3. Recognize the type of input socket
After we have completed the consideration of the interior of the rack, we need to consider the overall power distribution of the rack column. Admit the voltage of the on-site power supply (such as 208V, 240V, etc.) and acknowledge that the power supply connected to the rack is single-phase or three-phase. The specific information about the advantages of three-phase power supply access, on-site distribution plan (voltage and phase number), and estimated power demand will determine the input power lines, cable currents, or amperes required for the lamp rack. In order to alleviate the danger of overload to the normal operation of IT equipment, the general practice is to have the amperage of a single-phase PDU<40A or the amperage of a three-phase PDU<32A. Rack mounted PDUs with amperage higher than the above values will put most equipment at risk of corresponding circuit breaker overload. If there is a greater power demand within a single rack, additional PDU components need to be installed. The best practice is to choose rack mounted PDUs with<20A as much as possible, as these PDU products do not include circuit breakers, which can reduce the use of one component in the power path and help improve system reliability. This circuit has always been protected by an upstream 20A circuit breaker. Similar to regions using 230V voltage, countries using 120V voltage can convert the voltage to 240V. Compared to 120V voltage, 240V voltage can provide twice the power supply for a 20A circuit. Generally, rack mounted PDUs offer a variety of cable lengths to choose from. When selecting, it is necessary to choose products with suitable cable lengths to ensure satisfactory slack, so that the power cord plug can be easily connected to the power socket for protection. Generally speaking, a cable length of 2 meters (6 feet) is sufficient to connect the power plug to the input distribution end.
Suggestion: Choose rack mounted PDUs of 16A and 20A as much as possible, as they are easy to operate, highly reliable, and have a simple layout. The rack mounted power distribution unit equipped with three-phase power supply can provide additional power capacity for future load expansion.
4. In addition to monitoring the overall power consumption trend of the rack over a long period of time, the visualization function and control options of the selected branch can also monitor the power status and instantaneous power consumption status of the rack mounted PDU. According to the visualization level of rack power status, it can be divided into three categories: fundamental level, monitoring level, and metering level. Fundamental level visualization does not provide any information about power consumption status. In this view, the rack may be on the brink of tripping, but no one is aware of it. Monitoring level visualization provides a display screen that displays real-time information. These pieces of information can assist in recognizing phase balance and fundamental loop load conditions, but can only provide an instantaneous information. The decision plan based on the above information cannot take into account factors such as peak usage or cyclical trends. These facilities cannot display signals only on local display screens, and cannot announce alarm information to I operators during high-risk situations.
For data centers, when the circuit is approaching its maximum capacity and the circuit breaker is facing the risk of tripping, metrology level visualization provides a useful way to grasp these conditions. The metering PDU is equipped with an intelligent network processing chip. When the load approaches the preset threshold upper limit, it can announce an alarm through email, SMS, visual alarm information on the display screen, and other means before the problem occurs. I operators can analyze power consumption trends based on the stored data of power consumption history, and then make the best decision plan to determine where to install new equipment, balance the circuit load, and avoid overload hazards. This automatic planning is a useful measure for eliminating downtime caused by circuit breaker tripping.
Some rack mounted PDUs have the function of measuring a single socket, not just measuring branches. So far, although most data centers are not yet ready to use this advanced method to monitor the internal power consumption of racks at a deeper level, this technology is indeed a powerful tool for IT professionals to assist them in better energy management.
Most rack mounted PDUs can also measure other variables in the operating environment. Generally speaking, the rack mounted PDU can connect temperature sensors and humidity sensors. PDU can display the measured temperature and humidity information on the display screen, and can also be stored or transmitted to other places through the network. Temperature is the primary cause of equipment malfunction and shutdown, second only to power outages. The temperature sensor inside the rack can be connected to the rack PDU to ensure that the server and other I devices operate in a normal environment.
Suggestion: If there is no dedicated metering equipment upstream of the rack mounted PDU branch, it is recommended to use a metering rack PDU.