> The basic job of a UPS is to replace the power when gets too > low. It may do nothing if it's too high.
My APC and FerrUPS units all will cut over to battery if the power is too low, too high, or out-of-range on frequency. The FerrUPS units also have a mode where they're only doing power conditioning, and will just cut off and not go to battery if the power is bad enough. They are the 'always-on' type of unit. They're large, heavy, hot, noisy, inefficient, and expensive. Of the four 'big guns' I have, only one is in service, on the computer cluster. An APC 2kVA. The rest are all in 'reserve'. That said, except for lightning strikes bad power *should* not damage your electronics, not if it is well-designed to begin with. But a lot of it isn't. I have a story about bad power in Puerto Rico: a bank branch there had a lot of our equipment in the 80's. Power there was unreliable, so the bank had an automatic backup generator. High winds came up from an unusual direction, and started slapping the area's high-voltage power feed lines together. The backup system's contactor fused in the shore power direction, and the bank watched helplessly as the power bounced on and off with the wind, with who knows what kinds of bad inductive and other surges due to this mess. After a few minutes this stopped, and there were curls of smoke coming from all kinds of dead office equipment. Every bit of our gear was running perfectly, as if nothing had happened. They were impressed. We were still using CVT linear power supplies at that time, which sure didn't hurt. It's hard to kill heavy iron and copper. (This is the same technology used by the FerrUPS units.) Also, we designed very conservatively, and tested/abused the crap out of it before entering production. Yes, our gear was on the expensive side, but we (erroneously as it turned out) believed that reliability was a top concern in the banking industry. Turns out cheap PC's is what they wanted, like everybody else. (All hail Windows and the ability to play solitaire at your desk.) That company is gone now. -- Jim _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
