Power Sag/Surge Testing for Equipment Reliability Improvement

The need for testing military and non-military subsystems for their ability to tolerate inevitable transient variations in the electrical bus voltage powering them is established. Various military and non-military standards defining AC and DC powerline sag and surge limits for durations greater than 1 millisecond are compared. Arguments are put forth for simulating such transient conditions in the EMC Test Laboratory, both during equipment development tests and as part of the equipment production qualification tests. Laboratory production of powerline sag and surge conditions is discussed, with a detailed compar­ ison of off-line power amplifiers and on-line thyristor controllers test equipments being made.