Magnet wire or enameled wire is a copper wire or alumin […]
Magnet wire or enameled wire is a copper wire or aluminum wire covered with a very thin insulating layer. It is used to build transformers, inductors, motors, generators, speakers, hard disk head actuators, electromagnets, electric guitar pickups, and other applications that require tightly insulated wire coils.
The wire itself is usually fully annealed, electrolytically refined copper. Aluminum enameled wire is sometimes used in large transformers and motors. As the name implies, insulating materials are usually made of tough polymer film materials, rather than made of enamel.
Aluminum magnet wires usually use one to four build-thick polymer film insulation layers, usually with two different compositions, to provide a tough, continuous insulation layer. The insulation of thicker square or rectangular enameled wires is usually reinforced by wrapping with high-temperature polyimide or glass fiber tape, and the completed windings are usually vacuum impregnated with insulating varnish to improve the insulation strength and long-term reliability of the windings.
Aluminum enameled wire is sometimes used as a substitute for large transformers and motors, mainly for economic reasons. Due to its lower conductivity, aluminum wire requires 1.6 times larger cross-sectional area than copper wire to achieve comparable DC resistance.