UPS Madness

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Is it just me or does it seem crazy to everyone that a UPS takes, say,
12V from a battery, converts it to 240V AC through some fairly complex
electronics, just to have another set of electronics convert it back to
12V and below. Thoughts?

Cheers,
Michael

Re: UPS Madness



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There are plug-in replacements that replace the PC PS and will run
directly off the battery. So no swap over time, but you pay an extra 10%
in power to top up the battery(deep discharge lead acid)

http://www.mini-box.com/s.nl/sc.8/category.13/.f

Middle flashy one.


Re: UPS Madness



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 It does actually make sense if you consider you need to deal with one
generic black box and interface it with many different types of other
black boxes, and expect all that mess to actually work.

 Back in the early days, you could get a UPS in the shape of an internal
card, which fed power back into the system  via the slots and existing
cables.  But you were dealing with one base, and it was consistent.

 Today, when you're dealing with an assortment of various power rails,
pretty much the only consistent  single power source you have is that
240vac.


 Your argument is certainly stronger when you're talking about laptops
in cars for instance.  Why go from 12v, to 240vac, then 240ac down to
9-19vdc, when you could do that with one step with a DC/DC converter.
 Or in some cases, I've read that some who have 12v input laptops plug
the car's electrical system directly into it.  Too risky IMO, but people
insist on doing it...

Re: UPS Madness


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Converts into many voltages typically.

Also other things (monitors etc) are usually run from the UPS. In a
couple of cases I have seen a small CFL being run from one of the
sockets
to give a bit of light in the room if the power fails at night.

I also leave the ADSL router on the UPS, this way you can use the VOIP
phone, and connect the laptop if there is something urgent you are
doing on the net that just cant wait.

This is the key - its universal and can run just about anything you
plug into it. (within its specified limits).


Finally, UPS only runs when the mains power fails, and usually left on
just long enough to save work and safely shut down.  This isnt likely
to be very often to waste much power due to the inefficiency of the
setup.

OT: Credit where credit is due - Fisher & Paykel


My F&P washing machine was emitting a noise during its emptying cycle
that anyone here would recognise as meaning that the pump bearings were
worn out.

It turns out that the pump can be replaced without any tools whatsoever:
Unplug from the mains, disconnect the pipes from the taps, pull the
waste pipe out of sink and tip the machine on its side (access to the
innards is from underneath). Pull the two power lead spades off the
motor, press a plastic tab to let the motor/pump rotate in its mounting,
and it can be pulled out. Installing the new one is just the reverse.

I wish all repairs were that simple. Nice one F&P.

Sylvia.

Re: OT: Credit where credit is due - Fisher & Paykel


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Sorry, I didn't intend to for that to be a reply.

Sylvia.

Re: OT: Credit where credit is due - Fisher & Paykel


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I discovered that myself a few months back on a friends machine.
Fortunately there wasnt anything wrong with the pumb, except for a
stocking wrapped around the impeller. Removed this, replaced the pump
& it all worked fine.

Re: UPS Madness



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I think it is understandable with a fairly specialised product like a
UPS. However, it seems _really_ crazy when the same principle is
applied to entire households. The increasingly popular use of solar
panels to provide power to a home full of low voltage lighting and
electronics cries out for a standard low voltage DC power rail.

Re: UPS Madness



David Segall wrote:
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When you have a bunch of those awful halogen downlights running at 12 v
4 amps each, you quickly realise its much more efficient to run 240 volt
to each point than install a 12 volt bus.  And how much of that
electronics runs at 3.3,5,6,9,12 or 15 volts ?  Getting a standard for
all that diverse stuff seems unlikely.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
We've slightly trimmed the long signature. Click to see the full one.
Re: UPS Madness



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I will stick with the common lead acid battery voltages thank you. Good
enough standard for me. However, as pointed out, that is all very fine
when everything is at the same point. When it comes to transmitting it
even a hundred metre, cabling losses start to make higher voltages
preferred. hence it is easier to go with the commonly available 240V gear.


Re: UPS Madness


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Cabling losses, as well as the possible need for isolation of power
supplies for certain devices would be issues

There is also the greater fire risk (risk of arcing being maintained
with DC unlike AC) with DC supplies.
(QH transformers are 12v AC and therefore arent a problem.)

Making much more efficient switchmode supplies might be a better
idea.



Re: UPS Madness



:Is it just me or does it seem crazy to everyone that a UPS takes, say,
:12V from a battery, converts it to 240V AC through some fairly complex
:electronics, just to have another set of electronics convert it back to
:12V and below. Thoughts?
:
:Cheers,
:Michael


Not madness at all...

How else do you think you can source 240Vac power when the mains supply normally
used by the PC is not there? I suppose you could replace the UPS with a petrol
genset but other than that what options do you have?

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