THE PROBLEM AND THE SOLUTIONS

Electronic and information systems are essential elements of our everyday lives. More and more processes in our environment are controlled electronically and information is fundamental in the workplace.

Power companies face an ever-increasing demand for energy and cannot always ensure the quality or uninterruptible nature of the power supply. This results in an average of 280 micro cut-offs per day, variations in voltage and power cuts, causing possible damage to equipment or the halting of production. Thus, any system or electronic product which plays an important role in our lives should be protected. Such is the case with lifts - to ensure that we are not trapped between floors, or computers - to ensure that we do not lose a day or a week's work.

UPS (Uninterrubtible Power Supplies) are systems which accumulate energy and verify the voltage of the power supply. They basically consist in a battery which stores energy, a charger to charge the battery, and an inverter to convert the accumulated direct energy into alternating energy. A number of different filters are also normally included. Depending on the technology used the product adapts better to our needs and different solutions may be found for different uses.

• Online technology: These systems supply the connected loads using the energy accumulated in the battery. If connected to the power supply they charge the battery whilst supplying the connected loads from the battery. If there is no power supply they do not charge the battery and continue to supply the equipment from the battery. There is no cut-off time and so they aremore reliable than interactive technology devices. They normally provide a sinusoidal output signal. The output voltage is also normally more precise. They are normally used for servers, complete system installations and high consumption or critical machines.

• Interactive Technology: These systems normally use the electrical current itself to power the equipment connected to the UPS. When they detect an anomaly in the electrical supply, the energy is supplied from the battery.
  Their main feature is that for a very short period of time the system does not receive an electrical supply. This moment is normally called the cut-off time. It normally only lasts a few milliseconds and most IT and electronic systems are not effected by the cut-off as they have a small level of accumulated energy ( hold-up time).
  The type of output wave generated may vary.
  Some device have a a pure sinusoidal output wave and others provide a modified sinusoidal wave. Devices with modified sinusoidal wave output generate a trapezoid wave. Most electronic devices accept this type of signal. Nevertheless, some devices, such as oscilloscopes, analyzers, etc. may require a pure sinusoidal wave. These devices also have a small filter system for the input signal. Used mainly with personal computers and smaller machines.