What is the difference between the PDU power supply used in a computer room and a regular power supply?

1. What is the working principle of a rack-mounted PDU?

While there are many subtle differences in how rack-mounted PDUs operate, the basic concept is not complex. Rack-mounted PDUs manage and distribute power, typically mounted directly on the rack. They draw power from the rack power supply (branch circuit) and distribute power from uninterruptible power supplies, utility power, generators, or other auxiliary power sources (which can be AC or DC) to the various outlets on the PDU itself as needed. In short, a rack-mounted PDU is essentially a single power input converted into multiple power outputs.

2. Several factors related to rack PDUs

When selecting rack PDU socket products based on actual application needs, factors such as voltage, phase, plug, socket type and function need to be considered. Different variables will result in many types of rack PDU products.

(1) Branch circuits: Power is distributed to server racks and cabinets via distribution boards, switches, or distribution panels. Cabling can run under raised floors, in overhead bus systems, or both, and terminate at outlets near server racks and cabinets. The load capacity of a branch circuit is measured in volt-amperes (VA) or kilovolt-amperes (kVA) and is calculated by multiplying the rated voltage by the rated current.

(2) Voltage and number of phases: In terms of power input, standard rack PDUs usually support single-phase or three-phase power input. The appropriate input voltage needs to be selected based on the actual conditions of the server room and the mains voltage. Common input voltages are 110V, 200V, and 380V, with frequencies of 50Hz or 60Hz.

(3) Output current and PDU plug type: The output current of a rack PDU needs to be determined based on the type of end device. Standard PDUs usually provide multiple output sockets to support the power supply of different devices. Common output socket types include national standard 16A, 10A, C13, C19, NEMA , etc., to accommodate different types of IT equipment. Therefore, understanding the types of equipment in the server rack or cabinet, as well as the type and number of sockets, is very important.

(4) Functional Configuration of Rack-Mounted PDUs: Rack-mounted PDUs can be equipped with various functional components, such as surge protection, filtering protection, overload protection, and current and voltage display modules. Currently, the new generation of intelligent PDUs also provides users with multiple control methods, including local control and remote control. Local control is usually achieved through buttons or switches on the PDU device, allowing manual control of power supply switching and current distribution. Remote control is usually achieved through network connections, allowing remote control of the PDU device via Web interface, SNMP protocol , Telnet protocol, etc., to achieve remote power monitoring and management.