[PLUG] Recommended battery UPS?

[TomasK]

On Mon, 2021-05-03 at 17:00 -0500, Chuck Hast wrote:
> I have used the true sine wave version that is about 1000 VA
> to keep medical gear alive, Costco carries them some places
> in store but also on line.
> 
> I try to go sine wave, the power co's have really gotten trashy
> with the power now since appears that they no longer worry
> about keeping clocks and other gear disciplined.
> 
> The newer switching power supplies do NOT like the modified
> sine wave (lie lie... really modified SQUARE wave) that comes
> out of the non-sine wave boxen. I have lost a lot of lab gear in
> hospital labs because biomed insist on using modified sine
> wave rather than pure sine wave, have one hospital where I
> have had to replace 3 tissue processors due to that. It cost them
> but finally someone listened and replaced the stinking UPS with
> a real one that generated sine wave power....

What kind of person calls this modified sine wave:

         +--+            +--+            +--+     
         |  |            |  |            |  |
_    ____|  |____    ____|  |____    ____|  |____
 |  |            |  |            |  |
 |  |            |  |            |  |
 +--+            +--+            +--+

as suppose to square wave:

      +-------+       +-------+       +-------+
      |       |       |       |       |       |
------+       +-------+       +-------+       +-------+

blows my mind - no wonder switching power supplies do not like and
overheat in the best case.

-T