1, first of all, to determine the equipment of your data center is the need for how much power, generally speaking, the power of the ordinary PC or industrial control machine in 200W or so, Apple in 300W or so, servers in the 300W and 600W between the power value of other equipment can refer to the manual of the equipment. Just buy it as required.
2, secondly, should understand the UPS power rating there are two ways to express: apparent power (unit VA) and the actual output power (unit W), due to the presence of reactive power so caused by this difference, the two conversion relationship is: apparent power * power factor = actual output power. So in the purchase of the time to calculate.
3, UPS is usually divided into two types of industrial frequency machine and high frequency machine. Industrial frequency machine by silicon controlled SCR rectifier, IGBT inverter, bypass and industrial frequency step-up isolation transformer. Because of its rectifier and transformer operating frequency are industrial frequency 50Hz, as the name suggests called industrial frequency UPS. above is the choice of a few points, I hope to help you.