AC line / UPS power switch

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jimandy
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AC line / UPS power switch

Post by jimandy » Wed Oct 05, 2005 10:02 pm

My UPS furnishes power to my computer but the power hungry monitor is plugged into the wall. The idea is that when power fails, the UPS will hold up the CPU longer than if both items are plugged in. This way if I'm not able to get to the system quickly I still have a chance to do an orderly shut down, but only after groveling around on the floor to temporarily plug the monitor into the UPS. I'm looking for a transfer switch...in practical terms, a switch box with two AC cords, one to the UPS and one to the wall outlet, with an outlet for the monitor. The switch would select either wall outlet power or UPS power to drive the monitor. Remote switching would be a bonus but not a necessity. <p>I realize there's no challenge to the circuit, but the world is better off withouth my fooling with AC, so I'm hoping it may be available as a ready made product. Any ideas?
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Chris Smith
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Re: AC line / UPS power switch

Post by Chris Smith » Wed Oct 05, 2005 10:24 pm

You need to learn to shut down windows, blind-folded. <p>Its much easier, if you can shut down all windows programs with out looking at the monitor. <p>It a little hard at first, but not impossible.<p>After the first millon times, it comes easy?

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Re: AC line / UPS power switch

Post by philba » Wed Oct 05, 2005 11:06 pm

windows is easy but, unfortunately, its very hard to shut down applications blind since it's hard to know where you were in the app. I suspect saving that word doc is 10X more important that shutting windows down cleanly.<p>There are manual transfer switches for generators. Maybe you could use one but the cheapest, iirc, is like a couple hundred $$ and still needs to be wired in.<p>Building a manual one should be pretty easy and safe, maybe you could hire an electrician to do it (but don't hire mine) at 30-50/hr you'll still come out ahead. You could even make it automatic but I don't think that's what you wanted.

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Chris Smith
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Re: AC line / UPS power switch

Post by Chris Smith » Wed Oct 05, 2005 11:25 pm

That’s where DOS comes in handy. <p>Windows still uses it and “Alt” “F” “S” still works for me in any of the word processors, as does all of the “Alternate” dos commands in all of the other Windows functions. <p>You just have to learn them, they are all, "Underlined" and have been there since 1985.

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Re: AC line / UPS power switch

Post by jwax » Thu Oct 06, 2005 4:21 am

How long does it take you to shut down? If the monitor is plugged in the UPS, you ought to have a few minutes, no?
If not, get a bigger battery for the UPS.

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Re: AC line / UPS power switch

Post by Newz2000 » Thu Oct 06, 2005 6:38 am

Two things...<p>- set your monitor to shut off after 10 min of inactivity. Then, if you're not at your computer when the power goes off, chances are your monitor isn't using any of the UPS' power and therefore not decreasing it's life.<p>- if your UPS came with a USB or serial cable to hook to your computer, use it. It probably also came with a utility that will notify the computer if its batteries get too low and shut your computer down for you.<p>[ October 06, 2005: Message edited by: Matt Nuzum ]</p>

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Re: AC line / UPS power switch

Post by jimandy » Thu Oct 06, 2005 6:53 am

Well, of course there's more to it. The computer is a Mac (quit laughing) and an even older monitor - no auto shutdown feature available.<p>I've not actually looked at the various loads but I would guess the monitor draws about 3X that of the Mac. Assuming the UPS will hold the computer (by itself) for about 30 minutes then adding the monitor would cut that by a third so I would lose 20 minutes of avaliable shut down time. At my age, getting from the basement TV room to the 3rd floor computer room takes about that long :)
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philba
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Re: AC line / UPS power switch

Post by philba » Thu Oct 06, 2005 9:26 am

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Chris Smith:
You need to learn to shut down windows, blind-folded. <p>Its much easier, if you can shut down all windows programs with out looking at the monitor. <p>It a little hard at first, but not impossible.<p>After the first millon times, it comes easy?<hr></blockquote><p>Sure, shut down windows blind, thats the easy and not very interesting part. Like I said, its the applications that are more important. You want to save your work. Who cares if windows (or a mac) has to do a disk scan on startup but its a disaster if the application file gets lost or trashed. If the app puts up a dialog that you don't see you are lost. "File not saved" springs to mind but there are many others. completely lost if its a modal dialog, which too many apps still have. blind shut down is just not an option here for the important stuff - your data.

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Re: AC line / UPS power switch

Post by Tweetldee » Fri Oct 07, 2005 4:08 am

since your computer is an Apple, and doesn't respond to the Windows shutdown techniques offered by others, I'll offer a low-tech solution. Go to a home improvement center (Lowes, Home Depot, etc), and get an extension cord with an On/Off switch built into the cord. See one at Lowes web site (http://www.lowes.com/lowes/lkn?action=p ... lpage=none). Just hit the switch to turn the monitor off when you walk away, and switch back on when you return.
Piece of cake!!!
Cheers!!
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Re: AC line / UPS power switch

Post by EPA III » Fri Oct 07, 2005 11:09 am

It wouldn't be hard to make such a switch. Buy a couple of extension cords, a three way switch, and a small box to put it in. There are plastic boxes available in hardware stores that would look OK on or under the table. For table top use you can cut any mounting ears off. Be sure to get the three conductor cords with the ground pins (why below). And get some cord clamps that fit the knockouts of the box to provide strain relief on the cords. And a cover plate of course. Oh, and wire nuts. <p>First, cut the extension cords in half and put aside one of the socket ends as it will not be needed. Leaving the plug ends longer may make the wiring fit better. Only the hot lead needs to be switched so the hot from one plug/cord goes to one of the L positions on the switch and the hot from the other plug/cord to the other. The C or common switch position will be the hot for the socket end of the cord that the monitor will be plugged into. The three neutrals and the three ground (bare or green) wires will be tied together in the box. Different cords will require different methods of identifying the hot and neutral wires. If they are colored, the white will be neutral, green will be the safety ground, and the third color (black, red, or ?) will be hot. If not colored, it would be best to use an Ohm meter to trace them from the plug/socket. The round pin is ground, the smaller prong is hot and the wider prong is neutral. <p>It is important to be sure that the cords are not plugged in backwards (hot to neutral and neutral to hot) as that would make a short circuit at the point where the neutrals were spliced and this is the reason for using only three wire cords. A two wire cord could be plugged in backwards with spectacular, but undesirable and perhaps dangerous, results. Besides, once you let the smoke out, it won't work any more. So stick to the three wire cords. <p>Don't be afraid of AC. Use the proper parts. Do use a plastic box. I am talking about a switch box as normally used for wall switches, not a project box from Radio Shack. Plastic will not conduct any accidental shorts to you or other nearby persons or equipment. Wire Nut the connections tight. Twist them till they will not twist any more. No stray wire strands sticking out of the wire nut. Check for errors before plugging it in. An Ohm meter could be used to check for proper function and unwanted shorts before plugging it in. <p>Paul A.
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Re: AC line / UPS power switch

Post by ecerfoglio » Fri Oct 07, 2005 1:22 pm

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> Paul A posted:
It is important to be sure that the cords are not plugged in backwards (hot to neutral and neutral to hot) as that would make a short circuit at the point where the neutrals were spliced and this is the reason for using only three wire cords. A two wire cord could be plugged in backwards with spectacular, but undesirable and perhaps dangerous, results. Besides, once you let the smoke out, it won't work any more. So stick to the three wire cords.
<hr></blockquote><p>Your UPS may have the neutral wires (at the the input and at the output) tied together, but it may not... :) <p>Of course, be shure to follow paul´s safety advice:<p> <blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> Use the proper parts. Do use a plastic box. I am talking about a switch box as normally used for wall switches, not a project box from Radio Shack. Plastic will not conduct any accidental shorts to you or other nearby persons or equipment. Wire Nut the connections tight. Twist them till they will not twist any more. No stray wire strands sticking out of the wire nut. Check for errors before plugging it in. An Ohm meter could be used to check for proper function and unwanted shorts before plugging it in. <hr></blockquote><p>[ October 07, 2005: Message edited by: ecerfoglio ]</p>
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Re: AC line / UPS power switch

Post by Dean Huster » Fri Oct 07, 2005 6:15 pm

If you're going to "roll your own", it's very important that you use what is called a "non-shorting" or "break-before-make" switch. If you don't, you'll temporarily use the UPS to power your entire house backwards through the monitor's circuit, maybe enough to trip the UPS off or blow a UPS fuse and make it totally unnecessary to worry about getting things shut down!<p>Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

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Chris Smith
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Re: AC line / UPS power switch

Post by Chris Smith » Fri Oct 07, 2005 7:11 pm

This doesnt apply to macs, ...but,...All of your WIN applications have DOS commands. <p>Next time you go to shut down a program, look at the underlined letter next to your command. <p>It’s the “alternative command” structure.[DOS] <p> Like I said, it goes back to windows 3.1, and earlier, and it is a crossover from the days of DOS.<p> My word processor, excel, photo suite, etc., and just about every program I use has “underlined” commands to shut down, save, and exit the program blindfolded. <p>When I have a “situation” in most programs, [even a locked up mouse] I do the old time Dos .... “Alt” “F” “S” which gives me the “save” function, followed by “Alt” “F” “X” for close or “exit” followed by the keys ,....“flying windows” “U” “Enter” to shut down the computer. <p>Its not hard to learn.<p>[ October 07, 2005: Message edited by: Chris Smith ]</p>

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philba
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Re: AC line / UPS power switch

Post by philba » Fri Oct 07, 2005 7:48 pm

Yes, there are keyboard accelerators to shut down windows and applications. Not all apps follow the same sequence - some use alt-f-x while some use alf-f-c. Then there is the potential for an unsaved file dialog coming up and they are again not consistent. Closing windows with the win-key+u will send close messages to all the open apps but, prior to exiting, they can chose to put up a dialog, usually a Save dialog box but sometimes others (disconnect springs to mind). So if an app puts up a save dialog and you don't press OK (or S or space or return or what ever the app developer chose) you don't get your data saved. Sure many apps developers use the standard dialogs but many don't. You have to memorize all the accelerators of your applications and know the state of your running applications. Kind of a crapshoot. <p>I believe the mac has a similar set of keys but jimandy is going about this the right way though my solution was just a bigger UPS.<p>On the topic of UPSs, you can get "broken" ones that are almost always broken due to bad batteries. New batteries and you've got a great deal on a UPS.

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Re: AC line / UPS power switch

Post by jimandy » Fri Oct 07, 2005 7:58 pm

Thanks to all, especially Paul, ercofoglia and Dean for the construction notes. <p>Dean, intuition told me that I should use break-before-make, but I wasn't quite sure why. Your explanation was clear. Now to see if I can locate such a switch locally!<p>And to all you folks who may have gotten the wrong idea about Mac, this one is very old, no USB port which, of course, all current models have. And several UPS manufacturers support Mac shut down via USB with supplied drivers.<p>Hmmm, now where did I leave my iPod?<p>[ October 07, 2005: Message edited by: jimandy ]</p>
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