Re: 1 second UPS
- From: "Dan Hollands" <dhollan3@xxxxxxxxxxxxxxxx>
- Date: Tue, 06 Dec 2005 14:20:28 GMT
"stefanv" <stefan@xxxxxxxxxxxx> wrote in message
news:TZGdnYWjG5qZDQjeRVn_vA@xxxxxxxxxxxxxxx
> Hi, I'm new to this forum, impressed to see there are still a lot of
> people out there who love to play with electronics and do not mind sharing
> some good ideas. So here's my situation;
>
> Dealing with a cabin with a lot of power outages. I have a trace inverter
> system providing DC from 12 volts batteries. I also have a desktop
> computer. When the grid power falls (or comes back) the inverter switches.
> Most often not fast enough and the computer reboots :( I tried a simple
> UPS
> (after the inverter) but it doesn't recognized the modified sine wave from
> the Trace as "clean" power, so it just runs its battery dead after about
> 20 minutes without consider the Trace is there take over.
>
> My search is to find an "UPS" that that will bridge the half a second I
> need for the Trace inverter to kick in. Time being so short, I figure I
> don't need clean power, both voltage and frequency don't need to be
> stable, just something half a second to fool my computer's power supply AC
> is still on.
>
> I was thinking along following lines:
> - feed power to computer using a NO contacts on a DPDT relay 110v AC that
> goes on when AC (Trace) is present.
> - charge (before this relay)through a rectifier a 680uf 200v cap up.
> - create a 20ma 12v power using a rc bridge and a zenner over the cap to
> run a 555 at about 60hz
> - feed this frequency straight to an n-mosfet 200v 15amps switching the
> capacitors charge to the NC contacts of the relay .
> - put a resistor in series with the relay to run it at about 80V (so it
> still goes on at regular 110 supply, but falls faster when the power
> starts going down.)
> - so when the power falls, the relay switches the line AC off and feeds a
> straight square wave at 60 hz for as long as the cap will discharge.
>
> Again this is ugly power, but I only need it for half a second or less.
> When the Trace inverter kicks in the relay will switch back on and regular
> power restored.
>
> Figuring charge in a cap is CV2/2 in watts/sec, a 680 uf cap should hold 4
> watts/sec. A computer power supply being approx 250 watts/hr, this is 0.07
> watts/sec. No I'm not expecting my cap to give me a full minute, that
> would likely make something explode :)
>
> Comments? Better ideas? I like the challenge of doing this without a
> transformer!
>
> Sorry for the long post.
>
> StefanV
>
>
>
>
If you still have the "simple" UPS system that works, why not connect your
big battery in place of the battery in the UPS - assuming the voltages are
compatible.
--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
dhollan3@xxxxxxxxxxxxxxxx
www.QuickScoreRace.com
.
- References:
- 1 second UPS
- From: stefanv
- 1 second UPS
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