Electromagnetic Actuator Current Analysis for Switch Degradation Detection

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Solution Overview

Problem

Existing low- and medium-voltage switching devices, such as circuit breakers, face challenges in monitoring the degradation of their electromagnetic actuators due to aging, which can lead to safety risks and operational failures without effective real-time diagnostic methods.

Innovation Solution

A method is proposed to detect degradation in electromagnetic actuators by measuring current flow, determining reaction time and current values, and analyzing these parameters through a polynomial to identify fluctuations, allowing for early detection of potential faults without additional sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If real-time diagnosis of electromagnetic actuator condition is implemented, then reliability of switching device is improved, but device complexity increases due to additional measuring circuits and diagnostic systems

Engineering Contradiction:
Improveelectromagnetic actuator condition monitoringVSAvoidmeasuring circuits and diagnostic systems
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electromagnetic actuator monitors its own condition by utilizing its existing control coil and measuring the current that flows through it during normal operation. The microcontroller analyzes this self-generated current data to detect degradation, eliminating the need for separate diagnostic actuators or external monitoring equipment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control coil serves dual purposes: it functions as the electromagnetic actuator component that drives the mechanical switch, and simultaneously serves as the sensor for monitoring the actuator's health condition. This multi-functionality reduces the need for additional dedicated monitoring components.

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

2Measurement precision

If additional sensors are added to monitor actuator degradation, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveactuator condition detection accuracyVSAvoidsensor quantity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the actuator's own operating current as the measurement parameter. By analyzing how the current changes during actuation cycles, the system precisely detects degradation without requiring external sensors attached to the moving parts or magnetic field sensors.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The microcontroller acts as an intermediary that transforms ordinary current measurements into precise degradation indicators. Through signal processing and comparison of current waveforms across multiple cycles, it extracts meaningful diagnostic information from standard electrical measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method enables robust, real-time detection of electromagnetic actuator degradation, facilitating timely maintenance and preventing operational failures by quantifying the severity of degradation through statistical parameters.

Implementation Method 1

The electromagnetic actuator comprises a movable magnetic core and a control coil. Under the influence of an electric current flowing through the control coil, the magnetic core moves.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

measure a current flowing through the electromagnetic actuator when the electromagnetic actuator is controlled

Methodology Applied
Scientific EffectElectrical resistance measurement: Electrical Resistance

Data Source

PatentEP4492422B1Method for detecting a degradation of a switching device having an electromagnetic actuator
Publication Date: 2025.11.12 SCHNEIDER ELECTRIC IND SAS
  • EP4492422B1 patent drawingFigure 1
  • EP4492422B1 patent drawingFigure 2
  • EP4492422B1 patent drawingFigure 3

AI summary

A method is proposed for detecting a degradation of a switching device (30) comprising an electromagnetic actuator (1) configured to unlock a control mechanism (4) comprising an elastic element (7), the method comprising the steps: (i) controlling the electromagnetic actuator (1), (ii) measuring a current (C) flowing in the electromagnetic actuator (1), (iii) determining from the measured current (C) a reaction time (ta) of the electromagnetic actuator (1), (iv) determining from the measured current (C) a quantity (i1) representative of the current flowing in the electromagnetic actuator (1), (v) determining a parameter (P) in the form of a polynomial of the determined reaction time (ta) and the determined quantity (i1) representative of the current flowing in the electromagnetic actuator (1),(vi) iterate steps (i) to (v) for a set of successive commands of the electromagnetic actuator (1) so as to obtain a set (E) of values ​​of the determined parameter (P), (vii) determine a degradation of the electromagnetic actuator (1) from the evolution of the values ​​of the set (E) during the successive commands of the electromagnetic actuator (1).