Dielectric integrity of magnet wire insulations under multi-stresses

With the increased use of PWM-type adjustable speed drives in the motor industry, the incidence of premature failure in the wire insulation has been increasing. Investigation of the failure mechanism of wire insulations used in inverter-driven motors is therefore of interest and necessary. The failure behavior of insulation under fast rise time pulse voltage with very high frequency has rarely been studied until recently. Being aware of the limited research conducted in this field, the authors´ goal is to design a testing system that is able to vary the parameters which characterize power inverters (voltage, frequency, rise time, duty cycle, etc.). By understanding the failure mechanism under such conditions, new insulation can be developed for this environment. In the work presented here, not only the relation between the failure and these parameters is discussed but also dielectric performance of different wire insulations (both conventional wires and a novel wire) is evaluated