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ITGlossary · UPS technology
Modular UPS
A UPS design where independent modules can be combined to meet power and redundancy needs.
Technical level:Intermediate
A modular UPS consists of a frame (rack) with shared distribution and slots for power modules, each providing a certain number of kW. The modules share the load, and if one fails the others carry on. Modules can usually be replaced while running, without interrupting the load.
The main advantage is scalability: you start with the power you need today and add modules as the load grows. With one module more than required (N+1 redundancy), the system can lose a module without losing protection.
When designing, size the frame, cabling and protective devices for the final capacity, not the initial one. Otherwise, a future expansion will require new electrical work.
Related articles
Related terms
- RedundancyHaving more UPS units or modules than the load needs, typically in an N+1 or 2N configuration, so the load stays powered if one fails.
- ScalabilityThe ability of a UPS system to expand capacity by adding additional modules or batteries.
- Redundant Power SupplyA second power supply inside a server or switch that takes over without interruption if the first one fails or loses its feed.
- Six Nines AvailabilityAvailability of 99.9999%, about 32 seconds of downtime a year, which requires redundancy across the whole power chain.
- Zero Transfer TimeA feature of online UPS systems, where the inverter feeds the load continuously so a power cut causes no gap at all.
- AC EfficiencyIndicates how efficiently a UPS converts incoming AC power into usable output power during normal operation.