White Paper: Leading Power Factor Loads And Their Impact On UPS Capacity And Performance

By Chuck Heller

Server technology has rapidly advanced in response to market needs, delivering high-density, highly reliable computing without the massive harmonics issues inherent with older power supplies. One unintended consequence of this advance is a shift in load power factor characteristics in data centers from a range of 0.6-0.9 lagging to a range of 0.9 leading to 0.9 lagging. UPS's of older designs cannot deliver their full rated power to these new loads and must be de-rated or retrofitted. Therefore, data center designers and operators must be vigilant in order to avoid problems including insufficient capacity, nuisance alarms, and even downtime due to overloads. Fortunately, new UPS designs can avoid these issues while delivering more real power available to the load.