Newps wrote:

Mike 'Flyin'8' wrote:

UPS are usually designed to come online within a couple of cycles.


I have never seen a UPS that takes more than a fraction of a cycle to
transition to backup mode.

We have UPS's in the tower and TRACON. They work only when properly
maintained. Ours are not and it's a 50/50 bet that the entire
tower/TRACON will reset when they don't work. If they don't work it's a
10-15 second deal while everything comes back on line. That's why we
always manually turn on the back up generators whenever there are
thunderstorms in the area.

In fact, units which are used in "mission
critical" applications are not the line interactive type as you seem
to be thinking about above, instead are dual online conversion. I
would assume that a UPS used for ILS equipment and radio
communications for ATC would be a mission critical design as opposed
to the less than reliable line interactive design.

They are not.

If you keep posting facts instead of idle speculation you're going to
ruin USENET.