Compaq BL10e Power basics for IT professionals - Page 19
Distribution within the rack, means an in-rack power strip.
UPC - 613326445501
View all Compaq BL10e manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 19 highlights
requires four PDUs. Since each PDU requires two poles off the distribution panel to get 208 V, each cabinet requires four breakers and eight poles. With these requirements, the 84-pole panel will provide redundant power for 10 cabinets and 210 servers using today's distribution method. A 10cabinet implementation will use only 86 kVA of the 150 kVA possible from the panel. In this example, there are not enough poles to pull additional power, and more than 40 percent of the total available power could be left at the panel. A three-phase solution typically uses fewer distribution panel connections. Using three-phase power distribution to the rack, with a single to three-phase PDU such as the HP 8.6kVA Modular PDU, only two three-phase 30A circuits are required per rack. Each three-phase 30A circuit uses two breakers and six poles per rack. With 84 poles, the panel can now power 14 racks using 120kVA of the 150kVA or 80% percent of total available panel power. Moreover, using fewer power cables and PDUs would simplify installation and troubleshooting. Distribution within the rack From the server room power panel, power goes to the racks of servers throughout the room. A wire from each circuit breaker provides power to each outlet where the equipment connects. As long as the power provided is sufficient for the equipment in place, this system is adequate. However, if the outlets, wire, and breakers need to be upgraded for higher amperage or for three-phase power, the process can be very expensive and time consuming. HP recommends using PDUs in installations where a number of servers can place serious loading demands on the power infrastructure. The term PDU can refer to two different distribution points: the transformer unit for the entire floor or an in-rack PDU supporting power strips. In this paper, PDU means an in-rack power strip. Several considerations that can drive PDU selection: • What types of power cables are required? • How many power cables are required? • What are the specific current requirements for each piece of equipment? • What is the total current requirement for all equipment? The actual total current requirement should not exceed 80 percentage of the rated amperage of the PDU or the individual circuit of each PDU. HP modular PDUs integrate the outlets, wire, and breakers in a convenient location on each rack. These PDUs provide from 16A to 60A three phase, with up to 32 receptacles. 19