An electromagnet is a type of magnet composed of a battery and iron wire that uses electric current to generate a magnetic field. The magnetic field is generated when the electric current passes through a wire, and the field dissipates when the current stops. The primary function of electromagnets is to lift metallic objects as well as being utilized in the design of many different machines and electronic systems.
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Applications of Electromagnets
An electromagnet differs from any other magnet because its magnetic field is created from the flow of electrical current. In order for the magnet to work properly, the current must be turned on. When turned off, the magnetic field will diminish. These magnets are used in various applications, including automotives, junk yards, electronics, circuit breakers, and many more. Scientific laboratories, manufacturing plants that handle scrap metal, the automotive industry, and appliance and electronic manufacturers all benefit from the use of electromagnets. In addition, they are part of the design of electric motors, generators, doorbells, circuit breakers, TVs, speakers, and read and write heads for hard disks and tape drives. In the automotive industry, electromagnets are used to manufacture brakes and clutches in vehicles. In factories and plants, electromagnets are used to lift and suspend scrap metal and other heavy metallic objects like billets, steel plates, bars, and forgings. In many of these applications, a permanent magnet can be used instead of an electromagnet; however, electromagnets offer the advantage of being able to manipulate the magnetic field over a wide range at a rapid pace.
There are a couple main components that are utilized in the formation of electromagnets: a battery and an iron wire. This wire is often formed into a coil and can be formed into various shapes, including that of a helix, making it a solenoid coil, and that of a donut-shape, making it a toroid coil. In addition, the material of iron is used as the wire component in electromagnets because it belongs to a small group of metals that exhibit ferromagnetic properties and generates a magnetic field when exposed to an electrical current. The magnetism only exists when current is flowing from the battery. This type of soft iron core is also referred to as a ferromagnetic core and offers extremely high magnetic permeability.
How Electromagnets Work
A simple electromagnet can be easily made by wrapping some insulated copper wire around an iron foundation and attaching a battery to the wire to create the electric current. When the wire is connected to the battery, the iron will become magnetized. When disconnected, it will lose its magnetism. This is an easy example of how electromagnets work, but every electromagnet works the same way no matter how big or small the scale of the magnet is. These magnets are often used in junk yards that receive old cars that need to be crushed. Most of the cars do not work anymore, and they cannot be driven to be moved. In order to move them, a crane is used with an electromagnetic head. The circuit is turned off until the crane head is hovering over the car it wants to pick up. When the electric current is turned on, the car immediately attaches to the head of the crane through magnetic force. While attached, the crane moves the car to where it needs to go, and the electric current is turned off to release it to its destination. These magnets are very convenient because the magnetic field can be controlled. The only downside is that electric energy is needed to create the magnetic field.
Types of Electromagnets
There are two main types of electromagnets: flat-fraud and parallel-pole. Flat-fraud is mainly used when the magnet is able to attach itself to a smooth, flat piece of metal. Parallel-pole electromagnets have two poles spaced far apart from each other that allow the magnetic field to have a greater reach. These are used when the metallic object is of an irregular shape and only comes in partial contact with the magnet surface.