Re: UPS [Was:Re: Grand Apagon - Electricity (not) in Spain]

On 5/8/2025 7:18 AM, Martin Brown wrote:

On 08/05/2025 14:41, Carlos E.R. wrote:

On 2025-05-08 14:44, Carlos E.R. wrote:

 

UPS Topology: Standby (Offline) or Standby (Offline)

>
{Phrase translated by DeepL, so inconsistent: Topología UPS: En espera (Fuera de línea) o Standby (Offline)}

 There are (at least) two major UPS topologies in play.
 One is where the power to the protected device is always made by the inverter and maintained at the correct main voltage irrespective of input voltage to the UPS. Useful in places where the local mains supply voltage goes up and down a lot depending on load.

These are usually called "double conversion" (some call them "online"
but that can be misleading).
Most of these (that I've encountered) are less efficient (cuz they
are always in-the-loop) and often won't START without a functioning battery.

The other is a pass through of input mains voltage to the load under normal conditions and an isolation relay plus cold start of the inverter within a couple of cycles of the supply failure. This is more than good enough for PCs. Mine can withstand a 1s blackout unprotected without any difficulty but kitchen white goods clocks cannot.

These often can do some line voltage adjusting with an autotransformer
"for free" (part of the design).
They, also, are available in models that can be started only with a
valid battery or not.  Some require mains voltage to be present, as well.
There are also cheaper units that use "stepped" waveforms to approximate
a sine wave; others that are more religious in their determination.

I do not see a reference to that "topology" except at the vendor. But it says that the expected battery life is 4 years.

Ask for a guarantee on that... :>
[ObTrivia:  SWMBO's vehicle needed a starting battery replacement
~3 years after purchase (battery life is about that for all vehicles,
here; the heat cooks them).  As that was within the ~5 year "factory
warranty" period, it was no charge -- so I didn't bother to get
involved!
THAT battery, of course, failed 3 years later.  But, as it was
considered part of the original vehicle (despite being a replacement),
there was no warranty extended to it.
So, I went to Costco and bought one to avoid the dealer's insane
charges!]