Centrifuge screw overspeed issue
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Recently, our factory’s centrifuges have been experiencing shutdown issues. Under normal operation, the drum rotates at 1800 revolutions per minute, with a differential speed of 50 revolutions per minute. Before a shutdown occurs, the differential speed gradually drops to zero, after which an alarm is triggered indicating that the screw motor is running too fast; this leads to the machine stopping. Replacing the frequency converter did not resolve the problem. It was later discovered that the fuse on the DC bus had blown; upon inspection, the fuse was found to be damaged. After replacing it, the machine started operating normally again. I’d like to ask the experts here at the station: what is the control logic of this frequency converter? Why does the spiral motor run at excessive speed after a fault in the DC bus fuse?
Is the power supply controlled to use direct current?
Does the drum have external kinetic energy? The phenomenon seems to be caused by external kinetic energy, which leads to the drum spinning too fast and sending power back to the inverter’s DC bus
The drum and the screw each have their own drive motor; the overload alarm on the frequency converter is for the screw drive motor.