SANCH VFD (Variable-frequency Drive) application on sanding machines

1. Summary:

The VFD (Variable-frequency Drive) control system has high operating speed and stable tension requirements, and can control the AC motor very well.

2. Characteristics of sanding machine:

Sanding machine is an important process in the printing and dyeing process for post-processing dyed fabrics to increase their added value. The traditional driving method is to use a DC motor to drive, using a ceramic plate resistor linked to the lifting rod to obtain the feedback signal, and adjust the excitation current of the DC motor to achieve the purpose of speed regulation synchronization. Due to the complex structure of DC motors, the price is relatively expensive, and there are commutators and brushes. During the application process, the failure rate is high and the maintenance volume is large. Especially in the printing and dyeing industry, the equipment is exposed to alkaline and high humidity air environments for a long time. In the process, its structural shortcomings are quickly exposed, sometimes seriously affecting production. With the extensive use of variable frequency speed regulators in this industry, their synchronous speed regulation features such as high precision, high reliability, and simple peripheral system structures have gradually been recognized and accepted by people. The following is our review of Jinjiang XX Machinery Factory The sanding machine provides a VFD (Variable-frequency Drive) control solution.

3. Control chart

4. Control instructions:

1. The sanding machine is divided into two parts: the sanding area and the traction area. The control of the sanding area is relatively simple. According to the customer's needs, we set the speed on the touch screen and use the D/A module to convert it into an analog quantity drive VFD (Variable -frequency Drive) to adjust the motor speed online, and can freely select forward and reverse rotation.

2. Below we will give a detailed explanation of the tension part of synchronous control. The entire traction mechanism is composed of 7 motors. Mechanically, gear reduction has been used to adjust the linear speed of the 7 motors to basic synchronization. In order to make our VFD (Variable- frequency Drive) to control the tension more accurately. There is a cylinder in front of each motor of the water rolling motor, drying 1, drying 2, and drying 3, and a resistive displacement sensor is mechanically transmitted. The tightness of the cylinder can be strictly controlled. We use the difference in A/D value output by the sensor to control the VFD (Variable-frequency Drive) through the tightness of the cylinder so that the tension can be replenished in time.

3. We handle the tension part like this. We write the data program of the entire system through floating point numbers, and the data processing is relatively accurate. We first select the 5V voltage value from 0V-10V as the intermediate output value, divide the current speed of the motor by the voltage value of 5V, and get the speed of our motor at each volt. We set each sensor through the touch screen. The voltage value at the middle position also sets the speed increase rate for each VFD (Variable-frequency Drive) through the touch screen. We use the real-time value sent by the displacement sensor minus the intermediate voltage value of our set value. The data at this time is the tension value converted into the difference in voltage. This data is then multiplied by the speed per volt. This data is the speed value of the motor that we convert through tension. We multiply the final speed value by our amplitude, which is the value we finally lose to our VFD (Variable-frequency Drive). , so that the VFD (Variable-frequency Drive) runs smoothly, quickly replenishes within the range of the difference, and maintains constant speed and constant tension.

4. Because the seven traction motors have achieved a relatively constant linear speed mechanically, we made real-time online adjustments to the cloth incoming and outgoing traction, as well as the cloth dropping motor.

5. In terms of overall speed adjustment, we set the starting speed and control buttons for gradual acceleration, which can be adjusted through the touch screen and external buttons.

5. Conclusion:

The successful application of SANCH VFD (Variable-frequency Drive) on the sanding machine has brought the control of the sanding machine to a new level, achieving constant tension and constant speed control. In the three months since the trial operation, , both the operation of the VFD (Variable-frequency Drive) and the control function of the system have been well received by customers!