What is a UPS?
A UPS is not designed just to overcome power cuts. Its role is also to stabilize electrical power and remove interference.
The UPS is an important link in the safety of information systems. Its main task is to take over when mains power cuts occur, giving users time to save work in progress.
Power cuts are not the only incidents that these devices have to deal with. Voltage regulation and filtering are another important function.
A good UPS should ensure an uninterrupted power supply to equipment but also provide high quality power.
A UPS has three parts:
- The rectifier which transforms alternating current to direct current designed to charge batteries and power the UPS.
- The batteries that store the energy.
- The UPS that transforms the direct current delivered by the rectifier or batteries to 230-Volt power at 50 Hz, identical to the mains power supply.
How to choose the right UPS for you?
Step 1 - Know how to calculate the power required by your installation:
- Take note of the consumption in Amperes, Watts or VA on each device to be protected.
- Calculate the sum of all the recorded values (in the same units).
- Choose a UPS with a higher capacity than the sum of the connected loads.
Notes: If the values are expressed in Amperes, multiply by 230 to obtain VA (Example: 7.5 A x 230 V = 1725 VA). If the values are expressed in Watts, divide by 0.7 to obtain the equivalent in VA.
Formulae:
Apparent power = Voltage x Current
VA = V x A
Effective power = Apparent power / cos (power factor)
W = VA / [coc (power factor)]
Note: In general, it can be considered that the cos (power factor) has a value of 0.70
It is important to make sure that the load supplied is not greater than the UPS capacity.
