What your computer expects to get from the power grid is 120/127/208/220/230/240-volt AC power oscillating at 50/60 Hertz. A computer can tolerate slight differences from this specification, but a significant deviation will cause the computer’s power supply to fail. An uninterruptible power supply generally protects a computer against four different power problems:
1- Voltage surges and spikes – Times when the voltage on the line is greater than it should be
2- Voltage sags – Times when the voltage on the line is less than it should be
3- Total power failure – Times when a line goes down or a fuse blows somewhere on the grid or in the building
4- Frequency differences – Times when the power is oscillating at something other than 50/60 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 uninterruptible power supply UPS’s battery. A power inverter simply turns the DC power delivered by the battery into 120/127/208/220/230/240-volt, 50/60-Hertz AC power.
Continuous UPS
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 120/127/208/220/230/240-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
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.
RELATED SOLAR PRODUCTS
Prostar GT200K three phase 480Vdc true online ups power supply 200kVA |
Prostar PHR1103 19 inch server compact rack mounting online ups 3kva |