[TowerTalk] Whole House Surge Protectors

[Jim McDonald]

Thanks very much for the note, Kevin.  I haven't noticed my unit's being
susceptible to RF (using 1500W output to various antennas).  APC claims
the output is a sine wave, but I don't have a scope, so I haven't
looked at it.  My line voltage doesn't fluctuate more than a volt at
maximum, so I haven't noticed the relay cycling.  I paid only $85 or so
for it, so it was cheap.



Here's the response I just got from tech support at refurbups.com.  BTW,
they sell reconditioned UPS unit.  Maybe users seem to toss the UPS when
the battery goes.  I'm impressed by their technical support.





Hello Jim,

    I have attached a PDF file that will answer your question in regard
to what type of UPS Smart-UPS 700 is. The Smart-UPS line from APC are
all Line Interactive. In the attach file you will find what line
interactive means. Should you not be able to view the PDF file I have
copied and pasted the text below. 



The Line Interactive UPS, illustrated in Figure 2, is the most common
design used for small business, Web, and departmental servers. In this
design, the battery-to-AC power converter (inverter) is always
connected to the output of the UPS. Operating the inverter in reverse
during times when the input AC power is normal provides battery
charging. 



When the input power fails, the transfer switch opens and the power
flows from the battery to the UPS output. With the inverter always on
and connected to the output, this design provides additional filtering
and yields reduced switching transients when compared with the Standby
UPS topology. 



In addition, the Line Interactive design usually incorporates a
tap-changing transformer. This adds voltage regulation by adjusting
transformer taps as the input voltage varies. Voltage regulation is an
important feature when low voltage conditions exist, otherwise the UPS
would transfer to battery and then eventually down the load. This more
frequent battery usage can cause premature battery failure. However,
the inverter can also be designed such that its failure will still
permit power flow from the AC input to the output, which eliminates the
potential of single point failure and effectively provides for two
independent power paths. This topology is inherently very efficient
which leads to high reliability while at the same time providing
superior power protection.



If you have any questions or concerns please feel free to contact me.

 

 

Thank You,

******************************

Eddie Rivera

Technical Support

 

RefurbUPS.com, Inc.

Spook Rock Industrial Park

379 Spook Rock Road

Suffern, NY 10901

 

p: 845-357-6911

f: 845-357-2577

e: erivera at refurbups.com

w: www.refurbups.com



 



 -------- Original Message --------





Jim McDonald wrote:

 

I have an APC Smart-UPS 700 that I bought from RefurbUPS.com. I can't
tell

in the information I have which type of UPS it is. Does anyone know?



Jim N7US

 

 

It's a consumer grade switching UPS with a 500W capacity.

It'll hold half load (250W) for about 14 minutes and full load for about


4.5.



It's designed for PC's and has either a serial or USB connection which 

will allow software running on the PC to catch a signal from the UPS to 

start a graceful shutdown of the PC when the UPS reaches a user defined 

level of discharge.



It is a switching style of UPS and not a 100% inverting style.

In my experience with them they are susceptible to RF and "dirty" line 

power. If the source varies in frequency or voltage by more than about 7


 - 10% the relay will constantly trip in and out.

 

The 100% inverting style of UPS is what you want. They are more 

expensive and probably don't come in VA ratings of less than 1,000.





R. Kevin Stover AC0H