> Date: Mon, 28 Jul 2003 21:11:38 +1200 > From: Yuri de Groot <yuri@clear.net.nz> > Subject: [nzlug] UPS fuse (Was: picnic, lightning) > > On Mon, 28 Jul 2003 19:58, cheryl wrote: > > I've had more than one UPS fuse zapped by lightning -- > > better the UPS fuse than every computer in the house! > > So the UPS fuse protected the computers from the lightning? > I'm saving up for an UPS (if my better half lets me). > Are some UPSes better than others in terms of lightning magnitude surges? > > What about those trip switches used for outdoor power tools? > Would they help? > > Yuri The power surges and spikes caused by thunderstorms are not necessarily limited to direct lightning strikes. Water can get into the neighborhood transformer, wet tree branches or bamboo can blow onto the lines shorting out the whole valley, and lightning+water in the transformer can cause it to explode. That's the green flash that lights up the whole valley prior to it going totally black. The power surges are spectacular during these events and its pry worse having transformers up the line malfunctioning during a thunderstorm (lots of spikes and erratic signals) than to have a lightning strike diretly to your home (which would pry just blow your household circuit's fuse and be done with it). Even a surge protector with a resettable fuse (many don't have that anymore!) is better than nothing. If you're short on cash, get one of those first, because you should use them anywhere you're using electronic gear -- your stereo and TV for instance. The deal is, when the voltage goes way too high, the fuse blows, cutting off the circuit entirely before the zap gets to your gear. Most surge protectors just clip out the highs, but don't really do signal conditioning -- they don't protect you from erratic signals or *under* voltages (brownouts) either. A good UPS does a whole lot more. Basically,a UPS keeps a battery charged up all the time, and leeches a nice conditioned power signal off the battery. So it should be providing superior signal conditioning well as a little bit of time to flush your buffers and take down your computer systems gracefully during a power outage. If it gets too big a zap, it blows the fuse where it's plugged into the wall similar to your surge protector -- but the signal conditioner should continue to pull nice clean power off the battery during this event. When you've finally got your UPS you can move the old surge protector to your monitor, and leave the monitor off the UPS, for example. This just means you're drawing less power off the UPS during a power outage, resulting in less downtime on the CPU. And providing *some* protection for your monitor. A good UPS can also aid you in power managment. You can connect the UPS to the CPU via the RS232 port, and program it to tell the computer to shut down nicely when it sees that there's an outage. This is known as APM, Automatic Power Management. The old APMD on linux actually destabilised the kernel on SMP machines, but there are newer methods and utilities out there (another topic!) You can also get additional battery backup to add to your basic UPS if you've got several machines, and have a master CPU running the APMD that can then tell all the other machines to shut down, rather than having a separate UPS for every machine. So there we have incrementally more FAQ fodder. Cheryl ------------------------------------------------------------------- To remove yourself from this list, email nzlug-request@linux.net.nz with "unsubscribe" in the body of the message.
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