In spring season, the domestic covid 19 has just ended, the global foreign covid 19 is intensifying, and the global shortage of epidemic prevention materials has caused, the price Meltblown Fabric fluctuate greatly. The demand for meltblown fabrics is needed all the world
1. Meltblown Fabric , Everyone is familiar
Meltblown Fabric : The "heart" of the mask，the key material for the mask. It uses polypropylene as the main raw material and the fiber diameter can reach 0.5-10 microns. One ton of Meltblown Fabric ,on the market can be used for 1 million medical surgical masks.
The production process of melt-blown cloth is shown in the following figure:
In this process, the melt is extruded from the spinneret hole, the main motor equipment is a single screw extruder. As shown below:
2. Load characteristics of screw extruder and selection of frequency converter
According to the process accuracy requirements of processing different products, the control modes that can be selected by the inverter include V / F control, speed sensorless vector control, and vector + PG control mode.
An extrusion equipment is usually composed of a host, an auxiliary machine and a control system.
①. Host
The main machine is composed of three parts: extrusion, transmission and heating and cooling.
②. Auxiliary machine
The composition of the auxiliary machine depends on the type of product. Generally , the auxiliary machine is composed of agent through setting device, cooling device, traction device, cutting device, and product winding or stacking device.
③. Control system
The control system is mainly composed of frequency converters, low-voltage electrical appliances, display instruments and actuators.
Inverter selection: Use constant torque general-purpose (G-type) inverter, select the inverter specifications according to the nameplate current of the motor and the maximum load when processing different materials, generally the operating current does not exceed the inverter The rated current.
3. Site conditions and customer requirements
The screw extruder is a constant torque load, so the inverter is selected as PI500 / PI500A series and PI150 series (maximum 5.5kW), the input voltage of the inverter is 380V ± 15%, and the rated output power is 11kW ~ 22KW.
4. Inverter parameter setting：
Motor group parameters:
|
Code |
parameter name |
description |
setting |
|
b0.00 |
Motor type selection |
Ordinary asynchronous motor |
0 |
|
b0.01 |
rated power |
0.1~1000.0KW |
30 |
|
b0.02 |
rated voltage |
1V~2000V |
380 |
|
b0.03 |
rated current |
0.011A~655.35A |
56.8 |
|
b0.04 |
rated power |
0.01HZ~F0.10（Max power） |
50 |
|
b0.05 |
rated speed |
1rpm~36000rpm |
1470 |
|
b0.27 |
Self-learning options |
Asynchronous motor parameter static self-learning |
1 |
Operating parameters:
|
Code |
parameter name |
description |
setting |
|
F0.00 |
Motor control method |
V/F control |
2 |
|
F0.11 |
Command source selection |
terminal control |
1 |
|
F0.03 |
Frequency source master setting |
Analog AI1 setting |
2 |
|
F0.13 |
acceleration time 1 |
0.01~36000s |
15 |
|
F0.14 |
deceleration time |
0.01~36000s |
15 |
|
F4.11 |
Oscillation suppression gain |
0~100 |
30 |
|
F1.00 |
DI1 Terminal function selection |
Forward run(FWD) |
1 |
|
F2.07 |
DA1 Output function selection |
Output current |
2 |
|
F2.08 |
DA2 Output function selection |
Motor speed |
13 |
|
F3.07 |
Stop mode |
Free parking |
1 |
5. On-site debugging operation
After setting the inverter parameters, follow the steps below to debug:
①. First run at low speed of 5Hz, observe the motor start, stop and run smoothly, the output voltage of the inverter is three-phase balanced, the output current is 22A, and the current fluctuation is less than 1A
②. When the frequency is up to 15Hz, the motor starts, stops and runs smoothly, the output voltage of the inverter is stable, the current is 20A, the current fluctuation is within 1A, and the motor has no vibration.
③. The frequency rises to 30Hz, the motor runs smoothly, the output voltage of the inverter is stable, the current is 20A, the current fluctuation is within 1A, and the motor has no vibration.
After the above steps of commissioning and operation, the user is very satisfied with the use of the inverter and fully meets the previous requirements of the customer. Officially started production, the product quality also fully meets the standard requirements. A total more than 200 units inverter delivery this time.
Experiments prove that PI500A series and PI150 series inverters have excellent performance and rich functions. They are very well used in screw extruders and can be promoted in the industry.
