What kind of load should I use with UPS/inverter?

Usually we assort loads into three types: resistive load, capacitive load & inductive load, actually there is seldom single capacitive or inductive load, and most of them are combines. General speaking, we suggest you to select low frequency UPS/inverter for capacitive or inductive load, furthermore, if your power condition is terrible, absolutely you should choose low frequency type, usually high frequency UPS/inverter are used in a good power grid.