An electromagnetic lifter includes at least two polar expansions shaped for transporting a horizontal axis coil of hot-rolled steel. The polar expansions are connected through a ferromagnetic circuit and respective cores around which solenoids are arranged. A detection coil is arranged around each of the cores suitable to detect the change in the flux linked to the coil, and a control unit connected to the detection coils compares the values detected by each of them in order to authorize or not the transport. The relevant operating method includes a first check that the difference between the values detected by the two detection coils is below a preset threshold, and in the affirmative a second check that the overall decrease in the linked flux is below a second preset threshold, the issuance of an authorization signal to the transport being possible only in case of positive outcome of both checks.