LVDT Core Fallout Detection via Voltage Ratio Analysis

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Linear variable differential transformers (LVDTs) in process control systems can experience core fallout conditions, leading to incorrect control signals and potential damage or safety hazards if not detected, as existing monitoring systems are inadequate in identifying this failure mode.

Innovation Solution

A method and apparatus that measure voltages across LVDT sensing coils, signaling a core fallout condition based on specific voltage ratios and sums, allowing for timely detection and corrective action.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing monitoring systems are used to monitor LVDT operation, then general sensor monitoring is provided, but core fallout conditions cannot be detected

Engineering Contradiction:
Improvedetection capabilityVSAvoidfailure detection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the monitoring parameters from general voltage level monitoring to specific ratio-based monitoring. By calculating the ratio between voltages from different sensing coils and comparing it against expected ranges, the system can specifically detect core fallout conditions that general monitoring would miss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical/core-physical monitoring with electrical field-based voltage ratio analysis. Instead of monitoring physical core position directly, the system uses electrical measurements from sensing coils to infer core status, enabling detection of fallout conditions through electrical parameter analysis.

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

2Productivity

If LVDT core fallout is not detected, then the system continues operation, but incorrect control signals are provided leading to damage or safety hazards

Engineering Contradiction:
Improvecontinuous operationVSAvoiddamage and safety hazards
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary detection of core fallout conditions through voltage ratio monitoring before the system can generate incorrect control signals. By continuously monitoring the voltage ratio and comparing it to expected ranges, the system identifies core fallout early, allowing preventive action before damage occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback monitoring where voltage measurements from sensing coils are continuously processed to calculate ratios, which are then compared against expected ranges. This closed-loop feedback system provides continuous verification of core status, enabling real-time detection of fallout conditions that would otherwise go undetected.

Inventive Principle:
Principle #23Feedback

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

Effectively detects LVDT core fallout conditions, preventing damage and ensuring safety by providing accurate control signals and enabling prompt maintenance in process control systems.

Implementation Method 1

Linear variable differential transformers (LVDTs) are electro-mechanical transducers widely used to measure position or displacement

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2707731B1Method and apparatus for detection of LVDT core fallout condition
Publication Date: 2016.03.30 HONEYWELL INTERNATIONAL INC
  • EP2707731B1 patent drawingFigure 1~3
  • EP2707731B1 patent drawingFigure 4~5
  • EP2707731B1 patent drawingFigure 6

AI summary

A method includes measuring a first voltage (VA) across a first sensing coil of a linear variable differential transformer (LVDT) and measuring a second voltage (VB) across a second sensing coil of the LVDT. The method also includes signaling a core fallout condition in response to (i) determining that a ratio of VA and VB is within a specified range of a value of one and (ii) determining that a sum of VA and VB is less than a sum of VA0 and VB0 by more than a specified amount. VA0 and VB0 are minimum voltages across the first and second sensing coils of the LVDT, respectively, when a core of the LVDT is in the LVDT.