What Is Magnet Wire?

If you’ve built an electromagnet, a speaker, a hard disk head actuator or any other device that requires tight coils of insulated wire, odds are it was made from magnet wire. Magnet wire, also known as enameled wire, is a copper or aluminum wire that is coated with a very thin layer of insulation. It is used in transformers, inductors, generators, motors and a long list of electrical components in almost anything that uses electricity.

In fact, a single transformer can power an entire city, and the magnetic fields generated by magnet wire are what turn electrical energy into mechanical or thermal energy in cars, airplanes and many other modern machines.

Magnet wire is sometimes incorrectly referred to as winding wire or enameled lead because of the way it is marketed in hardware stores and hobby shops. In reality, however, magnet wire is copper wire that has been coated with one or more layers of tough polymer film materials. The insulation is not made of real enamel, as some people believe, but it consists of one to four layers of material such as polyester, polyglass or polymide, and is melted onto the copper wire using heat and pressure.

The copper wire used for magnet wire is typically fully annealed to allow for closer turns when making electromagnetic coils. It may be tinned or high-purity oxygen-free copper for higher temperatures or when used in applications such as transformers that are cooled with water or hydrogen gas. Alternatively, aluminium magnet wire is used in large transformers and motors due to its lower cost.

Insulation is very important for magnet wire, as it allows the different turns of the coil to be separated without contacting each other and shorting out. In a coil with hundreds or thousands of turns, the insulation is essential to maintain the integrity of the circuit and the safety of its users.

In addition to electrical properties, magnet wire can be manufactured in a variety of colors and other features. For example, a special type of magnet wire called bondable is designed to have an additional adhesive coating that will bind the turn-to-turn windings into a self-supporting coil. The adhesive is applied either while the wire is being wound, or the coiled wire can be dipped in solvent after it has been wound to activate the bond coat.

While copper magnet wire has been available for more than a century, the rapid rise in demand for electric vehicles and other devices powered by magnet wire is fuelling new innovations in artificial intelligence and robotics, autonomous systems and other cutting-edge technologies. Preformed Litz wire, which is a form of magnet wire, is ideal for these applications because it can be processed into a variety of cross-sectional geometries with minimal damage to individual strands and their insulation. This allows engineers to develop new designs and create revolutionary products that will transform the world.