UPS = Uninterruptable Power Supply 

A ups Integrates batteries to allow constant power supply. The major role of a ups is to provide electrical protection to all production equipment (IT, industrial, etc.). 3 existing technology levels:

➢ Off-Line technology: basic

The equipment is normally powered and the ups only takes over in the event of an outage, or too large a drop in the mains voltage. The battery switching takes a few milliseconds which is not too inconvenient for computers with switching power supplies, but it can cause problems for more sensitive equipment.

➢ Line-interactive technology:

The principle is the same as Off-Line, except that the input voltage is controlled and filtered by the ups before being delivered to the equipment. The current supplied is therefore of better quality, but voltage variations are not well regulated. It includes an internal Automatic Voltage Regulator (AVR) for better compensation of the voltage fluctuations and to avoid a greater use of the batteries and so prolong their life time. As a result, this type of UPS should not be used in the company's vital servers.

➢ On-Line technology:

On-Line double conversion, the power is continuously delivered by the ups, which guarantees a constant voltage and an absence of interference. The device to be protected is therefore completely disconnected from the mains. Tests show that On-Line ups have the most stable output voltage and immunity to parasites. They will therefore have to be used on all strategic and sensitive servers.