Enamelled Wire is a Copper Wire coated with a very thin layer of insulation. It is used in the construction of transformers, inductors, motors, speakers, and other applications which require tight coils of wire.
A transformer is a device that transfers electrical energy from one circuit to another through its coils (windings). The properties needed for motor windings are similar to those needed for transformers, but with the additional requirement to withstand mechanical vibration and centrifugal forces at operating temperatures.
The wire itself is most often fully annealed, electrolytically refined copper. Copper Enamelled Wires are often used to improve energy efficiency in electric motors.
Thicker Enamelled Wire is often square or rectangular (with rounded corners) to provide more current flow per coil length.
The most suitable materials for Enamelled wire applications are unalloyed pure metals, particularly copper and aluminium. Copper is considered the best choice conductor for Enamelled wire in terms of chemical, physical & mechanical properties required.
Most often, Enamelled wire is composed of fully annealed, electrolytically refined copper to allow closer winding when making electromagnetic coils. The wire is coated with a range of polymeric insulations, including varnish, rather than the thicker plastic or other types of insulation commonly used on electrical wire. Polyimide insulated magnet wire is capable of operation at up to 250 °C.
Self-supporting coils are wound with wire coated with at least two layers, the outermost being a thermoplastic that bonds the turns together when heated.
Other types of insulation such as fiberglass yarn with varnish, aramid paper, kraft paper, mica, and polyester film are also widely used across the world for various applications like transformers and reactors.
Enamelled Wire are classified by diameter (AWG number, SWG or millimeters) or area (square millimeters), temperature class, and insulation class.
Breakdown voltage depends on the thickness of the covering, which can be of 3 types: Grade 1, Grade 2 and Grade 3. Higher grades have thicker insulation and thus higher breakdown voltages.
The temperature class indicates the temperature of the wire at which it has a 20,000-hour service life. At lower temperatures, the service life of the wire is longer (about a factor of 2 for every 10 °C lower temperature). Common temperature classes are 105 °C, 130 °C, 155 °C, 180 °C and 220 °C.
Enamelled Wire can work continuously for 155 °C and 180 °C environment with good welding resistance & high performance.