You will need

- The user manual uninterruptible power supply (UPS).

Instruction

1

Find the user manual of the selected uninterruptible power supply technical characteristics of its power consumption specified by the manufacturer in volt-amperes. This figure shows the maximum amount of power consumed by the device from the mains (that is, its full capacity). Even in this example, the full capacity of the uninterruptible power supply will be 1500 volt-amps.

2

Determine the efficiency of the uninterruptible power supply (power factor). It depends on the quality of the device and the number of connected electronics. The coefficient can range from 60 to 90%. For example, to the selected uninterruptible power supply will be connected to the system unit, monitor, laser printer, cash register. Efficiency is equal to 65% (0,65). Normal is the value of this coefficient for personal computers and office equipment at 0.6-0.7.

3

Turn the volt-amps to watts, calculate the power of the uninterruptible power supply according to the formula: V=VA*efficiency, where:

In - calculated active power in watts;

VA - power consumption of the device in volt-amperes specified by the manufacturer in the specifications;

Efficiency - the efficiency of the device (power factor).

In this example, the active power of the device in watts is equal to: 1500 (VA)*0,65=975 (watts). This figure describes the power provided by the uninterruptible power supply (active power consumption). The remaining 35% - a loss of power at the power supply.

In - calculated active power in watts;

VA - power consumption of the device in volt-amperes specified by the manufacturer in the specifications;

Efficiency - the efficiency of the device (power factor).

In this example, the active power of the device in watts is equal to: 1500 (VA)*0,65=975 (watts). This figure describes the power provided by the uninterruptible power supply (active power consumption). The remaining 35% - a loss of power at the power supply.

Note

Active power electric device will never exceed its full capacity. For some consumers of electric current, for example, for filament lamps, full power is equal to active, that is, its value in volt-amperes is the same as the value in watts.