light industry

First, summary
This paper introduces the Oerlikon drive speed sensorless vector inverter alternative torque motor in plastic machinery and printing machinery are rolling device applications, because it has a wide speed / torque setting range, operating characteristics, smoother has more and more is used to plastic packaging and printing enterprises.
(1) an overview of torque motor
Torque motor is a kind of special motor with soft mechanical properties and wide speed regulation range. Torque motor include: DC torque motor, AC torque motor, and brushless DC torque motor.
(2) the construction principle of torque motor
When the load is increased, the speed of the motor can be reduced automatically, and the output torque is increased, and the load balance is maintained. Torque motor blocking torque is high, blocking the current is small, can withstand a certain period of time to stop running. Because of the high resistance of the rotor, the loss is large, the heat generated, especially in low speed and stall more serious. Therefore, the motor on the back end cover with separate axial or centrifugal fan (small output torque 100 frame size and all the following except), for forced air cooling, torque motor with controllable silicon control device, voltage and speed regulation, speed range of up to 1:4, the speed change rate is less than or equal to 10%. This series motor features make it suitable for winding, uncoiling, plugging rotor and speed occasions and other purposes, is widely used in textile, wire and cable, metal processing, paper making, rubber, plastic, printing machinery and other industrial fields.
(3) the main characteristics of torque motor
The characteristics of the torque motor is with soft mechanical property and can be locked rotor. When the load torque increases to automatically reduce speed and increase torque output. When the load torque is certain value change the terminal voltage of the motor can drive. But the speed of adjustment rate is not good. So the motor shaft and a speed measuring device, with controller. The speed measuring device output voltage and the controller given voltage is compared, to automatically adjust the terminal voltage of the motor. The motor stable!
With low speed, large torque, strong overload capacity, fast response, good linearity, small torque ripple and so on, can directly drive the load eliminating the reduction of transmission gear, thus improving the system's operational accuracy. For different performance indexes, the motor air gap, air gap, air gap of three different structure, air gap structure, can meet the requirements of the general use of precision, has the advantages of low cost; the air gap structure, because the air gap increases, eliminates cogging effect, reduce the torque fluctuation, the nonlinear change of reluctance remove the motor better linearity, electromagnetic air gap increased, armature inductance is small, small electrical time constant, but the manufacturing cost is high; the air gap structure, its performance is slightly lower than the air gap structure of motor, but much higher than the air gap structure of motor, and the volume is smaller than the air gap structure of motor, manufacturing cost is lower than the air gap structure of motor.
(4) torque motor applications
In machinery manufacturing, textile, paper, rubber, plastics, metal wire and wire and cable industries, the need to be wrapped in the roll (disk). Winding diameter from the beginning to the end is the larger the volume, in order to keep the volume of the material is uniform (that is, the line speed constant), it requires the winding speed, the smaller the volume, the larger the winding force. Application of winding, unwinding (braking characteristic of constant power stepless speed regulation, etc.).
1, winding
Winding is a very important process in the processing of wire and cable, textile, metal processing, paper making and so on. Product winding reel diameter increases gradually, in the whole process of maintain is rolled products tension constant is very important, because the tension over the General Assembly will wire diameter attenuated or even pull off, or cause the thickness of the product is not uniform, and the tension is too small can result in loose winding. In order to maintain constant tension in winding process, must reel disc size increases driving reel motor output torque also increases onto the coiling in the products, and the line speed of the winding products remain unchanged, shall be so reel speed decreases, the mechanical characteristics of the torque motor can just meet this requirement.
2, open book (brake characteristic of constant power)
Open book or loose winding, unwinding, line etc.. In industrial production, the product is sometimes transported to the next process. In the process of conveying, opposite to the direction of product a and the transmission of tension, and with cylinder diameter changes, while keeping the drive product line speed and reverse tension constant. This requires that the motor with braking characteristic of constant power.
3, stepless speed regulation
The mechanical characteristics of the torque motor can be realized under the control of the modern servo drive device for high stiffness, so it can be used in place of the original mechanical drive device to realize the direct drive. At present, there is a CNC rotary table with torque motor as the core component and a CNC swing angle milling head. When these products in bulk power ratio is still not as good as the mechanical transmission device, but because it has no transmission clearance, no wear, high transmission accuracy and efficiency advantage, has begun to in precision equipment to promote the use of the line.
4, blocking
In some special occasions, sometimes at the request of the motor in a period of time, keep still for a moment, such as cable volume initialization stage should keep a tight; large forging press forging clip holding device. Due to the larger impedance of the torque motor, the blockage of the current is smaller, and the forced ventilation is adopted, so that the blockage and the request can be satisfied in a certain time. Allow block transfer time should be according to the nameplate on the calibration value, for long the stall time, choose a larger torque motor, by reducing the terminal voltage of the motor torque.