously enables position sensing. This consolidation eliminates the need for separate measurement components and reduces assembly steps while maintaining safety function reliability.

Inventive Principle:
Principle #5Merging (Combining)

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 method enables precise determination of the armature position in limited space, providing a safety function by detecting misalignments and ensuring correct switching behavior in relay modules, even in narrow configurations like those with a width of 3.5 mm, without interfering with the relay's normal operation.

Implementation Method 1

a signal transmitter electrically connected to the first coil and configured to emit a first signal to the first coil, and a measuring device electrically connected to the second coil and configured to detect a second signal at the second coil, the second signal being a response signal to excitation of the first coil with the first signal

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The magnetic transfer behavior between the first and second coils of the relay can depend on the size of the air gap, i.e., the working air gap of the armature, particularly due to the reluctance of the magnetic circuit

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Data Source

PatentEP3667694B1Arrangement for determining an armature position of a relay
Publication Date: 2022.09.28 PHOENIX CONTACT GMBH & CO KG
  • EP3667694B1 patent drawingFigure 1
  • EP3667694B1 patent drawingFigure 2~3
  • EP3667694B1 patent drawingFigure 4

AI summary

The invention relates to an arrangement 100 for determining the armature position of a relay 101, wherein the relay 101 comprises a first coil 103 on a first section 105 of a yoke 102 and a second coil 104 on a second section 106 of the yoke 102, wherein an armature 107 of the relay 101 is spaced from the yoke 102 by an air gap 108. The arrangement 100 includes a signal transmitter 109, which is electrically connected to the first coil 103 and configured to send a first signal to the first coil 103, and a measuring device 110, which is electrically connected to the second coil 104 and configured to detect a second signal at the second coil 104, wherein the second signal is a response signal to an excitation of the first coil 103 with the first signal. The arrangement 100 is configured to determine the armature position of the relay 101 based on the second signal. The invention further relates to a method. (Fig. 1)