At input side, there will be an instant (1/2 ~1 cycle, ex. 1/120 ~ 1/60 seconds for 60 Hz AC source) large current (20~ 60A based on the design of S.P.S., please refer to the spec. sheet) appears at the moment of power on and then back to normal rating. This "Inrush Current" will appear every time you turn on the power. Although it will not damage the power supply, we suggest you not to turn on/off the power supply very quickly in the short time. Besides, if there are several power supplies turning on at the same time, the dispatching system of AC source may shut off and go into protection mode because of the huge inrush current. It is suggested that these power supplies should start up one by one or use the remote control function of S.P.S. to turn them on/off.