Application of the hottest Ourui frequency convert

The application of Ourui inverter in the winding equipment of plastic and printing machinery

I. Abstract

this paper introduces the application scheme of Ourui transmission with speed sensor vector inverter instead of torque motor in the winding equipment of plastic and printing machinery. Because it has a wide speed/torque setting range and smoother operating characteristics, it has been increasingly used in plastic packaging and printing enterprises

(1) overview of torque motor

torque motor is a special motor with soft mechanical characteristics and wide speed regulation range. Torque motors include: DC torque motors, AC torque motors, and brushless DC torque motors

(2) B. regularly check the structural principle of the screw torque motor at the jaw

when the load increases, the speed of the motor can automatically decrease, while the output torque increases, maintaining balance with the load. The torque motor has high locked rotor torque and low locked rotor current, and can withstand locked rotor operation for a certain period of time. Due to the high rotor cathode, large loss and large heat generated, especially in low-speed operation and locked rotor, the motor is equipped with an independent axial flow or centrifugal fan on the rear end cover (except for the output torque of less than 100 frame number and below) for forced ventilation and cooling. The torque motor is equipped with a silicon controlled control device, which can adjust the pressure and speed, and the speed range can reach 1:4, with a speed change rate of 10%. The characteristics of this series of motors make them suitable for winding, uncoiling, locked rotor, speed regulation and other applications. They are widely used in textile, wire and cable, metal processing, papermaking, rubber, plastics, printing machinery and other industrial fields

(3) main characteristics of torque motor

torque motor is characterized by soft mechanical characteristics, which can block rotor When the load torque increases, it can automatically reduce the speed and increase the output torque at the same time When the load torque is a certain value, the speed can be adjusted by changing the motor terminal voltage But the speed adjustment rate is not good! Therefore, a speed measuring device and a controller are added to the motor shaft The terminal voltage of the motor is automatically adjusted by comparing the output voltage of the speed measuring device with the voltage given by the controller Stabilize the motor

it has the characteristics of low speed, large torque, strong overload capacity, fast response, good characteristic linearity and small torque fluctuation. It can directly drive the load without reducing the transmission gear, thus improving the operation accuracy of the system. In order to obtain different performance indicators, the motor has three different structural forms: small air gap, medium air gap and atmospheric gap. The small air gap structure can meet the general accuracy requirements, with the advantage of low cost; The air gap structure eliminates the cogging effect, reduces the torque fluctuation, basically eliminates the nonlinear change of magnetoresistance, and the motor linearity is better. The electromagnetic air gap is increased. The American packless shock hose has small armature inductance and small electrical time constant, but the manufacturing cost is high; The performance index of the medium air gap structure is slightly lower than that of the air gap structure motor, but much higher than that of the small air gap structure motor, while the volume is smaller than that of the air gap structure motor, and the manufacturing cost is lower than that of the air gap structure motor

(4) application of torque motor

in machinery manufacturing, textile, papermaking, rubber, plastic, metal wire, wire and cable industries, products need to be wound on drums (discs). The diameter of the winding is larger from the beginning to the end. In order to keep the tension of the coiled material uniform (that is, the linear speed remains the same), the drum speed is required to be smaller and smaller, and the winding force is required to be larger and larger. Application characteristics winding, uncoiling (braking constant power characteristics), stepless speed regulation, etc

1. Winding

winding is a very important process in wire and cable, textile, metal processing, papermaking and other processing. During product winding, the diameter of the drum gradually increases, and it is very important to keep the tension of the rolled product unchanged throughout the process, because excessive tension will narrow or even break the wire diameter of the wire, or cause uneven thickness of the product, while too small tension can cause winding relaxation. In order to keep the tension constant in the winding process, the output torque of the motor driving the drum must also increase when the diameter of the product wound to the reel increases. At the same time, in order to keep the linear speed of the wound product unchanged, the speed of the reel must be reduced accordingly, and the mechanical characteristics of the torque motor can just meet this requirement

2. Uncoiling (braking constant power characteristic)

uncoiling is also called uncoiling, unwinding, paying off, etc. In industrial production, it is sometimes necessary to transport the products wound on the drum to the next process. In the process of transportation, it is required to apply a force to the product opposite to the transmission direction. Zhang Li Keqiang pointed out in the government work report at the fourth session of the 102nd National People's Congress. At the same time, it is required to keep the linear speed and reverse tension of the product transmission constant with the change of the barrel diameter, which requires the motor to have the characteristic of constant braking power

3. Stepless speed regulation

the mechanical characteristics of torque motor can achieve high stiffness under the control of modern servo drive device, so it can replace the original mechanical drive device to realize direct drive. At present, there are CNC rotary worktables and CNC angular milling heads with torque motors as the core power components. These products are not as good as mechanical transmission devices in volume power ratio, but because they have no transmission clearance, no wear, high transmission accuracy and efficiency, they have begun to be popularized and used in precision equipment

4. Locked rotor

in some special occasions, the motor is sometimes required to maintain a static torque for a period of time, such as tension at the beginning of cable winding; Forging clamping device of large forging press, etc. Because the impedance of torque motor is large; The locked rotor current is small, and forced ventilation is adopted, so it can meet the locked rotor requirements within a certain period of time. The allowable locked rotor time should be based on the calibration value on the nameplate. If a longer locked rotor time is required, a larger torque motor can be selected and obtained by reducing the terminal voltage of the torque motor

5. Other

torque motors can also be flexibly applied according to their various characteristics. For example, they have the characteristics of DC series excited motors, which can be partially used instead of DC motors; Another example is that its rotor has high resistance characteristics and large starting (locked rotor) torque, so it can be applied to the opening and closing of gate (valve) and the driving system with large resistance torque; It can also be used in devices with frequent forward and reverse rotation or various machines with similar actions by taking advantage of its large starting (locked rotor) torque, small starting (locked rotor) current and high mechanical strength of solid rotor

II. Configuration of f3000 instead of torque motor

1 f3000 series frequency converter

2 variable frequency vector motor

3 rotary encoder

III. frequency converter parameter setting and wiring

in the actual working process, the most commonly used is to use only analog quantity adjustment to control the torque, while the speed limit control uses a fixed value, which is not lower than the maximum working frequency required by the equipment

IV. the working process of f3000 frequency converter driving variable frequency vector motor

f3000 frequency converter and variable frequency motor can completely achieve the function of torque motor after replacing torque motor:

1 when the machine is started and unloaded, adjust the torque of the motor by adjusting the torque control potentiometer. Usually, customers will have an experience value, and the speed of the motor will rise to the set speed limit

2 when the winding motor starts with the load, the speed of the winding motor will be reduced due to the load. When the tension of the plastic film from the traction position to the winding shaft reaches the torque adjusted by the motor, the speed will remain unchanged and the winding will continue. If the traction speed is accelerated, the tension of this section of film will be reduced. If it is less than the current torque of the motor, the speed of the frequency converter will be accelerated until it is consistent. Vice versa

3 if the traction motor stops working, the winding motor will also stop due to the excessive tension of the membrane, and the frequency of the frequency converter will be reduced to zero, while maintaining the existing torque so that the membrane will not relax. Once the traction motor starts working, the winding motor will accelerate and decelerate accordingly

v. conclusion

the constant tension reeling function is realized by using the orrui frequency converter instead of the torque but interrelated motor, which has superior torque characteristics, and greatly improves the reliability of the equipment, overcomes the heating condition of the motor, saves electric energy, and reduces the motor failure. Therefore, more and more customers begin to use frequency converter to replace torque motor to realize transverse tension control