Ryousuke Obika, Tadashi Ishii, Yoshinori Tatematsu and Katsumi Osada
In recent years there is a trend for electrical equipment and industrial motors to be inverter controlled, as energy saving is promoted together with the downsizing and performance improvement of these equipment. While it has been suggested that excessive surges accompanied by inverter control adversely affect motor insulation systems, this does not make an exception for magnet wire. Thus magnet wires are required to have better resistance against inverter surges than before, because, when the wires are exposed to such voltages, degradation of the insulation layer is caused by corona discharge, unless sufficient insulation and creepage distance are provided between the wires. With respect to driving motors for electric vehicle (EV) and electric hybrid vehicle (EHV) also, similar phenomena are observable depending on the design of motors, thereby leading to a burgeoning demand for a magnet wire that is well adapted for inverter-controlled equipment.
To satisfy these demands, the authors have recently developed a new magnet wire with superior inverter surge resistance. Characteristics of this wire will be described in this report, whereby the life under high-frequency voltage has been improved significantly.