[TenTec] emergency back up power

[Eric F. Richards]

At 08:15 PM 3/5/2007 -0600, you wrote:

>An 85% efficient switching supply with that inverter gets you 72%
>overall. Nearly 30% losses. A common linear supply isn't that efficient
>with the unregulated voltage over 20 volts. At best 65% efficient. I do
>have a linear supply that I've measured 92% efficiency but it is picky
>about its input voltage and has no tolerance for low line voltage when
>loaded heavily. The FETs in it regulate down to .020 volts drop. They
>they go out of regulation. But the typical multiple transistor bipolar
>regulator has to have 4 to 8 volts drop to make the equalization
>resistors work.

Measuring an old Exel. SI-500 (12 V input), we ran the input from 10 to 17 
VDC and got 117 to 118 vac in a nice clean sine wave.  I don't know if you 
can do better than that...

Lest I be called a shill for Exeltech, I'm in the middle of private 
correspondence with an individual who has had a great deal of trouble with 
one of their inverters.  It sounds like QC has gotten sloppy there, or he 
got a lemon and they won't help him out.  Either way, not exactly a good 
sign...

Regards,

Eric, KB0YDN

--
Eric F. Richards
efricha at dim.com
"The weird part is that I can feel productive even when I'm doomed."
  - Dilbert