BLDC Motor Torque Monitoring for Thread Lap Detection

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Solution Overview

Problem

Existing thread guiding systems in textile machines face challenges in detecting and preventing unwanted thread windings on godet casings without additional aids, leading to potential yarn breakage and tension issues.

Innovation Solution

Monitoring physical operating parameters of the electric motor, such as operating torque, to identify thread windings by comparing actual values with stored threshold values, and using a friction surface to generate a braking torque for signal amplification, allowing for automatic shutdown and operator notification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a winding sensor with mechanical contact is used to detect thread winding, then thread winding detection is achieved, but additional aids and mechanical complexity are required

Engineering Contradiction:
Improvethread winding detectionVSAvoidadditional detection aids
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electric motor monitors its own operating parameters (torque, current, power) to detect thread windings autonomously, eliminating the need for separate winding sensors. The motor's inherent measurement capabilities are utilized to self-diagnose abnormal conditions caused by thread windings on the godet casing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The detection function is extracted from a separate mechanical winding sensor and integrated into the electric motor's control system. The motor's existing sensors and control electronics are repurposed to detect thread windings, removing the need for additional mechanical detection devices.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a friction roller with limiting means is used to detect thread winding, then thread winding detection is achieved, but additional aids and device complexity are required

Engineering Contradiction:
Improvethread winding detectionVSAvoidadditional monitoring aids
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electric motor autonomously monitors its own torque and power consumption to detect thread windings, eliminating the need for separate friction rollers and limiting means. The motor's inherent capability to measure its operating state enables self-diagnosis of threading anomalies.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The mechanical detection system (friction roller with limiting means) is replaced by an electrical/electronic monitoring system within the motor. The motor's control electronics analyze electrical parameters (current, torque) to detect thread windings, substituting mechanical measurement with electrical measurement.

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

3Adaptability or versatility

If the electric motor power is increased to handle thread variations, then thread guiding capability is improved, but sensitivity to detect small changes decreases

Engineering Contradiction:
Improvethread guiding capabilityVSAvoidpower consumption sensitivity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

Instead of using the motor's full power capacity for thread guiding, the system utilizes the inherent sensitivity of the motor's power consumption measurements to detect small anomalies. The control system monitors partial parameters (torque, current) that are sensitive to minor changes while the motor maintains sufficient overall power for thread guiding tasks.

Inventive Principle:
Principle #16Partial or excessive action

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

Enables the detection and immediate interruption of thread windings without additional tools, ensuring operational reliability and minimizing interruption times in textile processing.

Implementation Method 1

an operating torque of the electric motor is monitored as a physical operating parameter

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a friction surface acts on the thread winding to generate a braking torque acting on the godet sleeve

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3038964B1Method for detecting a thread lap and device for guiding a thread
Publication Date: 2020.07.08 OERLIKON TEXTILE GMBH & CO KG
  • EP3038964B1 patent drawingFigure 1
  • EP3038964B1 patent drawingFigure 2.1
  • EP3038964B1 patent drawingFigure 2.2

AI summary

The invention relates to a method for detecting a thread lap on the circumference of a driven godet jacket (1) of a supplying device and such a supplying device. The method and the supplying device are based on a godet jacket (1) that is driven by a motor shaft (3) of an electric motor (2), on the circumference of which godet jacket a thread is guided. According to the invention, in order to detect the thread lap, a physical operating parameter of the electric motor is continuously monitored, wherein an actual value of the operating parameter is compared with a stored threshold value of the operating parameter. According to the invention, the supplying device has a brushless synchronous motor (BLDC motor) for this purpose, wherein control electronics (5) of the BLDC motor are designed to detect a thread lap formed on the godet jacket (1).