The influence of temperature on the efficiency of magnet wire insulation

Efficiency is defined as the ratio of output to input energy. Design engineers strive for maximum efficiency or an efficiency as close to unity as is practical. Maximum efficiency with respect to magnet wire insulation requires that the ratio of output to input energy approach zero. For maximum efficiency, magnet wire insulations have to exhibit minimum Ioss while maintaining physical strength under voltage stress and are required to do so at their operating temperature. The work outlined compares the effect of temperature on dissipation factor, dielectric constant, dielectric strength, and insulation resistance of a wide variety of magnet wire insulations used in the industry. The results indicate that while some magnet wire insulations have a higher temperature rating, they should not be arbitrarily substituted because of their low efficiency. This is especially true where magnet wire insulations are subjected to higher than normal turn-to-turn voltage.