The carding machine works by opening individual fibers and eliminating impurities of the cotton rolls or the chemical fiber fed by the hopper or the former working process, thus straightening the curly cotton rolls while removing the neps, impurities and short fibers left by the blowing process, and then store the integrated slivers into the cotton cylinder to be used in the drawing process.
The process structure is shown in fig 1.
Fig 1 Flowchart of carding machine
1-Feed roller 2-Feed plate 3-Three taker-in 4-Cylinder 5-Cover 6-Front/back cover
7-Doffer 8-Strip roller 9-Cleaning roller 10-Upper/lower roller 11-Bell mouth 12-Large calender roll
This document takes field requirements for the application of INVT drive as an example, as shown in fig 2. The system requires one 4 kW inverter to control doffer speed and one 0.75 kW inverter to control the feeding of roller. The requirements on the inverter and control performance are listed below:
● Low-frequency and large-torque output, as cylinder inertia is too large, it requires large torque during low-speed startup;
● Quick stabilization at stop;
● Analog output speed regulation, linearize the analog output to the max. extent;
● Stable output voltage and small starting current;
● Good adaptability to the environment, especially to the high temperature and fiber-intensive environment of textile industry;
● Realize compatibility with part of the communication programs by modifying PLC program.
Fig 2 Picture from the field
3.Introduction to INVT GD200A drive
GD200A inverter takes DSP control system as the platform and adopts vectorized V/F control technology as well as multiple kinds of protection modes. It can be applied in asynchronous motor to provide excellent drive performance. It is armed with optimized air duct design, hardware configuration and software functions to improve the usability and adaptability to the environment greatly. GD200A has passed CE certification of TUV SUD and carries the following features:
● Frequency setting mode: Digital / Analog / Pulse frequency / Serial communication / Multi-step speed / Simple PLC / PID; users can switch between the set combination and these modes.
● Accurate motor parameter autotuning: carry out static or rotary motor parameter autotuning accurately, easy commissioning and simple operation, higher control precision and response speed;
● Vectorized V/F control performance;
● Good voltage and current control to reduce inverter protection times
● Provide multiple kinds of brake modes to realize fast stop;
● High over-temperature threshold to fit for textile environment;
● Speed tracking re-start function: start the rotating motor smoothly without impact;
● Automatic voltage regulation function: keep the output voltage constant when grid voltage changes;
● Provide multiple kinds of fault protection functions: overcurrent, overvoltage, undervoltage, over-temperature, phase loss, overload, etc.
4.System wiring and commissioning
The whole system sends running command to the inverter based on the original koyo PLC. GD200A series inverter is compatible with the old-version Modbus-ASCII communication protocol, making it more convenient to modify the communication.
4.1 System commissioning
The commissioning is mainly comprised of the following technical points:
● Smoothness during start/stop;
● High/low speed switching;
● Communication compatibility which is realized by modifying PLC;
- GD200A is set according to the parameters of original Delta inverter;
- Modify PLC program, as GD200A is already compatible with Modbus-ASCII protocol, users just need to modify the frequency address.
- Observe the running effect and smoothness at no-load start/stop
- Loaded pilot run to ensure the process can be done properly
-Observe system stability for a long term.
4.2 Inverter parameter setup
The table below lists some key inverter parameters.
|P00.00||Speed control mode||2|
|P00.01||Running command channel||1|
|P00.03||Max. output frequency||60HZ|
|P00.04||Upper limit of running frequency||60HZ|
|P00.07||Multi-step speed reference||6|
|P00.11||Acceleration time 1||16S|
|P00.12||Deceleration time 1||5S|
|P05.03||Switching between A frequency and B frequency||3|
The market share of Koyo PLC is much less than Simens and Mitsubishi, however, it did capture a certain amount of market share in textile industry. Currently, such devices need to be remodeled as most of the old PLC and communication adopt Modbus-ASCII mode, therefore, GD200A provides some convenience in this respect, and it has improved the over-temperature threshold and temperature pre-alarm function to make it more suitable for textile industry, especially the remodeling market. This inverter is armed with multiple kinds of protections and fault output functions eg short circuit, overload, overvoltage, phase loss and stall protection to ensure the system can run safely and efficiently.
 Operation manual for Goodrive200A inverter by Shenzhen INVT Electric Co., Ltd.