Wire drawing machine is an important equipment in metal wire processing, which belongs to impact load. Its production quality and efficiency are very important for enterprises. There are three types of wire drawing machines: air pulley, looper and linear. With the development of production technology, AC frequency conversion technology and PLC program control in electrical control have gradually replaced DC motors and torque motors, and established a dominant position.
1. The requirements of the wire drawing machine for the frequency converter
(1) The starting torque of up to 150% is required when the frequency converter is 0.5HZ.
(2) It is required to be able to realize the proportional intermodal control of multiple units, and to automatically adjust the output frequency to keep the speed constant as the load and voltage change.
(3) There must be RS485 communication function and PLC and PC to realize communication control.
(4) It is controlled by common DC bus, and the power saving effect is good.
2. Disadvantages of the traditional V/F control or space vector control inverter
(1) The traditional V/F inverter has low frequency and insufficient torque.
(2) When the load and voltage fluctuate, the speed will be unstable, so high-precision proportional linkage control cannot be achieved. Only non-inductive vector control can control the slip of the motor.
(3) During the operation of the wire drawing machine, the load characteristics of the motor and the generator often occur, and when the load is the motor characteristic, the slip of the motor is positive and changes with the change of the load; conversely, when the load is the generator characteristic At this time, the slip of the motor is negative, and it is easy to exceed the synchronous speed. The negative plant is proportional to the characteristic of the generator, so it cannot be controlled by high-precision proportional linkage.
3. The characteristics of the application of the frequency converter on the wire drawing machine
Inverter products are suitable for use in wire drawing machines. When multiple units are used in proportional linkage, they can be controlled by a common DC bus, and the power saving effect is better. Its main features are as follows:
(1) Using non-inductive vector control technology, it has the characteristics of low speed and high torque, and the characteristic of 0.5HZ up to 150% torque output.
(2) The mechanical ratio design with overspeed operation can improve the starting torque characteristics by 1.5 times.
(3) The proportional linkage of multiple units can be successfully designed to use the DC bus, without adding a braking device, and can be stopped quickly.
(4) The speed accuracy is high, and it has the function of slip compensation.
The following takes the transformation of the wire drawing machine of a certain cable company as an example to introduce the characteristics and usage of the inverter:
When drawing ferrous and non-ferrous metals, each capstan rotates at a different speed, precise synchronous speed control prevents breakage, and high-speed system linkage ensures precise control and maximum system work.
1) Device overview
Wire material: copper wire for cable
Wire diameter: 5mm before stretching, 1mm after stretching
Line speed: 50Hz operation, 703m/min
Coiling spool: inner diameter 300mm, outer diameter 400mm
2) Inverter
Control mode – proportional linkage
Braking resistor——None (using shared DC bus)
Control Accuracy—With frequency converter, regardless of whether the motor is a generator or the characteristics of the motor, the slip will remain unchanged (with automatic parameter identification and slip automatic compensation functions), so high-precision proportional linkage can be obtained.
Wire drawing machine is an important equipment in metal wire processing, which belongs to impact load. Its production quality and efficiency are very important for enterprises. There are three types of wire drawing machines: air pulley, looper and linear. With the development of production technology, AC frequency conversion technology and PLC program control in electrical control have gradually replaced DC motors and torque motors, and established a dominant position.
1. The requirements of the wire drawing machine for the frequency converter
(1) The starting torque of up to 150% is required when the frequency converter is 0.5HZ.
(2) It is required to be able to realize the proportional intermodal control of multiple units, and to automatically adjust the output frequency to keep the speed constant as the load and voltage change.
(3) There must be RS485 communication function and PLC and PC to realize communication control.
(4) It is controlled by common DC bus, and the power saving effect is good.
2. Disadvantages of the traditional V/F control or space vector control inverter
(1) The traditional V/F inverter has low frequency and insufficient torque.
(2) When the load and voltage fluctuate, the speed will be unstable, so high-precision proportional linkage control cannot be achieved. Only non-inductive vector control can control the slip of the motor.
(3) During the operation of the wire drawing machine, the load characteristics of the motor and the generator often occur, and when the load is the motor characteristic, the slip of the motor is positive and changes with the change of the load; conversely, when the load is the generator characteristic At this time, the slip of the motor is negative, and it is easy to exceed the synchronous speed. The negative plant is proportional to the characteristic of the generator, so it cannot be controlled by high-precision proportional linkage.
3. The characteristics of the application of the frequency converter on the wire drawing machine
Inverter products are suitable for use in wire drawing machines. When multiple units are used in proportional linkage, they can be controlled by a common DC bus, and the power saving effect is better. Its main features are as follows:
(1) Using non-inductive vector control technology, it has the characteristics of low speed and high torque, and the characteristic of 0.5HZ up to 150% torque output.
(2) The mechanical ratio design with overspeed operation can improve the starting torque characteristics by 1.5 times.
(3) The proportional linkage of multiple units can be successfully designed to use the DC bus, without adding a braking device, and can be stopped quickly.
(4) The speed accuracy is high, and it has the function of slip compensation.
The following takes the transformation of the wire drawing machine of a certain cable company as an example to introduce the characteristics and usage of the inverter:
When drawing ferrous and non-ferrous metals, each capstan rotates at a different speed, precise synchronous speed control prevents breakage, and high-speed system linkage ensures precise control and maximum system work.
1) Device overview
Wire material: copper wire for cable
Wire diameter: 5mm before stretching, 1mm after stretching
Line speed: 50Hz operation, 703m/min
Coiling spool: inner diameter 300mm, outer diameter 400mm
2) Inverter
Control mode – proportional linkage
Braking resistor——None (using shared DC bus)
Control Accuracy—With frequency converter, regardless of whether the motor is a generator or the characteristics of the motor, the slip will remain unchanged (with automatic parameter identification and slip automatic compensation functions), so high-precision proportional linkage can be obtained.
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