This is the lowest AC input power draw this specific PSU recorded during the current sampling window. A PSU with an unusually low InputPowerMin - for instance dropping toward zero briefly - while the server itself kept running normally on its redundant partner PSU, is a useful clue that the PSU itself, rather than the upstream circuit, momentarily lost input power. Comparing InputPowerMin across a PSU pair after a suspected power event can help distinguish a PSU-side fault from a facility-side outage.