electromagnet
A device with an iron core inside that uses a coil of electric current to make it magnetic like a magnet is called an electromagnet and is usually made in the shape of a bar or shoe. The core should be made of soft iron or silicon steel with simple magnetization and simple disappearance of magnetism. Such an electromagnet is magnetic when it is powered on, and then disappears after the power is cut off. Electromagnets have many benefits: the presence or absence of electromagnet magnetism can be controlled with on and off currents. The size of magnetism can be controlled by the strength of the current or the number of turns of the coil. Electromagnets are widely used in daily life. Electromagnet is an application of current magnetic effect (electrogenerated magnetic), closely connected with the day, such as electromagnetic relay, electromagnetic crane, maglev train and so on.
The invention of the electromagnet
In 1822, French physicists Arago and Gay-Lussac discovered that when an electric current passes through a wound wire with an iron in it, it magnetizes the iron in it. This was actually the beginning of the discovery of the electromagnet principle. In 1823, Sturgeon made a similar experiment: he wound 18 turns of bare copper wire around a U-shaped iron bar, which was not a magnet. When the copper wire was connected to a volt battery, the copper coil around the U-shaped iron bar was densely covered with magnetic fields, which turned the U-shaped iron bar into an electromagnet. The magnetic energy of this electromagnet is more than the permanent magnet can be put many times larger, it can suck up the iron 20 times heavier than it, and when the power cut off, the U-shaped iron bar will not suck up any iron, from the beginning to become a general iron bar.
Sturgeon's invention of the electromagnet made people see the bright future of converting electrical energy into magnetic energy, which was soon spread in Britain, the United States and some coastal countries in Western Europe.
In 1829, the American electroscientist Henry Sturgeon electromagnet equipment made some modifications, insulation wire instead of bare copper wire, so there is no need to worry about the copper wire too close and short circuit. Because the wires have an insulating layer, they can be tightly wound round and round, and the more densely packed the coils are, the stronger the magnetic field will be, thus greatly improving the ability to convert electrical energy into magnetic energy. By 1831, Henry had produced a newer electromagnet that, although not very large, could lift a ton of iron.
The invention of the electromagnet also greatly improved the power of the generator.
Electromagnet introduction: Electromagnet can be divided into DC electromagnet and AC electromagnet two types. If in accordance with the use of electromagnet to distinguish, the first can share out the following five :(1) traction electromagnet - mainly used to traction mechanical equipment, open or close a variety of valves, in order to perform the mission of automatic control. (2) Lifting electromagnet - used as lifting equipment to lift steel ingot, steel, iron sand and other ferromagnetic data. (3) Brake electromagnet -- mainly used for braking the motor to achieve the purpose of accurate parking. (4) The electromagnetic system of automatic electrical appliances -- such as the electromagnetic system of electromagnetic relay and contactor, the electromagnetic trip of automatic switch and the operating electromagnet, etc. (5) electromagnets for other uses, such as the electromagnetic chuck of the grinder and the electromagnetic vibrator, etc.
