Development and Experience of U.P.S. Systems During the 1970´s

The year 1980 marks the end of a decade, which has seen the development of Uninterruptible Power Systems (U.P.S.) from a laboratory design to a commodity item. This presentation looks back at the major circuits which have been employed, and gives reasons why some have not survived. Failure statistics are given for a recent design to illustrate the state of the art.