Simply put, electromagnets create a magnetic field when an electrical charge is passed through them. Although magnets were known about for centuries, it was not until the early 1800s that it was discovered that electrical currents also generated magnetic fields. In the 1820s, William Sturgeon became the first scientist to demonstrate the way in which these fields could be put to use and the idea of the electromagnet was born. Since his time, electromagnets have been used in anything from small components to large industrial machines. To what uses are electromagnets put today?
Something that is now found in nearly every advanced hospital around the world, MRI machines are used for a wide range of diagnostic purposes. What many people fail to realise is that the principle of electromagnetics is crucial to their function. In fact, many use a combination of electromagnets and radio waves to be able to scan human bodies.
Magnetic Separation Systems
One of the many industrial uses of electromagnets is in the field of separation. You will often see a large electromagnet being used in scrap metal yards to lift and place ferrous metals away from non-ferrous ones, for example. Once power to the electromagnet is cut, items can be dropped. When it is turned on, they are picked up. This sort of system is also widely used to separate metals like tin and aluminium from steel and iron at recycling centres.
Solenoid Fuel-Injection Systems
A fuel-injection system is used in many kinds of motorised transport these days, notably diesel-powered cars. Essentially, a fuel injector works because a solenoid—a type of electromagnetic device—delivers more fuel to a car's cylinder at just the time it is needed by powering up the electrical field as the car is moving. Custom-built solenoids are also used in things like pinball machines and dot matrix printers using a similar method.
Many forms of rotary electric motors employ electromagnetics. Typically, a magnetic field will be turned on and off, which makes a spindle move to a new position each time. The spindle can then be used to power anything that requires a rotary force, such as a camshaft, for example.
Some public transportation systems rely on big electromagnets to lift trains up above their tracks and to, therefore, move them without rolling resistance caused by wheels. Maglev (magnetically levitated) trains are not mainstream, but they are becoming increasingly viable in commercial terms.Share