Best UPS (Uninterrupted Power Supply) for you.

What is UPS (Uninterrupted Power Supply).

UPS provides backup power for a computer when the electrical power fails. Different models offer different levels of protection. The amount of time the battery can provide power varies with the model of the UPS. Small UPS units are equipped with a battery and a sensor (which detects the loss of power). If the sensor detects a loss of power, it immediately switches over to battery so that the user has enough time to save his or her work and shut off the computer. But, high-end UPS models offer longer battery time.

   There are five types of UPS:

1. Standby
2. Line Interactive 
3. Standby-Ferro 
4. Double Conversion On-line
5. Delta Conversion On-line

• Standby UPS 

It is the most common type of UPS used for computers. The transfer switch is set to choose the filtered AC input as the primary power source (solid line path), and switches ti the battery/inverter as the backup source should the primary power source fails. When that happens, the transfer switch must operate to switch the load over to the battery/inverter backup power source.

• Line Interactive UPS

The Line Interactive UPS connection is the most common design used for PCs. In this design, the battery-to-AC power converter (inverter) is always connected to the output of the UPS.

  Operating the inverter in reverse during times when the input AC power is normal provides battery charging. When the input power fails, the transfer switch opens and power flows from the battery to the UPS output.

  The Line Interactive design incorporates a tap-changing transformer. This adds voltage regulation by adjusting transformer taps as the input voltage varies. Voltage regulation is an important feature when low voltage conditions exist. High efficiency, small size, low cost and high line voltage condition make this the dominant type of UPS in the 0.5-5 kva power range.

• Standby Ferro UPS

Standby Ferro UPS has three windings (power connections). The primary power path is form AC input, through a transfer switch, through the transformer, and to the output. In case of a power failure, the transfer switch is opened, and the inverter picks up the output load. In the Standby Ferro design, the inverter is in the standby mode, and is energized when the input power fails and the transfer switch is opened. The transformer has a special "Ferro -resonant" capability, which provides limited voltage regulation and output waveform "shaping". The isolation from AC power transients provided by the ferro transformer is as good as or better than any filter available. But the Ferro transformer itself creates severe output voltage distortion and transients, which can be worse than a poor AC connection.

  Standby Ferro UPS are quite arge and heavy. High reliability and excellent line filtering are its strengths.

• Double Conversion On-line UPS

The Double Conversion On-Line It is the same as the Standby, except that the primary power path is the inverter instead of the AC main.

  In this design, failure of the input AC does not cause activation of the transfer switch, because the input AC is charging the backup battery source which provides power to the output inverter. Therefore, during an input AC power failure, on-line operation results in no transfer time. both the battery charger and the inverter convert the entire load power flow in this design, resulting in reduced efficiency with increased heat generation.

  This UPS provides a nearly ideal electrical output performance. But the constant wear on the power components reduces reliability over other designs. The energy consumed by the electrical power inefficiency is a significant part of the life cycle cost of the UPS. Also, the input power drawn by the large battery charge is non-linear and can interfere with building power wiribg or cause problems with standby generators.

• Delta Conversion ON-Line UPS

Delta Conversion On-Line UPS is a newer technology introduced to eliminate the draw-backs of the Double conversion On-Line design. It is available in size ranging from 5 KVA to 1.6 MW. It always has the inverter supplying the load voltage. The additional Delta Converter contributes power to the inverter output. Under condition of AC failure or disturbances, this design exhibits behaviour identical to the Double Conversion On-Line.