Problem with Electromagnets at E.O.T Cranes.

I have checked each and everything at panel, CRD upto the Electromagnets, it is a circular magnets used for filling Transfer Car Trolley with Scrap at Steel Melt Shop, but i have noticed one thing, when i magnetize the magnet it magnetized but when i drop the magnet the DC Contact or of the magnet produces a huge flash with fire. it is also taking 120 Amp instead of 100 amp, the variate along diode also burns out while dropping the scrap means demagnetizing the electromagnet, which circuit i must have to check for this condition.