Specifications
3
Most of the critical applications in data processing and other industries are now protected by Uninterruptible Power Supplies (UPS).
It is essential that the different types and performance levels are covered by international standards (IEC).
UPS systems are intended to improve the quality of AC power and provide a redundant (back-up) power source.
Power quality defects which may be improved by a UPS include surges, noise or sags.
In this type of UPS the load is isolated from the mains, hence all the power to the load ows through the inverter, offering continuous
protection and full isolation against surges, noise and sags. It offers true on line protection.
Simplied Diagram of an “Ofine“ UPS
This type of UPS is not suitable for all applications because it does not use a static switch bypass and the switching times are longer.
There is no isolation between the load and the mains. There is also no output frequency control.
Simplied Diagram of an “Line-Interactive“ UPS
This type of UPS does not provide isolation between the mains and the load. There is poor protection against spikes and poor efciency.
There is no output frequency control but it has voltage regulation on the output.
~
=
Rectifier/
Charger
=
~
Inverter
Battery
Static
Switch
AC
Input
Load
Filter
Load
~
=
Rectifier/
Charger
Battery
=
~
Inverter
AC
Input
=
~
Inverter
Battery
Transfer
Switch
AVR
AC
Input
Load
POWER CONDITIONING & UPS
OVERVIEWOFDIFFERENTUPSTYPES