The Application Of Total Digital Intelligent Control System On Electromagnet Crane

Magnet crane is a kind of electromagnetism lifting equipment. Magnet force is produced to lift weight when current pass through electromagnet loop. As it lifts and unloads steels directly by electromagnet force and it doesn't need to enlace and pothook steels, so it accelerates load and unload speed and gets a very important position in steel production.The problems that current is too large and electricity power is wasted are easy coming forth as the electromagnet loop needs saturation excitation when the traditional electromagnet crane is in practical operation. At the demagnetization stage, the power that deposited in loop is releasing by heating resistor, and doesn't feed back to electricity net. It is also a large waste. At the other hand, electromagnet is a big inductance load, when DC contactor is on or off, electricity arc is easy to happen and burnout the contactor. So the fault rate is very high and it needs much repairing work.Aim at these problems that appear in practical operation, this article proceeds with the magnetism route of electromagnet and analyses and studies on the excitation and demagnetization processes deeply. And an intelligent optimization project has been put forward. In this project the excitation current has been optimized to meet the excitation requirement and make the waste least. At the demagnetization stage, PLC and whole control bridge circuit are used to demagnetize the electromagnet fast. And power deposited in loop can feed back to electricity net. So the electricity power is saved and the problem that equipment is burnout by electricity arc is avoided.