Server racks are powered through a combination of direct electrical connections, power distribution units (PDUs), and backup systems. They typically use 120V or 208V AC power converted to 12V/48V DC for equipment. To understand how these systems work together, see our. An alternative approach to conventional alternating-current (AC) power uses a direct-current (DC) power distribution scheme throughout a data center. Most data center server racks are not currently powered this way, but with the advent of servers on the market that can operate with either AC or DC. While traditional data centers often rely on 250VAC single-phase power, today's high-voltage alternatives include 277VAC single-phase power, 480VAC three-phase power, and even +/-400VDC. The reason for the shift is simple. Data center managers are deploying more and more power to their IT equipment racks to keep up with power-hungry devices.
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