Some UPS units use watts (W) or kilowatts (kW) to represent their output power, such as 500W 1kw or other UPS uses volt ampere (A) or kilovolt ampere (kVA represents its output power, such as 3000VA, 5kA, etc. The general conversion relationship between VA and W is: watts are 0.8 times the volt ampere, such as 3K VI A=24k. UPS is used for line load power supply, and each type of UPS has a specific output power capacity. For example, a 3K VI A UPS has a maximum output power of 3K VI A or 24kw, which requires that the total power consumption of the devices connected to this UPS should not exceed 24 kilowatts. Usually, the devices indicate the power consumption (or rated power) At this point, it is necessary to ensure that the combined rated power of all devices connected to the UPS does not exceed the output power of the UPS. This method is usually called the matching of UPS output power and load power consumption. But some devices have a startup power of 35 times the rated power (for example, if the rated power of a printer is 200W, then when calculating load matching, it is necessary to press 5 × 200W=1000W for conversion). Except for printers, other computer external devices usually have a startup power slightly higher than the rated power. Therefore, when considering matching, it is best to match the load at 80% of the UPS output power. Before the standard UPS is equipped with an external battery, if its output power matches the load power consumption completely (i.e., in the case of a full load ship, it can supply power for about 6-10 minutes from the time of mains power interruption. The specific values are recorded in the UPS manual of each model), if the load power consumption is only half of the UPS output power (commonly referred to as half load or 50% load rate, such as a 1000W UPS connected to a 500W load), it can supply power for 1225 minutes, The UPS power supply time at different load levels can be calculated approximately by doubling the load reduction time. Proper use of UPS power supply can not only reduce the chances of UPS failure, but also effectively extend its service life.