Hi Day Brown, hope you are having a nice day
PW>>  Dunno about that. I've seen iso-xfrmrs for under $50US with 2KW
DB> I find a 1500watter at 60$... that weighs almost 20 lb. your 2kwatter 
DB>probly run 25, whazzat another 15-20$ shipping. shouldda defined my 
DB>idea of expensive.  Big, being 6X6X6. izzat big? whatever. 
 6 by sounds about right for a couple of K. And shipping is always 
a bear. 
DB> As I told Roy, my problem is with the PWM chips in the new designs 
88
DB>it's own idea of what the sin wave should look like, ... 
 That's why a UPS with a ferro-resonant xfrmr is such a good thing.
The one I have here uses SCR's to switch the 48V feed and uses a
PWM. IOW, the input is a full blown square wave. Square waves work,
but among other things, they're noisy as all get out. Ringing, harmonics
all over the rf bands... You name it. Now if you use a regular 
transformer your output, no matter what it's controlled by, is gonna
look like crap.
 Otoh, if it's put thru a ferro-resonant, it'll be as clean as
what comes from your local powergrid.  PWM controllers, or any
other kind not withstanding. The design of a ferro-resonant
eliminates a large number of the problems you mention.
 -=> Yours sincerely, Paul Williams <=-
... "YYYESSS! Wanton destruction, on the next AttiTood!  - JB
--- Terminate 4.00/Pro
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