(1) In a conventional screw extruder system, the screw is driven by a DC motor. In the case of direct drive, the screw is driven directly by the gearbox; in the case of indirect transmission, the screw is driven by the belt and the traction disk. The traditional DC motor itself has certain disadvantages: for example, the brush of the DC motor is replaced once a month. In a dusty or corrosive environment, the DC motor needs to be cleaned frequently, and sometimes it needs to be DC motor from the outside of the workshop. Into the clean cooling air.
(2) The disadvantage of the indirect drive screw extruder is that there is a belt slip, the belt will cause a certain energy loss, and more mechanical devices increase the possibility of wear and failure. The biggest drawback of DC motor is excessive noise, brush ignition, rotor pollution, motor temperature is too high, exhaust is insufficient and motor vibration. Therefore, the screw extruder using a DC motor has higher maintenance costs, and the initial cost of the DC motor is also higher.
Fourth, the realization of frequency conversion transformation.
SAJ-8000 series inverters are used in extrusion equipment and have high-quality operation characteristics, which is determined by the good product performance that the vector-controlled inverter itself can provide.
1High-performance CPU provides higher frequency response The high-speed CPU built into the SAJ-8000 series inverters has high control accuracy and fast response frequency performance. The process requirements of the extruder are mainly to control the constant pressure of the outlet. When the equipment starts to work, the speed is controlled. When the demand pressure is reached, it is switched to pressure control. The switching process should have no impact and require high control accuracy of the inverter to respond to the pressure signal.