Weaving Machine Start-Up via Shedding Machine Overspeed Energy Feedback
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Solution Overview
Problem
Weaving machines experience power peaks during start-up, leading to voltage dips and potential shutdowns, especially in weak electrical supply networks, resulting in reduced weaving speed and quality issues due to inefficient kinetic energy feedback from shedding machines.
Innovation Solution
The method involves starting the shedding machine at an overspeed and adjusting its speed reduction profile to provide greater energy feedback towards the end of the start-up phase, matching the weaving machine's energy requirements while maintaining voltage limits, using a computing unit to calculate optimal speed profiles based on machine and process data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the weaving machine is started at full working speed using direct electric drive, then the start-up time is reduced and productivity is improved, but voltage dips occur in weak electrical networks causing start-up failures
Solution Approach 1:
The shedding machine is pre-accelerated to an overspeed before the weaving machine starts, so that kinetic energy is stored and can be fed back during the critical start-up phase to support the weaving machine without causing voltage dips
Solution Approach 2:
The drives of the weaving machine and shedding machine are connected through a common DC intermediate circuit, allowing kinetic energy from the shedding machine to be transferred to support the weaving machine start-up
2Power
If the shedding machine provides kinetic energy feedback during weaving machine start-up, then peak power requirements are reduced, but uniform deceleration causes excessive voltage rise requiring energy dissipation in braking resistors
Solution Approach 1:
The shedding machine's speed profile is dynamically adjusted with a non-uniform deceleration curve, where the deceleration rate increases progressively during the start-up phase, matching the weaving machine's increasing energy demand and avoiding excessive voltage rise that would require braking resistor dissipation
Solution Approach 2:
The deceleration parameter of the shedding machine is changed from uniform to non-uniform, with the gradient of speed reduction increasing over time to optimize energy feedback timing and amount
3Reliability
If the weaving machine starts at reduced speed to avoid voltage dips, then start-up reliability is improved, but starting marks appear in the fabric and quality deteriorates
Solution Approach 1:
The shedding machine acts as an intermediary energy source, providing kinetic energy feedback to the weaving machine during start-up, enabling the weaving machine to accelerate to full working speed without causing voltage dips that would force a speed reduction
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 approach reduces peak power requirements, ensures reliable start-up dynamics, and minimizes energy losses, allowing for consistent operation without compromising weaving speed or quality.
Implementation Method 1
the sheath-forming machine releases kinetic energy by decelerating again to support its start-up
Implementation Method 2
the drives of the weaving machine and the sheet forming machine are connected by means of a common DC intermediate circuit, hereinafter referred to as the converter intermediate circuit, so that they can form an energy flow between each other
Data Source
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AI summary
The invention relates to a method for controlled start-up of a weaving and shedding machine, wherein: - the weaving machine and the shedding machine are connected to a control device, - the weaving machine is driven by means of a main drive; - the shedding machine is driven by means of an electric motor auxiliary drive; - the weaving machine and the shedding machine are connected to the energy flow transmission by means of a common converter D.C. link, - the shedding machine is started at a time t0 and accelerated up to a time t1 to an overspeed which is above its working speed, wherein the time t1 is before a time t3; - the weaving machine is started at a time t2, wherein the start phase of the weaving machine is within the time interval from time t2 up to time t3; and - a power transmission (feeding back) is carried out from the shedding machine to the weaving machine in the said start phase by means of the converter D.C. link. The method according to the invention is characterised in that the shedding machine is accelerated to a specified overspeed between the times t0 and t1, and in that the gradient of the rotational speed curve of the shedding machine is more negative in a later section of the start phase than in an earlier section.