What are the main characteristics of electromagnetic crane?

According to the understanding of the application of electromagnetic gun, the main component of electromagnetic crane is electromagnet, and its working principle is the principle that magnetism is produced by power-on and disappeared by power-off. So the answer is: electromagnet; The magnetism is generated by the current, and the magnetism disappears by the current. The basic property of electromagnet is that when the current is connected, it will produce magnetic force, and when the current is disconnected, the magnetic force will disappear. But also can control that magnitude of the magnetic field and the direction of the magnetic pole. Therefore, electromagnets are widely used, such as electromagnetic cranes, electric bells, electromagnetic relays, maglev trains and so on.