Bag the sags

This article describes the vulnerability of variable speed drives (VSD) to voltage sags on a theoretical basis. Then, three embedded mitigation methods are addressed in theory which protect textile processes against voltage sags, and practical measurements with a sag generator are shown. The use of embedded solutions such as kinetic buffering and boost convertor or an active front end will increase the voltage sag immunity of the process. Finally, two processes in the textile industry are described, and a brief cost-benefit analysis of the solutions is made. Experiments with a sag generator show that the voltage sag behaviour can be well described by theoretical models.