Earticle

<P>In this study, in order to analyze the lifetime for flexible cables used in portable electric machines, artificial accelerating aging was carried out for VCT(Vinyl Cab-Tire) cables in consideration of thermal, mechanical and electrical multiple-stresses. Accelerated aging factors were calculated with aging temperatures based on the Arrhenius relationship. Through Weibull statistical analysis in the AC breakdown voltages for aged cables after low-temperature mechanical tests, it was analyzed that AC breakdown voltages were proportional to the elongation rates and 19kV of the scale parameter in Weibull analysis was suggested as limit value of lifetime. Using this criterion, it was deduced that the lifetimes with thermal and mechanical multiple-stresses for 70 degrees C, 50 degrees C and 40 degrees C continuous operation were calculated to be 3.3 years, 9.9 years and 15.7 years respectively. Based on these analysis procedure, it is possible to suggest the lifetime assessment technique with multiple stresses for low voltage cables.</P>