{"id":"ups","level":"datacenter","name":"Uninterruptible power supply and backup chain","shortName":"UPS","role":"Maintains power continuity across disturbances and transitions to other supply sources.","description":"An uninterruptible power supply supports critical loads when incoming electrical supply is disturbed. Stored energy and power electronics can bridge a gap until a generator or other source becomes available, or permit controlled shutdown according to the facility design. Runtime is finite and depends on load, stored energy, and equipment configuration. The atlas traces normal supply and backup paths separately, making the transition understandable without implying that a battery can power a data center indefinitely. Modern power-management arrangements may also help handle changing loads, but capabilities vary. UPS systems belong to a wider chain of distribution, protection, generation, and monitoring that must deliver reliable power to the rack shelves downstream.","specs":[{"label":"Purpose","value":"Power continuity","context":"Supports disturbances and source transitions."},{"label":"Runtime","value":"Load- and configuration-dependent","context":"No universal minutes-of-backup specification."},{"label":"Power vs energy","value":"kW vs kWh","context":"Delivery rate and stored amount are different quantities."}],"interfaces":[{"name":"Utility or backup source","direction":"in","signal":"Electrical supply"},{"name":"Critical distribution","direction":"out","signal":"Conditioned or supported power to downstream loads"}],"tradeoff":"More backup duration improves endurance. Stored energy, conversion capacity, and maintenance require resources.","whyAI":"Long AI jobs lose progress when power disappears. Continuity and checkpoints address complementary parts of that recovery problem.","related":["power-shelf","checkpoint","rack"],"sources":[{"title":"Eaton — UPS and Data-Center Infrastructure","url":"https://www.eaton.com/us/en-us/markets/data-centers/data-center-infrastructure-overview.html"},{"title":"Eaton — UPS Bridging Generator Startup","url":"https://www.eaton.com/us/en-us/catalog/backup-power-ups-surge-it-power-distribution/eaton-9355-ups/data-center-solutions-for-continuous-uptime.html"}],"scale":"Room-scale power infrastructure; conceptual supply paths","kind":"ups","mechanism":["Supply critical loads during normal operation.","Use the supported stored-energy path when supply is disturbed.","Bridge to another source or a controlled operational response before the available runtime is exhausted."],"misconception":"A UPS power rating in kW does not specify its energy capacity or runtime in hours.","check":{"question":"What chiefly determines backup duration?","options":["The color of battery cabinets","Stored usable energy and the supported load","The number of training tokens already processed"],"answer":1,"explanation":"Energy divided by load gives basic duration intuition, with equipment limits and losses affecting actual runtime."},"branch":"Electrical infrastructure","subbranch":"Continuity and backup","science":[{"title":"Finite backup duration","equation":"t_runtime ≈ E_usable η / P_load","explanation":"Stored usable energy divided by the supported load gives a first duration estimate. Conversion losses and runtime-dependent battery behavior affect the actual result.","assumptions":"Constant load and effective usable energy approximation; vendor discharge curves, reserve limits, temperature, and aging are required for engineering sizing."}],"history":[],"prerequisites":["power-supply"],"learningObjective":"Estimate an ideal backup runtime from usable energy, conversion efficiency and load.","engineeringExample":"Synthetic UPS: 100 kWh usable stored energy, 90% conversion efficiency and constant 300 kW load give 100 × 0.9/300 = 0.3 h = 18 min. A 600 kW load would give 9 min under the same ideal assumptions.","evidenceNotes":"This is a constant-load energy estimate, not battery sizing or a vendor runtime guarantee. Discharge curves, reserve, temperature, aging, transient load and power-delivery limits require configuration-specific data.","labId":"library","scope":"No current calculator directly models this lesson’s main mechanism. Use the library for related bounds while retaining their stated omissions.","investigationId":"manufacturing","labScope":"No current calculator directly models this lesson’s main mechanism. Use the library for related bounds while retaining their stated omissions."}