The insulation or overcoating used on rectangular enameled wire is a type of polymer film (varnish) made from a variety of resins—typically polyester, polyglass, or polyamide—to create a tough, continuous layer of protection for the wire and allow for numerous windings in a coil without producing a short circuit. Various types of varnishes produce different characteristics or properties, such as:
High thermal index (AI)
Abrasion resistance (NY)
Self-bonding (SB)
Self-lubricating (SL)
rectangular enameled wire meets temperature classes between 105 °C and 240 °C, providing a guaranteed service life of 20,000 hours at the rated temperature. Magnet wire comes in a variety of sizes and shapes such as rectangular, square, and round. Enameled wire with a thermoplastic layer to bond the coils together is used to create self-supporting coils, which eliminate the need for a bobbin and accommodate tight spaces in various electronics applications.