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If that is important, then try to find a Best Ferrups UPS. Big old Ferro-resonant transformer has a 2000:1 suppression, and the inverter actually synchronizes itself with the transformer, so as the transformer output decays, the inverter ramps up. They used to show the O-scope of the output side when it kicked online and there is no disturbance. <BR>
<BR>
Ferrups used to be popular with Police and Fire departments, where it was important that equipment not only survive a nearby strike, but not reboot due to a nearby strike. <BR>
<BR>
I don't think they are made new anymore, but ours has lasted 20 years with just replacing batteries every couple of years. They are big, and heavy, but a 1000W unit wouldn't be too bad. <BR>
<BR>
Perhaps a related fact: every computer plugged into that UPS has also lasted forever. I could still power up our 486-DX2 SCO Xenix server if I wanted to. <BR>
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On Tue, 2013-07-09 at 21:06 -0400, Ron Frazier (ALE) wrote:
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<PRE>
Alex Carver <<A HREF="mailto:agcarver+ale@acarver.net">agcarver+ale@acarver.net</A>> wrote:
>On 7/9/2013 13:13, Ron Frazier (ALE) wrote:
>> PS, these ups's only have about 300 joules of surge protection. I've
>> never understood why. I would recommend putting a good media room
>surge
>> protector first in line, with a 2000 - 3000 joule surge protection
>> rating, then the ups.
>
>Because when the voltage exceeds the setpoint it disconnects the load
>from the incoming power and switches to battery. The low surge
>suppression is to handle surges that stay within the switching limits.
>
>
I understand what you're saying, but I'm not totally convinced that's enough. I doubt a 500V 20us transient would trigger a switch over. Even if it did, it takes 10 mS for the switch. The transient probably will have already gone through. But, it could still harm the pc. The response time of a varister in a surge protector is in nanoseconds so it will trap it. But, these are cumulative over time and destroy the surge protector. Since GA has the 2nd highest incidence of lightning in the country, I still like the idea of a big 3000 joule surge protector sitting there.
Sincerely,
Ron
--
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Ron Frazier
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