Contactor Coil Diagnostics for Sensorless Core Position Tracking
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Solution Overview
Problem
Existing methods for diagnosing the wear state of electrical contactors, such as those using position sensors or magnetic flow variations, are not precise enough to accurately assess contactor wear, making it difficult to determine the condition of electrical contacts and plan maintenance effectively.
Innovation Solution
A diagnostic process that measures coil current and voltage values during the closing phase of an electromagnetic actuator, calculates magnetic flow, and uses a data table to determine the position of the actuator's nucleus, allowing for precise tracking of the actuator's movement without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is integrated into the electromagnetic actuator to directly measure displacement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical position sensor with an electrical measurement system. By measuring coil current and voltage and calculating magnetic flux, the system derives core position information without physical sensors. This substitution eliminates the need for additional mechanical components while maintaining measurement capability.
Solution Approach 2:
The patent introduces magnetic flux as an intermediary parameter. Instead of directly measuring position, the system measures coil electrical parameters (current and voltage), calculates magnetic flux, and then determines core position from the flux value. This intermediary approach enables indirect but accurate position measurement without physical contact sensors.
2Device complexity
If magnetic flux variation is used to evaluate actuator states, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where coil current and voltage measurements are continuously monitored, magnetic flux is calculated from these measurements, and core position is determined from the flux value. This closed-loop feedback system enables precise position tracking by constantly updating the position information based on real-time electrical parameter measurements.
Solution Approach 2:
The patent performs preliminary calibration by establishing the relationship between magnetic flux and core position before actual measurement. The system pre-determines how flux values correspond to specific positions, enabling accurate position calculation during operation without requiring complex real-time computations.
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 process provides accurate and economical assessment of contactor wear by precisely tracking the nucleus position and movement during the closing phase, enabling reliable monitoring of contactor condition and maintenance planning.
Implementation Method 1
the movable part of the actuator which moves under the effect of a magnetic field created by the coil when it is traversed by an adequate electric current
Implementation Method 2
calculating and recording values of a magnetic flux passing through the coil, by integrating the recorded values of the coil current, the coil voltage and the resistance and inductance values of the coil
Data Source
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AI summary
Method for diagnosing the operating state of a switching device comprising separable contacts, controlled by an electromagnetic actuator comprising a coil connected to an electronic control device, and sensors, configured to measure the intensity of a coil current and a coil voltage.The method includes the steps of: a) receiving (102) a closing command by the electronic control device; b) commanding (104) the closing of the electromagnetic actuator; c) measuring and recording (106) the coil voltage and coil current values; d) calculating and recording (112) values of a magnetic flux through the coil, by integrating the recorded values of the coil current, the coil voltage and the resistance and inductance values of the coil; e) evaluating and recording (114) positions of a core of the electromagnetic actuator according to a data table, which is previously recorded in the electronic control device and which defines a bijective relationship between the position of the core, the magnetic flux and the coil current.