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Reversible UPS

Retro-fit addition to standard Uninterrupted Power Supply which enables it to put power out through its plug.
  (+5, -3)
(+5, -3)
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WARNING: The device described is unsafe and potentially lethal.

The mains connection to the UPS is replaced with a shrouded connector, so that it is impossible to touch the contacts even when it is disengaged.

A relay is added which connects the output of the UPS back to the input cable. This gets controlled by additional remote controlled gear.

Another relay, or set of relays, is added at the mains distribution panel which will isolate the branch connected to the UPS when the mains supply fails, and then send a signal to the relay inside it to change state. When mains supply gets restored, the relay inside the UPS changes over to normal and the power to the branch is restored.

This will enable the UPS to continue supplying power to the computer, and also the lights, fans, etc. inside the room (or house - depends on its capacity) during a power outage.

Right now, in my part of the country, we are in a schedule of power cuts. The mains supply gets cut off for half an hour each evening. If candlelight is insufficient for some task, I get around that by temporarily turning off the mains switch, disconnecting the UPS mains plug and then connecting its output to the mains socket using a piece of cable with plugs at both ends - this idea is to enable all this to happen automatically. Again, let me reiterate that this is NOT SAFE.

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<Yucky boring electronics> The incoming mains powers a high frequency signal generator whose output is impressed across the feed to the UPS (power line carrier communication). This serves as a pilot to indicate presence of mains power. There is also a fast drop-out slow pull-in relay which controls the power to the circuits connected to the same circuit as the UPS.

Inside the UPS, a tuned circuit feeds a tone detector which controls the relay connecting the generated power to the input terminals. As soon as the mains fails, the tone disappears, the connection to the national grid is broken by the relay at the fuse box, and the relay in the UPS operates to power the home.

When power gets restored, the pilot tone comes on. This causes the relay in the UPS to switch over to normal operation, and some time later the relay at the fuse box pulls in, restoring mains power to the UPS and surrounding places. </Ybe>

The danger is that there is no easy way to cut off power at the mains, in case of somebody getting accidentally fried.

neelandan, Sep 29 2008

Whole house UPS http://www.nooutage...hups-advantages.htm
[phoenix, Sep 29 2008]

[link]






       If the circuit requires more current than the UPS provides, it might start a fire. Nice on a cold winter night, if you can extinguish it in time.
Amos Kito, Sep 29 2008
  

       extremely dangerous and unfit for use in a residence. (+)
Voice, Sep 29 2008
  

       Very interesting (+).
MisterQED, Sep 29 2008
  

       Wouldn't the UPS be trying to power the whole national grid in these circumstances?
hippo, Sep 29 2008
  

       Yes. So a relay at the fuse box isolates it from the national grid.
neelandan, Sep 29 2008
  

       // a relay .... isolates it //   

       In which case ...   

       Since you're going to be installing a pair of contactors in circuit with your mains incomer and distribution system to achieve this, along with a bit of hard-wired logic to manage the connection/exclusion sequence, you might as well just buy a realy chunky UPS and patch it in between the line fuse and the consumer unit; then put a manual changeover switch on the input to the UPS so that you can recharge it from a generator if the grid doesn't come back up.   

       Sorry, but this is Baked and Widely Known To Exist. [hinted-at-for-removal].
8th of 7, Sep 29 2008
  

       There's no real solution if you insist on the UPS being physically in your computer room. The realistic thing to do is find out which wiring loop (controlled by one fuse) has the best outlets and lighting for emergency use, and hook up the UPS between them. However, since you'd need a UPS that can handle the draw of that entire loop and there's very little chance a PC UPS is gonna be able to do that then you're left with two non-explosive choices:
a) get a real UPS and hook it up to aforesaid wiring loop or the whole house (give or take electrical stove or A/C), or... b) go get some fibre-optics, a couple LED's and a little transformer, get your powerdrill out and make your own "emergency lighting" system for the computer room and the ones adjacent, running off your PC UPS.
FlyingToaster, Sep 29 2008
  

       1&1/7: Yucky boring electronic details added. Your hint can be carried out by placing your mouse pointer on the right of the two links below your annotation, and tapping on the mouse button.
neelandan, Sep 29 2008
  

       Delayed Outage Watt-Networking System?   

       Or something similar?
theleopard, Sep 29 2008
  

       [n] your system won't work. A PC UPS can't support the potential draw of a normal household. (Again) your options (which btw, require less work than your proposal) are:
a) Get a UPS for the whole house (installed on the mains before the fusebox, or
b) Get a UPS for the whole house minus stove/AC which are often tapped before the main fusebox, or
c) Get a UPS for one power loop (spliced into the fusebox) or
d) create a new emergency-lighting system using your PC-UPS.
What you *don't* want to do is what you suggest, since a failure of that system might not only burn your house down but could electrocute people from the power-company working on the mains your house is connected to.
FlyingToaster, Sep 29 2008
  

       [marked-for-tagline] WARNING: The device described is unsafe and potentially lethal.
BunsenHoneydew, Oct 02 2008
  

       In most places in the US, a device that does this is illegal without the automatic cutoff at the breaker box. Thus, the last thing you want is one that can be moved around easily. As has been pointed out above, if you're going to install cutoff you might as well permanently install the UPS. Which is either going to involve a lot of batteries or a small battery and a fossil fuel generator, most likely.
MechE, Oct 03 2008
  
      
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