If you change the power mode of the enclosure to AC redundant, the OA ensures that equal numbers of power supplies are available on the A and B sides as indicated in Figure 24. This logical grouping ensures that when the enclosure is configured with the three-phase AC input module, all the power supplies on one side maintain enclosure power if AC input power is lost on the other side. If you configure the enclosure power mode to N+1 or not redundant, you can install the power supplies in any bay. Figure 24.Connecting to PDUs with AC redundancy to each rack In an N+N AC redundancy configuration, the total power available equals the amount from the A or B side, whichever contains fewer power supplies. In this configuration, N power supplies are used to provide power and the same number are used to provide redundancy, where N can equal 1, 2, or 3. Any number of power supplies from 1 to N can fail without causing the enclosure to lose power. When correctly wired with redundant AC line feeds, this configuration will also ensure that a single AC line feed failure will not cause the enclosure to power off. Typical power configuration connecting to an uninterruptible power supply (UPS) In a configuration with N+1 power supply redundancy connecting to a UPS, the total power available equals the total power available less one power supply. In this configuration, there can be a maximum of six power supplies and one of them is always available to provide redundancy. In the event of a single power supply failure, the redundant power supply will take over the load of the failed power supply. Connecting with no power redundancy configured In a configuration with no power redundancy, the total power available equals the power available from all installed power supplies. Any power supply or AC line failure causes the system to power off if the remaining power supplies are unable to handle the full load. The OA manages power allocation rules of various components and can limit overall power capacity for the enclosure.
Technical white paper | HP BladeSystem c7000 Enclosure 27 Dynamic Power Saver mode Most power supplies operate more efficiently when heavily loaded and less efficiently when lightly loaded. Dynamic Power Saver mode provides power-load shifting for maximum efficiency and reliability. Dynamic Power Saver technology maximizes power supply efficiency to reduce operating costs. Power supply efficiency is simply a measure of DC watts output divided by AC or DC watts input. At 50% efficiency, 2000W input would yield 1000W output. The difference is costly wasted energy that generates unnecessary heat. Dynamic Power Saver mode is active by default because it saves power in most situations. When enabled, Dynamic Power Saver runs the required power supplies at a higher use rate and puts unneeded power supplies in standby mode. A typical power supply running at 20% load could have an efficiency rating as low as 60%. But at 50% load, the efficiency rating could be up to 94%, providing a significant savings in power consumption.