Three-phase power is an electrical system that combines three separate currents that alternate but have the same frequency of 120 degrees, delivering power that works more efficiently in industrial power systems than single-phase electrical systems, according to Tripp Lite. The current in a three-phase power supply is constant.
Because a three-phase power system has the ability to deliver more efficient power, it should only be used if a single-phase power circuit cannot handle the load of a large system, such as a data center, states Tripp Lite. Most electronics are powered with a single-phase power circuit for this reason, as such electronics do not require constant currents. A three-phase power supply is able to deliver a constant current because its power does not carry the risk of falling to 0. In contrast, the power in a single-phase power supply drops to zero three times per cycle.
Because the three-phase power distribution cabinets that manufacturers produce can power multiple server racks at once, using three-phase power over single-phase power can be a more efficient option for data centers, as claimed by Tripp Lite. Single-phase circuits must be installed on each individual rack, which means that installing one three-phase circuit for multiple server racks cuts labor costs. Data centers also save on costs by having less equipment to keep cool.