1 constant tension control principle
The essence of constant tension control for unwinding and rewinding process is the need to know the load coil diameter changes in operation, because the roll diameter changes, resulting in order to maintain the load operation, split machine need to output torque of the motor to follow the roll diameter change. For V series inverter, due to be able to do so can complete the torque control, constant tension coiling control. V series frequency converter provides three analog input port, AUI, AVI, ACI. The three analog input can be defined as a variety of functions, therefore, can choose a road as a torque setpoint, another road as the speed limit. 0~10v corresponds to the inverter output 0~ motor rated torque, so that through the adjustment of voltage 0~10v can finish the constant tension control. Du Yu slitting machine, coil diameter calculation of the part is calculated by the tension controller, of course, use the PLC architecture to realize there is no problem. That is to say, can set up tension in the man-machine or text, through the calculation of PLC roll diameter, T=F*D/2, so we can figure out the size required torque motor output torque, given by the analog output to the V series inverter terminal can be.
Calculation of 2 synchronous speed
Since we know the inverter working at low frequencies, the characteristic points of the machine of AC asynchronous motor is not good, the activation of torque at low and linear, so try to avoid rolling motor operating below 2HZ in the whole process of rolling. Therefore, the winding motor has a minimum speed limit. For the four stage motor. The synchronous speed is calculated as follows: n1=30f1/p=n1=1500r/min=2HZ/50HZ=N/1500=N=60rpm/min
(F1 is the rated frequency, P as the pole number, N1 for the synchronous speed)
3 speed operation
When the maximum roll diameter, can calculate the winding operation of the whole process of the low speed:
V= - *D*n/i=Vmin=3.14*1.2*60/9=25.12m/min
Tension control, strip confidential limit of speed, otherwise there will be a roller coaster, so the speed limit operation.
4 tension and torque calculation
If F*D/2=T/i (F-- tension, D-- coil diameter, T-- torque, i-- reduction ratio), =F=2*T*i/D for AC motor of 3.7KW, the rated torque is calculated as follows: T=9550*P/n=T=24.88N.m so Fmax=2*24.88*9/0.6=74.64N (the rated torque Rated power of T-- motor, P-- motor, n== motor rated speed)