The discussion of centrifuge start-up is always a complicated problem. Now most of the new horizontal screw centrifuge manufacturers have chosen the method of variable frequency starting. In order to avoid overload maintenance action of the frequency converter, the starting time is usually set for a long time, so that it takes a long time for all four normal starting putting into operation, the working efficiency is very low. In addition, most of the manufacturers of horizontal screw centrifuges choose the one-to-one corresponding starting method of frequency converter centrifugal head, the operation is also relatively cumbersome.
In order to shorten the starting time, the step-by-step starting method can be selected: set the initial working frequency as low as 20Hz, enter the normal working frequency after the current is normal, for example, 50Hz. The next centrifugal roller can be started only when the working current of the previous centrifugal roller is within its rated value. Many frequency converters have multi-stage speed control function. This step-by-step starting method can greatly shorten the starting time improve the working efficiency.
On this basis, a small PLC controller can be added to control the working frequency switching of each frequency converter by using the internal time relay of PLC. Of course, it can also add time relay according to the actual operation needs to directly correct the time required for starting.
According to the above method, it is only necessary to confirm the starting time of each bag pulling centrifuge during the device commissioning, set the relevant sequence in PLC directly set the frequency switching time on the additional time relay, use a button switch to input the starting command in the work, so that the starting the heart can be completed actively in a short time.
The PLC points used are few the price is high, but it simplifies many operation methods time in the actual work, so it should get more obvious preparation. Furthermore, it will make the structure of productive forces more reasonable, the layout more scientific the efficiency higher.