There are Stand-By/Line-Interactive UPS, and Online UPS.
The Stand-By/LI UPS charges and keeps the battery charged up, and in the event of a power failure will flip over to Battery mode usually in <25ms
The Online UPS will have two separate pieces of circuitry whereby it will charge the battery. Then it inverts from the battery to AC output. There is no switching involved as it is 'always' running on DC power. The Battery is maintained at full charge during this process. In the event of a power failure, there is no flipping over to DC, it's already there. These are far more expensive units.
Pros/Cons:
Stand-By/LI - Cheaper, lighter, smaller footprint. Possible for surges/brownout to happen during switching. Lights could easily been seen dimming on some units.
Online - More expensive, heavier, larger footprint. No brownouts/surges. All power is filtered even from the grid so no noise or power ripple on the load side
UPS Technologies When choosing a UPS (Uninterruptible Power Supply) to protect your electronic equipment there are 3 main UPS technologies on the market today. The standby UPS is a low cost option that will protect you from power failure, sags and surges, while an online UPS offers total power...
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