Uninterruptible Power Supply

UPS is a critical part of the QuickFuel system. Following is an explanation of the functions performed by a UPS and why it is extremely important to ensure your system is protected from dirty power.

An uninterruptible power supply (UPS), also known as a battery back-up, provides emergency power and, depending on the topology, line regulation as well to connected equipment by supplying power from a separate source when utility power is not available. It differs from an auxiliary or emergency power system or standby generator, which does not provide instant protection from a momentary power interruption. A UPS, however, can be used to provide uninterrupted power to equipment, typically for 5–15 minutes until an auxiliary power supply can be turned on, utility power restored, or equipment safely shut down.

While not limited to safeguarding any particular type of equipment, a UPS is typically used to protect computers, data centers, telecommunication equipment or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption or data loss. UPS units come in sizes ranging from units which will back up a single computer without monitor (around 200 VA) to units which will power entire data centers or buildings (several megawatts).

How a UPS works

What your computer expects to get from the power grid (in the Australia) is 240-volt AC power oscillating at 60 Hertz. A computer can tolerate slight differences from this specification, but a significant deviation will cause the computer's power supply to fail. A UPS generally protects a computer against four different power problems:

• Voltage surges and spikes - Times when the voltage on the line is greater than it should be
• Voltage sags - Times when the voltage on the line is less than it should be
• Total power failure - Times when a line goes down or a fuse blows somewhere on the grid or in the building
• Frequency differences - Times when the power is oscillating at something other than 60 Hertz

There are two common systems in use today: standby UPS and continuous UPS. A standby UPS runs the computer off of the normal utility power until it detects a problem. At that point, it very quickly (in five milliseconds or less) turns on a power inverter and runs the computer off of the UPS's battery (see How Batteries Work for more information). A power inverter simply turns the DC power delivered by the battery into 120-volt, 60-Hertz AC power.

In a continuous UPS, the computer is always running off of battery power and the battery is continuously being recharged. You could fairly easily build a continuous UPS yourself with a largish battery charger, a battery and a power inverter. The battery charger continuously produces DC power, which the inverter continuously turns back into 120-volt AC power. If the power fails, the battery provides power to the inverter. There is no switch-over time in a continuous UPS. This setup provides a very stable source of power.

Standby UPS systems are far more common for home or small-business use because they tend to cost about half as much as a continuous system. Continuous systems provide extremely clean, stable power, so they tend to be used in server rooms and mission critical applications.

Information has been obtained from Wikipedia.