On Sun, Feb 04, 2007 at 07:44:30PM -0500, Kevin Coyner wrote: > On Sun, Feb 04, 2007 at 05:06:20PM -0700, Dave Thayer wrote...... > > On Sun, Feb 04, 2007 at 10:54:30PM +0000, J.A. de Vries wrote: > > > > One other consideration when buying a UPS ... if you plan to back up your > battery powered UPS with a gas, propane or natural gas powered generator > (because you expect power outages to last many hours if not days) then make > sure the UPS you purchase supports an ability to set the voltage sensitivity. > > Your external generator usually takes a good 10 to 15 seconds before the > transfer switch kicks in, making it essential to have a battery powered UPS. > Once the external generator kicks in, the battery powered UPS should stand > down. But the power from the external generator may not be steady, and you're > battery powered UPS will trip in, and then trip out, repeatedly. > > Some of APC's UPS units allow you to set the voltage sensitivity via dip > switches, some of the units allow you to set it via software, and some don't > let you adjust the sensitivity. So if you plan to back up your battery > powered UPS with an external generator, make sure to get a UPS with an > adjustment for voltage sensitivity. >
Or some can run in a dual-mode where unstable power is used to charge the battery and the inverter is used to create clean power for the computer. Some do this as an under-voltage protective measure. It probably costs more. Doug. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
