There are several Uninterruptable Power Supply (UPS System) technologies available, all of which have various pros and cons. This article intends to help guide you in the correct choice for your required application. All GE UPS Systems consist of a rectifier which converts your standard mains AC power into DC power, an inverter that converts DC power into AC power, and an energy storage medium which is usually lead acid batteries.
There are three main UPS technologies – Offline, Line Interactive and Online Double Conversion – and two different types of the inverter – square wave (also called pseudo-sine wave or modified sine wave) and sine-wave.
An Offline UPS provides basic levels of power protection. There is usually a degree of surge suppression incorporated, and when the input mains voltage goes out of tolerance (that is too high/low or fails), the UPS inverter starts up and provides power to your equipment. There is a break in the mains supply when this occurs in the region of 10-20 thousands of a second which will go unnoticed by the majority of equipment. The inverter in offline UPS is nearly almost always a square wave.
A line interactive UPS is similar to an offline UPS but has the added benefit of voltage regulation. This means that it will reduce the mains voltage if it goes too high (called “buck”) or raise the mains voltage when it goes too low (called “boost”). It will do this without reverting to a battery and hence conserve battery life. Since a line interactive UPS has an inline transformer, it also provides inbuilt filtering and hence a higher degree of power protection. Like the offline types, there is also a break during the transition from mains power to battery power. In higher quality line interactive units, this break may be as low as only 2 to 4 thousandths of a second. Line Interactive GE UPS Systems come with a square wave as well as sine wave inverters.
The online double conversion GE UPS system is considered by many to provide the highest levels of power protection. The inverter is always on and provides power to the load. This means that there is no deviation in output voltage and no break if the UPS reverts to battery power. The output waveform in an online UPS System will almost always be a sine-wave, generally of very high quality and can enhance the operation of certain equipment. An online double conversion UPS also has a bypass circuit, which allows power to be continually fed to your load even if the UPS develops a fault or is overloaded.