[ale] OT need 600-1000W power protection for 3 minutes - cheap

Alex Carver agcarver+ale at acarver.net
Tue Jul 9 16:26:44 EDT 2013


On 7/9/2013 12:46, Ron Frazier (ALE) wrote:
> Hi Alex,
>
> Thanks for the BR/BX explanation link.  It looks like the BR series are
> better units.
>
> Would you like to acquire another Smart UPS?  Mine is an SMT-750 (750 VA
> / 500 W) less than 1 year old.  It works great and, as far as I know,
> the batteries are in good shape.  However, the more advanced features
> are beyond my needs and I do need the additional capacity of a BR1500G.
> The current amazon price is $ 272 for this unit.  I'll let mine go for $
> 200, which is a 25% discount.  I'll even deliver it within 30 miles of
> my house (from Cumming, GA, exit 16 on GA 400).

Shipping to Los Angeles wouldn't work out so well. :)


> I probably shouldn't tell you this since I just asked you to buy this
> unit.  But, according to http://www.apcupsd.com/ , this unit will only
> communicate basic data to apcupsd, and will not communicate voltage,
> frequency, etc.

Odd because it works fine with mine.  I get all the data.  In fact I log 
the incoming voltage to track brownouts.

> I was under the impression that computer power supplies were essentially
> (or appear to be) resistive loads.  As an example, my pc is currently
> running at a .98 power factor, almost as many watts as VA.  In any case,
> it psychologically bothers me to have to look at a box for an SMT-750,
> for example, and mentally convert and think, no, that won't power my
> 530W load.  Oh well.

Nope, switching power supplies are very much reactive by the nature of 
their design.  Your power factor is likely not 0.98 because the 
Kill-a-watt has a difficult time with distorted waveforms.  Depending on 
the filtering, your supply likely injects a small amount of harmonics 
back up the power line (a chief complaint by power companies) and that 
interferes with the Kill-a-watt's measurements.  I have two of them, 
they work pretty well on most things and show reasonable numbers for 
items like fans and compressors with AC induction motors (where the 
waveform isn't distorted) but they act weird on any switching power 
supply.  The only good way to do it is with an oscilloscope and a pair 
of probes (voltage and current).

> By the way, for those of you who would like to track the storms in the
> area in case you're worried about power glitches too, I've found a
> couple of good ways to do that.  I'm sure there are others.
>
> Go here and get the Reload Every Firefox plugin and install it (if you
> use Firefox): http://reloadevery.mozdev.org/  Or, you can use the addons
> menu in Firefox.  There are many plugins with similar names though.
>
> This will allow you to automatically refresh a web page on a schedule.

Not to pick on you too much but this is a lot easier without needing 
plugins:
http://radar.weather.gov/radar.php?rid=FFC&product=NCR&overlay=11101111&loop=yes

Click the AutoUpdate button at the bottom of the image and you'll have 
always current radar direct from the source (NOAA, where AccuWeather 
gets its radar data and just gussies it up a bit).  This particular 
radar site covers only north Georgia, with extremities in Alabama and 
Tennessee.  This works on phones, too, since the graphic is an animated 
GIF.  It has a crude zoom feature, too, but it's usually not necessary 
since the scan volumes tend to be large.

Their local forecast page (Atlanta in this case) used to update on its 
own every 15 minutes:

http://forecast.weather.gov/MapClick.php?CityName=Atlanta&state=GA&site=FFC&textField1=33.7629&textField2=-84.4226&e=1

The above radar link came from this page, lower left.


Now, the reason I'm picking on you a little is that this can be done on 
the page (why load an extra plugin for Firefox when the same task can be 
done by the page itself).  But I'm only doing a little picking since my 
main issue is that I have a deep loathing for AccuWeather.  Some number 
of years ago, AccuWeather made a small financial contribution to Senator 
Rick Santorum (Pennsylvania) to support a bill that would force the 
National Weather Service to prevent the public from seeing its data on 
its web page and require the public to pay for service from AccuWeather 
after the public paid for the data via taxes.  The NWS effectively gave 
AccuWeather the finger and kept publishing the data.  The Senate bill 
(S786) died in committee (killed by Senator Bill Nelson of Florida since 
the National Hurricane Center was in AccuWeather's crosshairs, too, and 
that's a no-go for Florida.  I had written to Nelson at the time and got 
a personal reply that effectively read "Don't worry, we've got this".) 
All this happened just as the NWS was starting to really produce an 
online presence that the public could use rather than just a giant 
collection of data files.

To this day I refuse to support AccuWeather and rely entirely on 
NOAA/NWS/NHC for my weather information.  They've steadily made some 
very nice improvements to their page and the data products they provide 
and I like to support that effort.  There's a lot of places in this 
world where the weather data isn't available to the public at large. 
The NWS provides an excellent service and they work hard on it.  I can't 
count how many times I've emailed them about a bug and get a personal 
letter back from a programmer or forecaster.



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