UNDERSTANDING UNINTERRUPTIBLE POWER SUPPLIES

This type of UPS consists of a basic battery/power conversion circuit and a switch that senses irregularities in the electric utility. The equipment to be protected is usually directly connected to the primary power source and power protection takes place only when the voltage dips to the point of creating an outage. If the UPS is forced to go to battery frequently, it can drain the battery, making it unavailable during blackouts. They do not protect against sags, line noise, frequency variation or brownouts unless the battery is delivering power to the protected system.

This type of UPS is a hybrid device that offers a higher level of performance by adding better voltage regulation. With power sags, line interactive UPS may use a tapped transformer to provide the voltage levels needed to maintain output voltage. Essentially, the unit switches to battery to adjust the tap location at set intervals to maintain the output voltage as the input voltage falls. It will eventually go to battery full-time once the input voltage reaches a pre-selected level. If the UPS is forced to go to battery frequently, it can drain the battery, making it unavailable during a power outage. They provide moderate protection against high voltage spikes and switching transients, although, again, not with complete isolation.

This type of UPS offers the highest level of power protection. This type uses the combination of a double conversion (AC to DC/DC to AC) power circuit and an inverter, which continuously powers the load to provide both conditioned electrical power and outage protection. It also offers complete protection and isolation from all types of power problems-power surges, high-voltage spikes, switching transients, power sags, electrical line noise, frequency variation, brownouts and blackouts. These types are used for mission critical application that demand high productivity and system availability.