PDU Power Management – Local Views with Remote Possibilities

Remote-PowerSometimes, let me rephrase that, most of the time, the network administrator has more than just the data center to manage (i.e. network closets, user systems, etc.) and if he only has local metering, he may not know when a particular load is exceeding capacity if he is not physically in the data center location. What can help with this? On-the-go power monitoring, or as the technical crowd calls it, remote power management, can help! Right away if you’re the network administrator your mind jumps to getting things done quickly and efficiently. To know your power needs, you have to have devices in place that can be monitored and managed remotely. This not only goes for the UPS, but also their output distribution sources such as PDUs. Having intelligent PDUs with remote monitoring and management brings certain advantages to the table depending on the functionality that you require. What are they? [Read more…]

What’s the Difference Between Basic and Smart PDUs?

PDUMNH20HVAT-FRONT-LA rack power distribution unit (PDU) is a device with multiple outlets designed to distribute power to networking equipment within a rack, including servers, storage devices and other equipment. For example, let’s say you have a 42U rack cabinet loaded with 42 1U servers, that’s 42 cords you have to find outlets for. PDUs solve this problem by taking the power supplied to the rack and distributing it via multiple outlets to the rack’s servers and networking equipment.

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The Best Solution for Providing Redundant Power to Your Rack that has Clustered 1U Servers

At capacities of 5kW and above, the most practical way to provide redundant power to 208V server racks has been to connect redundant 3-phase rack PDUs to redundant power supplies in each server. Until now… [Read more…]

Maximize Wall-Mount Rack Space with PDU/Ethernet Switch Combos

Wall-mounted racks are often used to organize and secure IT equipment at the edge of a company network, for example, in branch offices, classrooms, retail spaces and other remote locations. In recent years, the growth in cloud computing, powerful mobile devices, and the use of video for digital signage and security have required branch locations to access corporate resources and perform mission-critical functions previously available only at a headquarters location. [Read more…]

How Load Ramping Protects Data Center Power Systems from Inrush Overloads

Load ramping is an advanced feature of switched power distribution units (PDUs) and is used to protect data center power systems from inrush-related overloads by customizing the turn-on sequence of data center equipment. To better understand load ramping, a basic understanding of what causes inrush overloads is useful. Let me begin with a question: What are inrush overloads?

Inrush overloads are short-term overloads of a power system caused by the peak or inrush currents drawn by an electrical load at the moment it is energized. A simple example of an inrush current would be the turn-on of an incandescent light bulb. Before the light is turned on its filament is cold and has a low resistance to electrical current flow. When voltage is applied to the bulb, its low resistance allows a very high current to flow instantaneously. But as the filament heats up its electrical resistance increases. With an increased resistance, less current flows until it stabilizes to a steady state value. Inrush currents in data center equipment occur in a similar manner but on a much larger scale.

Some of the primary sources of inrush currents in data centers are power transformers, internal power supply units and electric motors. Electric motors can pull between 5 to 10 times of their rated full load amps (FLA) at turn-on. Depending on a variety of factors, the initial inrush of power transformers can be 8 times FLA. Additionally, the charging currents of input capacitors of power converters can cause inrush currents up to 20 times their rated current until they reach their fully charged, steady state value.

Inrush currents need to be addressed in the design phase of a data center’s power system because, if unaddressed, performance and reliability problems are likely to occur. Nuisance tripping or contact welding of circuit breakers are two possible outcomes. Voltage dips caused during transformer magnetization could affect the start-up of critical network equipment, which underscores the importance of line conditioning. Inrush currents can also thermally stress power converter components such as rectifiers, leading to the failure of the power supply unit itself.

There are different ways to address inrush-related overloads in data center power systems. Choosing the right type of circuit breaker and sizing it to handle peak currents is one way. Selecting equipment with internal current limiting is another. Load ramping addresses the problem of inrush overloads in a smart, convenient and cost-effective way.

Load ramping uses the capability of individual outlet control featured in switched PDUs and the programmability offered through power management software to customize the turn-on sequence of data center electrical loads so when they are energized, the cumulative inrush current of equipment in a common power system is reduced thus eliminating the risk of inrush overloads that can affect the availability of network equipment.

Tripp Lite offers load ramping capabilities in its Switched Power Distribution Units.