This document discusses APFC (Active Power Factor Correction) and how it relates to UPS systems. It explains that APFC improves energy efficiency but requires more energy during startup. Traditional UPSs cannot handle the startup surge and would indicate overload. However, the APFC Office UPS series uses patented PWM control to extend pulse widths and provide more startup energy without affecting frequency, allowing it to properly power loads with APFC without overloading. The APFC Office UPS thus eliminates the need for oversized UPSs just to accommodate APFC startup demands, saving cost and space.