Influence of voltage sags on personal computers and PWM drives

This paper discusses the sensitivity of personal computers and PWM drives to voltage sags and short interruptions on the basis of extensive test results. The results of the following tests are presented in the paper: testing against various types of single-phase, two-phase and three-phase voltage sags and short interruptions, as well as testing with the ideal and non-ideal supply characteristics. Presented test results show that behavior of both equipment types in the general case cannot be described with only one voltage-tolerance curve. Instead, families of voltage-tolerance curves should be used for description of the PCs and PWM drives sensitivity to voltage sags and short interruptions. Special attention is given to similarities in responses between these two equipment types, what is discussed in detail.