Essentially, an electromagnet consists of a soft iron core and turns, or windings, of electrically conducting wire. Increasing the size of the core, the number of windings and the level of current that flows through the wire can produce a magnet much stronger than any natural magnet.
Even the strongest natural magnet cannot lift a heavy steel object, such as an automobile, but industrial electromagnets can. Another advantage of electromagnets is that the magnetic force can be controlled by switching the current that flows through it on or off.
Huge, strong electromagnets are employed in heavy industrial cranes, such as those in salvage yards, to lift, move and drop heavy iron or steel objects. These electromagnets are typically contained in a heavy cage or machined steel casing, insulated from the copper or aluminum windings inside.
In addition to their lifting capability, electromagnets are also employed in the braking systems of certain types of heavy-duty cranes. These are typically coupled at the rear of the crane motor, together with a fan that ensures air circulation.