Standby On-Line Hybrid. The Standby On-Line Hybrid is the topology used for many of the UPS under 10kVA which are labeled "on-line." The standby DC to DC converter from the battery is switched on when an AC power failure is detected, just like in a standby UPS. The battery charger is also small, as in the standby UPS.
White Paper # 1: The Different Types of UPS Systems. Executive Summary. There is much confusion in the marketplace about the different types of UPS systems and their characteristics. Each of these UPS types is defined, practical applications of each are discussed, and advantages and disadvantages are listed.
In addition, the Delta Conversion On-Line UPS offers reduction in energy losses and costs by approximately a factor of 4. As a side-effect of the design, the input power quality of the Delta Conversion UPS is also superior, particularly in the large kVA sizes.
Double Conversion On-Line UPS is the same as the Standby UPS except that the primary power path is the inverter instead of the AC mains. In the design of Double Conversion On-Line operation, failure of the input AC does not cause activation of the transfer switch, because the input AC is not the primary source, but is rather the backup source.
During an outage, line-interactive UPS systems typically transfer from line power to battery-derived power within two to four milliseconds, which is more than fast enough to keep all but a small percentage of the most power-sensitive equipment operating without interruption.
At one time, the Standby-Ferro UPS was the dominant form of UPS in the 3-15kVA range. This design depends on a special saturating transformer that has three power connections. The main power supply comes from AC input, through a transfer switch, then through the transformer and to the output.
Different UPS types are appropriate for different applications, and that there is no single UPS type that is ideal for all applications. With the variety of UPS topologies on the market today, these guidelines will help clear confusion about how each topology operates and the advantages and disadvantages of each.