The principle of magnetic cranes helps
There is a magnetic field in the magnet. When the metal is adsorbed it will also be magnetized and magnetic and magnetic field, and its magnetic field lines are in the same direction as permanent magnets. According to this principle, we can move another magnet near it, and make their magnetic field go in the opposite direction of repulsion, thus leaving the metal out.
Generally it is electromagnetism, the electricity that produces magnetic feeling, can absorb the things like iron, cut off the power, the magnetism disappears, put down the thing
I made a crane, never heard of a permanent magnet crane, we do all electromagnet!! Did you add it yourself, didn't the manufacturer give the original?
