Lightning & Surge Technologies - Uninterruptible Power Supplies

With this type of UPS, the AC mains is the primary power source where any drop in voltage or battery current is automatically detected by the UPS, which switches over to the backup battery automatically. When AC power is restored, the UPS switches back to pas filtered mains and then recharges the battery.

The inverter is not connected in series with the AC mains, but rather in parallel configuration. There is transfer time associated with this changeover which is typically around four to ten milliseconds, which most computers switch mode power supply unit will not see this break.

Standby UPS often include a filter component, although this is more suited to EMI/RF, and surge protection provided through simple PCB Board mounted ow kA rated MOV components. This surge protection/ filtering is very ineffective at dealing with lightning transients which represent the greatest risk to connected equipment.

Note! Be aware that proper fit for purpose surge protection should be rated min Cat C (6 kV, 20 kA @8/20us), and should include a suitably tuned inductor component which can slow down the rate of voltage and current rise from reaching the connected equipment.

Do not confuse simple MOV and RF Filter as providing a good level of surge protection!!

You want to pay for cheap, you get cheap! Always remember that here is always a good reason why something is cheap, and generally there is a trade off in performance.