Battery backup: problem with my APC?

David Brown wrote:
Rod Speed wrote:

David, alot of us have Rod filtered out.

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Ed Light wrote:
David Brown wrote:
Rod Speed wrote:

David, alot of us have Rod filtered out.


I know, and I don't often enter discussions with him. However, he has
some useful things to say if you can avoid triggering the rodbot switch,
as I did for part of my post. Anyway, it's possible that other people
find something of interest in what I wrote, even if Rod disagrees with it.

David Brown wrote
Rod Speed wrote
David Brown wrote
Rod Speed wrote
David Brown wrote
Rod Speed wrote
Ian D wrote
Rod Speed wrote
Ian D wrote
kenk wrote

I was sitting at my desk yesterday during a storm
when there was a split-second power outage. Despite
the fact that my battery shows all 5 lights lit, the
computer died.

Is there a better brand to use than APC? Can the
battery be sub-par even though the test lights say it
is OK? What have others of you chosen?

I would be looking at your PC's power supply. There is
a very brief delay between the loss of power, and the
UPS switchover to battery power.

Not with continuous UPSs, there is no delay at all with those.

Essentially the PC is running off the UPS output all the
time and the only thing that changes with the mains
failure is that the UPS isnt being charged anymore and
runs off the battery instead.

That's correct, and those units are the ones with true sine wave output,

Nope, the type of output is an entirely separate issue.

Both types of UPS generate roughly sine wave outputs when the inverter is active.

Pity he was clearly talking about TRUE sine wave output, which
only a small subset of UPSs produce. And it aint even the
continuous/online UPSs that mostly do produce TRUE sine wave
output.

I don't know exactly what you mean by "TRUE sine wave"

Should be obvious to even someone as stupid as you.

- all UPS's generate a sine wave of sorts when they are active

Wrong, as always. Plenty generate a square wave instead.

You might know about /buying/ and /using/ UPS's, but you don't know much about sine waves, AC/DC conversion,
harmonics, and related technicalities.

Guess which pathetic little prat has just got egg all over its silly little face, yet again ?

I was DESIGNING that stuff before you were even born thanks child.

A square wave (as produced by very low-end UPS's) is just a sine wave with large harmonics.

Thanks for that completely superfluous proof that you have
never ever had a ****ing clue about anything at all, ever.

They are generated completely differently, fool.

And at the high end, good UPS's use PWM switching to produce something closer to a sine wave - even after filtering,
it is still not a "TRUE" sine wave.

Never ever said it was, ****wit.

(i.e., all the time for continuous/online UPS's, or during power
fail for standby devices). The quality of the sine wave varies from
fairly poor (lots of harmonics) to pretty good (few harmonics),
but is /never/ pure.

That last is just plain wrong.

I'll accept that the first part might be wrong - a square wave is a very poor sine wave, rather than just "fairly
poor".

Its nothing like a sine wave, fool.

As I have said, I haven't been looking at such low end devices.

You have always been, and always will be, completely and utterly irrelevant.

What you might or might not have been looking at in spades.

However, if you think that UPS's generate *true* sine waves with no harmonics,

Never ever said anything even remotely resembling anything like that.

It is perfectly possible to generate pure sine waves.

No one bothers with a UPS because there isnt any point in doing that.

I'd love to see the circuit diagrams. I'd also like to know which brands go to great efforts to get closest to a sine
wave -
so that I can avoid them, as it would be a total waste of money.

Didnt say that anyone does, JUST that your stupid pig ignorant
claim that its NEVER possible is just plain pig ignorant and wrong.

If you are restricting discussion only to those UPS's that produce good quality sine waves,

I was JUST commenting on HIS claim about TRUE sine wave output, ****wit.

So I can't talk about UPS's that don't produce mythical "TRUE sine
waves" because a previous poster talked about "TRUE sine wave" UPS's, but /you/ can talk about any UPS's you like?

I was JUST commenting on HIS claim about TRUE SINE WAVE OUTPUT, ****wit.

I'm sure that makes sense to you, somehow.

Never ever could bull**** its way out of a wet paper bag.

then I'll have to take your word for how standby and online UPS
prices compare. Baring the worst of the cheapo devices, the sine quality of any UPS is going to be good enough for
computer
hardware, and is typically better than you get straight from the
mains. Thus it's not a restriction that I've considered.

Completely and utterly irrelevant to the comment I made about his stupid pig ignorant claim about TRUE sine wave
output.

The difference is that with a standby UPS, the inverter is not
active unless the power fails, so the output is just a
filtered version of the input.

Thats an entirely separate matter to TRUE sine wave output.

True - though again, there is no such thing as "TRUE sine wave
output", merely more or less harmonics.

Wrong, as always. True sinewave is NO harmonics.

Correct - a "true sine wave" has no harmonics. No UPS could possibly produce one.

Wrong. Its done for high power oscillators, ****wit.

There is no point in an UPS even trying

Separate matter entirely.

- it makes sense to limit the first few harmonics as much as practically possible, but you get very little gain from
going further than that.

Completely and utterly irrelevant to the comment I made about
his stupid pig ignorant claim about TRUE sine wave output.

Surely you are aware that a "true" sinewave exists only as a
mathematical concept - anything in real life is only going to be an
approximation?

Never ever could bull**** its way out of a wet paper bag.

snip the incoherent rodbot responses

More of you flagrant dishonesty when you get done like a ****ing dinner, as always.

If you are talking about DC supply buses to servers,

Nope, its just as true of desktop PCs.

I've only seen discussions of DC supply buses in the context of server racks, where you have lots of machines
together.

Your problem, as always.

Since desktop PC's are typically spread out, you can't conveniently have a single AC to DC supply for multiple
machines.

No one said anything about supplying multiple machines.

rather than having an AC supply to each, then I think it's a very good idea. It is quite simply idiotic to take a
high voltage AC supply, convert it to low voltage DC for a battery, turn it back to high voltage AC to deliver to a
server's power supply, which then turns it back to a low voltage DC.

It isnt idiotic, its just not as efficient. Many dont give a damn
about the efficiency with a device that isnt taking that much power.

True enough for machines with low power requirements. But the discussion here has moved on to multiple machines

No it hasnt.

- for server racks, the electricity price is often a very big part of the cost.

Like hell it is.

Converting AC to 24V to 48V DC for battery storage, and passing that straight to a server's power supply

Just as true of a desktop's power supply.

It is indeed true of a desktop's power supply - but unless a
significant percentage of users start using UPSs with their desktops,
the economics won't allow anything but AC supplies on desktops.

A significant number do use UPSs on desktops.

would be significantly more efficient in energy use,

Not very significantly, actually.

For people with big installations, even small percentages are significant.

Wrong, as always.

But a rough rule of thumb would be 3-5% energy loss for each high voltage AC to low voltage DC conversion, assuming
top of the range converters. By avoiding the extra conversion to AC after the UPS and before the server supplies,
you'd save up to 10%.

Utterly mangled all over again. And thats not very significant anyway.

and much smaller and cheaper in hardware.

Nope, its actually more expensive, essentially because that approach doesnt sell in the same volume that traditional
UPSs do.

Economics of scale are certainly relevant. But server rack UPS and supply systems are not huge volumes anyway,

No one but you is discussing those.

and the energy savings would be appealing.

Nope. Fart in the bath.

And the hardware itself would be smaller and a
lot cheaper once volumes are of similar magnitudes.

They never ever will be.

Rod Speed wrote:
David Brown wrote
Rod Speed wrote
David Brown wrote
Rod Speed wrote

I know I shouldn't bother responding here, but it's hard to resist...
I'll try not to do it again.

I don't know exactly what you mean by "TRUE sine wave"

Should be obvious to even someone as stupid as you.

- all UPS's generate a sine wave of sorts when they are active

Wrong, as always. Plenty generate a square wave instead.

You might know about /buying/ and /using/ UPS's, but you don't know
much about sine waves, AC/DC conversion, harmonics, and related
technicalities.

Guess which pathetic little prat has just got egg all over its silly
little face, yet again ?


Let me guess - you?

I was DESIGNING that stuff before you were even born thanks child.


Really? You were designing UPS's and inverters before I was born?
Perhaps you were making UPS's for IBM System/360 mainframes - there were
not that many computers around before I was born. So forgive me if I
find that claim just a /touch/ unbelievable.

As I say, you might know something about buying and using UPS's, but you
clearly do not have any idea of the electronics used in an inverter, or
of the mathematics underlying them.

A square wave (as produced by very low-end UPS's) is just a sine
wave with large harmonics.

Thanks for that completely superfluous proof that you have never ever
had a ****ing clue about anything at all, ever.

They are generated completely differently, fool.


/I/ know how they are generated, and how similar and different the
generation is - /you/ do not. The electronics is in principle the same
- it's just you need faster (therefore somewhat more expensive)
switching devices when you want to make something with less harmonics.
It also requires more effort in the controller and software (and
therefore more expense). In addition, different UPSs will have more or
less passive filtering after the inverter - again, the principle is the
same, but some will spend more on the components than others.

And as I said, a square wave is just a sine wave with large harmonics (I
didn't mention how they are generated). Ever heard of Fourier? For
someone who has been designing UPS's for nearly forty years, your
mathematical knowledge is somewhat lacking.

And at the high end, good UPS's use PWM switching to produce
something closer to a sine wave - even after filtering, it is still
not a "TRUE" sine wave.

Never ever said it was, ****wit.


So you now agree that there is no such thing as a "TRUE sine wave"
output from an UPS? It's a pity that you then contradict yourself
/again/ later on.

(i.e., all the time for continuous/online UPS's, or during
power fail for standby devices). The quality of the sine wave
varies from fairly poor (lots of harmonics) to pretty good (few
harmonics), but is /never/ pure.

That last is just plain wrong.

I'll accept that the first part might be wrong - a square wave is a
very poor sine wave, rather than just "fairly poor".

Its nothing like a sine wave, fool.


Here's a couple of links for the mathematically impaired:
http://mathworld.wolfram.com/FourierSeriesSquareWave.html
http://cnx.org/content/m0041/latest/

A square wave is a sine wave with a lot of harmonics. The relevance and
effect of these harmonics will depend on what you do with the output,
but you can't argue with the basic mathematical facts. Well, /you/
apparently /can/ argue with them, but you look a bit silly by doing so.

And for a final clue, let's try to think of an example of a real
application where a square wave is used to replace a sine wave. I know,
how about connecting a square wave output from an UPS to the power
supply of a computer, designed to work with a sine wave mains voltage.
My goodness - it works! It's almost as though the square wave does the
job of an approximate sine wave!

As I have said, I haven't been looking at such low end devices.

You have always been, and always will be, completely and utterly
irrelevant.

What you might or might not have been looking at in spades.

However, if you think that UPS's generate *true* sine waves with no
harmonics,

Never ever said anything even remotely resembling anything like that.


So you now agree that "TRUE sine wave" UPS's, as you have been calling
them, don't generate true sine waves? In fact, you now agree that /all/
UPS's generate approximate sine waves with harmonics?


It is perfectly possible to generate pure sine waves.


Pray, tell me how to do so. If you can produce a /pure/ sine wave, I've
got a perpetual motion machine I'll sell you. Remember, we are talking
about *pure* sine waves, not just something /close/ to a sine wave.

No one bothers with a UPS because there isnt any point in doing that.


At least you've learned that much from my posts.


I'd love to see the circuit diagrams. I'd also like to know which
brands go to great efforts to get closest to a sine wave - so that
I can avoid them, as it would be a total waste of money.

Didnt say that anyone does, JUST that your stupid pig ignorant claim
that its NEVER possible is just plain pig ignorant and wrong.


So you agree that these "TRUE sine wave" UPS's you've been talking about
are mythical? You even agree that close-to-sine UPS's don't exist
because no one wants to pay for them (though it would be possible to
make them).

True - though again, there is no such thing as "TRUE sine wave
output", merely more or less harmonics.

Wrong, as always. True sinewave is NO harmonics.

Correct - a "true sine wave" has no harmonics. No UPS could
possibly produce one.

Wrong. Its done for high power oscillators, ****wit.


No, you do not use a "true sine wave UPS" for a high power oscillator -
you don't necessarily use an UPS at all.

Assuming that by your mangled attempt at a sentence, you meant to say
that a "high power oscillator" is a "true sine wave" generated by an
inverter like an UPS output, then you are still wrong. A "high power
oscillator" will generate it's signal in different ways, depending on
the application. And in particular, it will /never/ generate a /pure/
sine wave. It might have very low harmonics, depending on the needs of
the application, but it will never be pure.

You don't understand the mathematics involved, and you don't understand
the electronics. That's okay - you don't need to know how these devices
work to be able to use them. And just because I /do/ know how to design
UPS's and power supplies of different types and ratings, doesn't mean I
know more about buying or using them than other people. But you
certainly look pretty foolish with all your claims about impossible
devices because you don't understand the principles.

There is no point in an UPS even trying

Separate matter entirely.


Again, you've learned.


Surely you are aware that a "true" sinewave exists only as a
mathematical concept - anything in real life is only going to be an
approximation?

Never ever could bull**** its way out of a wet paper bag.


Well, you've learned /some/ things. Perhaps it's time to re-take the
remedial mathematics classes.

If you are talking about DC supply buses to servers,

Nope, its just as true of desktop PCs.

I've only seen discussions of DC supply buses in the context of
server racks, where you have lots of machines together.

Your problem, as always.

Since desktop PC's are typically spread out, you can't conveniently
have a single AC to DC supply for multiple machines.

No one said anything about supplying multiple machines.


Yes, some talked about supplying multiple machines - /I/ did. Has no
one explained to you the concept of having a discussion involving more
than one person?

rather than having an AC supply to each, then I think it's a
very good idea. It is quite simply idiotic to take a high
voltage AC supply, convert it to low voltage DC for a battery,
turn it back to high voltage AC to deliver to a server's power
supply, which then turns it back to a low voltage DC.

It isnt idiotic, its just not as efficient. Many dont give a damn
about the efficiency with a device that isnt taking that much
power.

True enough for machines with low power requirements. But the
discussion here has moved on to multiple machines

No it hasnt.

- for server racks, the electricity price is often a very big part
of the cost.

Like hell it is.


I forgot - you were /designing/ this stuff before I was born. Go back
to sleep in your rocking chair, old man, and dream of the sixties when
you knew something worth knowing. The rest of us here in 2009 know that
electricity costs are entirely relevant. Here's a link for the
google-impaired:

http://arstechnica.com/business/news/2009/10/datacenter-energy-costs-outpacing-hardware-prices.ars

Converting AC to 24V to 48V DC for battery storage, and passing
that straight to a server's power supply

Just as true of a desktop's power supply.

It is indeed true of a desktop's power supply - but unless a
significant percentage of users start using UPSs with their
desktops, the economics won't allow anything but AC supplies on
desktops.

A significant number do use UPSs on desktops.


Significant as a percentage of desktop users? I'd be surprised if it is
more than a couple of percent. Feel free to provide a link proving me
wrong.

would be significantly more efficient in energy use,

Not very significantly, actually.

For people with big installations, even small percentages are
significant.

Wrong, as always.


Again, I'd recommend those mathematics remedial classes. A small
percentage of a very big number is still a big number, and therefore
significant. Try out some examples with a calculator.

But a rough rule of thumb would be 3-5% energy loss for each high
voltage AC to low voltage DC conversion, assuming top of the range
converters. By avoiding the extra conversion to AC after the UPS
and before the server supplies, you'd save up to 10%.

Utterly mangled all over again. And thats not very significant
anyway.


You are remembering I was talking about big installations?

Are you sure you're not a banker? With claims like that, that 10%
savings on your main running costs being "not significant", you sound a
lot like the half-wits that brought us the current world economic situation.

David Brown wrote
Rod Speed wrote
David Brown wrote
Rod Speed wrote
David Brown wrote
Rod Speed wrote

I know I shouldn't bother responding here,

Yeah, all you're doing is digging that hole you are in deeper and deeper.

You'll be out in china any day now.

but it's hard to resist...

Only for fools like you.

I'll try not to do it again.

Try harder, ****wit child.

I don't know exactly what you mean by "TRUE sine wave"

Should be obvious to even someone as stupid as you.

- all UPS's generate a sine wave of sorts when they are active

Wrong, as always. Plenty generate a square wave instead.

You might know about /buying/ and /using/ UPS's, but you don't know much about sine waves, AC/DC conversion,
harmonics, and related technicalities.

Guess which pathetic little prat has just got egg all over its silly little face, yet again ?

Let me guess - you?

Guess again, in front of a mirror next time.

I was DESIGNING that stuff before you were even born thanks child.

Really?

Yep, really.

You were designing UPS's and inverters before I was born?

I said THAT STUFF, ****wit.

Perhaps you were making UPS's for IBM System/360 mainframes - there were not that many computers around before I was
born.

Didnt say it was for a computer, ****wit.

So forgive me if I find that claim just a /touch/ unbelievable.

You have always been, and always will be, completely and utterly irrelevant.

What you might or might not 'find' in spades.

As I say, you might know something about buying and using UPS's, but you clearly do not have any idea of the
electronics used in an inverter, or of the mathematics underlying them.

Guess which pathetic little prat has just got egg all over its silly little face, yet again ?


I was DESIGNING that stuff before you were even born thanks child.

A square wave (as produced by very low-end UPS's) is just a sine wave with large harmonics.

Thanks for that completely superfluous proof that you have never ever had a ****ing clue about anything at all, ever.

They are generated completely differently, fool.

/I/ know how they are generated,

Then you are a terminal ****wit if you seriously believe that UPSs
that produce a square wave output are producing a sine wave.

and how similar and different the generation is - /you/ do not.

We'll see...

The electronics is in principle the same

Thanks for that completely superfluous proof that you have
never ever had a ****ing clue about anything at all, ever.

- it's just you need faster (therefore somewhat more expensive)
switching devices when you want to make something with less harmonics.

Thanks for that completely superfluous proof that you have
never ever had a ****ing clue about anything at all, ever.

There isnt even ANY 'switching device' with high power sine wave generators, ****wit child.

It also requires more effort in the controller and software (and therefore more expense).

Thanks for that completely superfluous proof that you have
never ever had a ****ing clue about anything at all, ever.

Dont need any software at all, ****wit child.

In addition, different UPSs will have more or less passive filtering after the inverter - again, the principle is the
same, but some will spend more on the components than others.

Thanks for that completely superfluous proof that you have
never ever had a ****ing clue about anything at all, ever.

And as I said, a square wave is just a sine wave with large harmonics

Thanks for that completely superfluous proof that you have
never ever had a ****ing clue about anything at all, ever.

(I didn't mention how they are generated).

And thats where you ****ed up VERY spectacularly indeed.

Ever heard of Fourier?

Before you were even born thanks child.

For someone who has been designing UPS's for nearly forty years, your mathematical knowledge is somewhat lacking.

Having fun thrashing that straw man, ****wit child ?

And at the high end, good UPS's use PWM switching to produce something closer to a sine wave - even after filtering,
it is still not a "TRUE" sine wave.

Never ever said it was, ****wit.

So you now agree that there is no such thing as a "TRUE sine wave" output from an UPS?

Never ever said that either, ****wit child.

It's a pity that you then contradict yourself /again/ later on.

Everyone can see you are lying, again.

(i.e., all the time for continuous/online UPS's, or during
power fail for standby devices). The quality of the sine wave varies from fairly poor (lots of harmonics) to
pretty good (few harmonics), but is /never/ pure.

That last is just plain wrong.

I'll accept that the first part might be wrong - a square wave is a very poor sine wave, rather than just "fairly
poor".

Its nothing like a sine wave, fool.

Here's a couple of links for the mathematically impaired:
http://mathworld.wolfram.com/Fourier...quareWave.html

Doesnt say that a square wave is a sine wave, ****wit child.

http://cnx.org/content/m0041/latest/

Doesnt say that a square wave is a sine wave, ****wit child.

A square wave is a sine wave with a lot of harmonics.

Thats as stupid as claiming that ANY wave is a sine wave with a lot of harmonics, ****wit child.

The relevance and effect of these harmonics will depend on what you do with the output,

And if you generate a sine wave in the first place, there is **** all in the way of harmonics, ****wit child.

but you can't argue with the basic mathematical facts.

You wouldnt know what a real mathematical fact was if it bit you on your lard arse, ****wit child.

Well, /you/ apparently /can/ argue with them, but you look a bit silly by doing so.

Have you the remotest concept of how many are ****ing themselves laughing
at you desperately digging your hole deeper and deeper, ****wit child ?

And for a final clue, let's try to think of an example of a real
application where a square wave is used to replace a sine wave.

Irrelevant to what you get when you generate a sine wave in the first place, ****wit child.

I know, how about connecting a square wave output from an UPS to the power supply of a computer, designed to work with
a sine wave mains voltage. My goodness - it works! It's almost as though the square wave does the job of an
approximate sine wave!

Completely and utterly irrelevant to whether its perfectly possible
to start with a sine wave in the first place, ****wit child.

As I have said, I haven't been looking at such low end devices.

You have always been, and always will be, completely and utterly irrelevant.

What you might or might not have been looking at in spades.

However, if you think that UPS's generate *true* sine waves with no harmonics,

Never ever said anything even remotely resembling anything like that.

So you now agree that "TRUE sine wave" UPS's, as you have been calling them,

Everyone can see for themselves that I never ever said anything like that, ****wit child.

don't generate true sine waves? In fact, you now agree that
/all/ UPS's generate approximate sine waves with harmonics?

Having fun thrashing that straw man, ****wit child ?

It is perfectly possible to generate pure sine waves.

Pray, tell me how to do so.

You start with a sine wave and AMPLIFY it ****wit child.

Done all the time with radio transmitters etc etc etc, ****wit child.

Not just radio transmitters either, ****wit child.

If you can produce a /pure/ sine wave, I've got a perpetual motion machine I'll sell you.

Doesnt defy the laws of physics, ****wit child.

Remember, we are talking about *pure* sine waves,

Like hell we are. No one but YOU used that particular word, you pathetic excuse for a lying bull**** artist.

not just something /close/ to a sine wave.

No one bothers with a UPS because there isnt any point in doing that.

At least you've learned that much from my posts.

Lying, as always. Even someone as stupid as you should be able
to use groups.google and see that I have been saying that LONG
BEFORE YOU EVER SHOWED UP IN USENET, ****wit child.

I'd love to see the circuit diagrams. I'd also like to know which
brands go to great efforts to get closest to a sine wave - so that I can avoid them, as it would be a total waste of
money.

Didnt say that anyone does, JUST that your stupid pig ignorant claim that its NEVER possible is just plain pig
ignorant and wrong.

So you agree that these "TRUE sine wave" UPS's you've been talking about are mythical?

Nope, its perfectly possible to produce one if you want one.

You even agree that close-to-sine UPS's don't exist because no one wants to pay for them (though it would be possible
to make them).

Nope, because they were produced back before it became
much easier to produce square waves instead, ****wit child.

Look up rotary converters sometime, ****wit child.

Those use the same technology that power
stations use to generate the mains, ****wit child.

Corse now you will stupidly try to claim that the mains isnt a sine wave either.

True - though again, there is no such thing as "TRUE sine wave output", merely more or less harmonics.

Wrong, as always. True sinewave is NO harmonics.

Correct - a "true sine wave" has no harmonics. No UPS could possibly produce one.

Wrong. Its done for high power oscillators, ****wit.

No,

Yep.

you do not use a "true sine wave UPS" for a high power oscillator

Never ever said you did, ****wit child.

- you don't necessarily use an UPS at all.

Perfectly possible to generate a high power sine wave, ****wit child.

Assuming that by your mangled attempt at a sentence,

Never ever could bull**** and lie its way out of a wet paper bag.

you meant to say that a "high power oscillator" is a "true sine wave" generated by an inverter like an UPS output,

Stupid assumption.

then you are still wrong.

Having fun thrashing that straw man, ****wit child ?

A "high power oscillator" will generate it's signal in different ways, depending on
the application. And in particular, it will /never/ generate a /pure/ sine wave.

Thanks for that completely superfluous proof that you have
never ever had a ****ing clue about anything at all, ever.

Its purer than the mains its replaces, ****wit child.

It might have very low harmonics, depending on the needs of the application, but it will never be pure.

Its purer than the mains its replaces, ****wit child.

AND you've flagrantly dishonestly slithered off from TRUE to PURE, you lying bull**** artist.

You don't understand the mathematics involved, and you don't understand the electronics.

Everyone can see for themselves that you are lying, ****wit child.

That's okay - you don't need to know how these devices work to be able to use them.

I was DESIGNING that stuff before you were even born thanks ****wit child.

And just because I /do/ know how to design UPS's and power supplies of different types and ratings,

In fact you clearly know **** all about that.

Dont even know what a rotary converter is, ****wit child.

doesn't mean I know more about buying or using them than other people. But you certainly look pretty foolish with all
your claims about impossible devices because you don't understand the principles.

Try telling that to those who have rotary converters, ****wit child.

Dont be TOO surprised then they just laugh in your pathetic little pig ignorant face, AGAIN.

There is no point in an UPS even trying

Separate matter entirely.

Again, you've learned.

Again, you're lying.

Surely you are aware that a "true" sinewave exists only as a mathematical concept - anything in real life is only
going to be an approximation?

Never ever could bull**** its way out of a wet paper bag.

Well, you've learned /some/ things. Perhaps it's time to re-take the remedial mathematics classes.

Nope, time for you to get a HUGE towel for the egg all over your silly little face, ****wit child.

If you are talking about DC supply buses to servers,

Nope, its just as true of desktop PCs.

I've only seen discussions of DC supply buses in the context of server racks, where you have lots of machines
together.

Your problem, as always.

Since desktop PC's are typically spread out, you can't conveniently
have a single AC to DC supply for multiple machines.

No one said anything about supplying multiple machines.

Yes, some talked about supplying multiple machines - /I/ did.

Not till then you didnt, ****wit child. And even all those
voices in your head dont qualify as SOME, ****wit child.

Has no one explained to you the concept of having a discussion involving more than one person?

Never ever could bull**** its way out of a wet paper bag.

rather than having an AC supply to each, then I think it's a
very good idea. It is quite simply idiotic to take a high
voltage AC supply, convert it to low voltage DC for a battery,
turn it back to high voltage AC to deliver to a server's power
supply, which then turns it back to a low voltage DC.

It isnt idiotic, its just not as efficient. Many dont give a damn about the efficiency with a device that isnt
taking that much power.

True enough for machines with low power requirements. But the discussion here has moved on to multiple machines

No it hasnt.

- for server racks, the electricity price is often a very big part of the cost.

Like hell it is.

I forgot - you were /designing/ this stuff before I was born.

Yep.

Go back to sleep in your rocking chair, old man, and dream of the sixties when you knew something worth knowing. The
rest of us here in 2009 know that electricity costs are entirely relevant.

Not when the cost of saving a small amount is higher than what you save, ****wit child.

Converting AC to 24V to 48V DC for battery storage, and passing that straight to a server's power supply

Just as true of a desktop's power supply.

It is indeed true of a desktop's power supply - but unless a significant percentage of users start using UPSs with
their desktops, the economics won't allow anything but AC supplies on desktops.

A significant number do use UPSs on desktops.

Significant as a percentage of desktop users?

Yep.

I'd be surprised if it is more than a couple of percent.

Your problem.

Feel free to provide a link proving me wrong.

Feel free to go and **** yourself, again.

would be significantly more efficient in energy use,

Not very significantly, actually.

For people with big installations, even small percentages are significant.

Wrong, as always.

Again, I'd recommend those mathematics remedial classes.

Again, I'd recommend you go and **** yourself, again, and
retake Bull****ting 101, you clearly slept thru the first time.

A small percentage of a very big number is still a big number, and therefore significant.

What matters is how much it costs to save that, ****wit child.

But a rough rule of thumb would be 3-5% energy loss for each high
voltage AC to low voltage DC conversion, assuming top of the range
converters. By avoiding the extra conversion to AC after the UPS
and before the server supplies, you'd save up to 10%.

Utterly mangled all over again. And thats not very significant anyway.

You are remembering I was talking about big installations?

Are you sure you're not a banker?

No point in asking you if you are a pathetic excuse for a lying bull**** artist.

The answer is obvious.

With claims like that, that 10% savings on your main running costs being "not significant",

Never ever said that either, you silly little pathological liar.

you sound a lot like the half-wits that brought us the current world economic situation.

It didnt happen that way, ****wit child.

David Brown writes:


So you now agree that there is no such thing as a "TRUE sine wave"
output from an UPS? It's a pity that you then contradict yourself
/again/ later on.


Well, I know of one design that I'd call same; but not sure you will.
The best ferro-resonant UPS's are damn close. Of course, such are neither
common or inexpensive.

[But then the line itself is never purely sinusoidal, either; it come
with flaws such as spikes and dropouts...]

The real question is: does the load care if it's not? If all loads are
switchers, usually not at all. Linear wall-warts may. Incandescent lamps
won't have a clue.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher wrote:
David Brown writes:


So you now agree that there is no such thing as a "TRUE sine wave"
output from an UPS? It's a pity that you then contradict yourself
/again/ later on.


Well, I know of one design that I'd call same; but not sure you will.
The best ferro-resonant UPS's are damn close. Of course, such are neither
common or inexpensive.


I've no argument that you can generate very close to sine waves - for
most practical purposes, devices like these are effectively sinusoidal
with no harmonics that you normally need to consider. Every application
has its requirements for how good a sine wave it needs, and you can get
as close as you like (until you are limited by fundamental things like
thermal noise).

I've just been arguing about rodbot's descriptions of UPS outputs as
"true sine wave", and his claims that things like rotary converters and
the mains supply produce /pure/ sine waves with absolutely no harmonics.

[But then the line itself is never purely sinusoidal, either; it come
with flaws such as spikes and dropouts...]

The real question is: does the load care if it's not? If all loads are
switchers, usually not at all. Linear wall-warts may. Incandescent lamps
won't have a clue.

Incandescent lamps /will/ care - they will prefer a square wave, because
there is less variation in the absolute current, and therefore less
variation in heating. This means less thermal and physical stress, and
a longer life for the same power output.

But I agree that the question is if the load cares or not. For many
purposes, a square wave should be better (though DC would be best), but
most devices are specified, optimised and tested with AC (at least
roughly sinusoidal) inputs.

Rod Speed wrote:
snip

Ops, looks like you've blown a fuse again. That can't be good for your
heart at your age. Perhaps you should ask the nurse to up your valium
dosage (or is it lithium?).

David Brown wrote
David Lesher wrote
David Brown wrote

So you now agree that there is no such thing as a "TRUE sine wave" output from an UPS? It's a pity that you then
contradict yourself /again/ later on.

Well, I know of one design that I'd call same; but not sure you will. The best ferro-resonant UPS's are damn close.
Of course, such are neither common or inexpensive.

I've no argument that you can generate very close to sine waves

And that is clearly what the OP was talking
about when he used the term TRUE sine wave.

- for most practical purposes, devices like these are effectively sinusoidal with no harmonics that you normally need
to consider.

What matters is that they are at least as close
to a sine wave as the mains they replace.

Every application has its requirements for how good a sine wave it needs,

What matters with a UPS is that the sine wave is at
least as good harmonics wise as the mains it replaces.

and you can get as close as you like (until you are limited by fundamental things like thermal noise).

You arent necessarily even limited by that.

I've just been arguing about rodbot's descriptions of UPS outputs as "true sine wave",

I never ever used that term myself, you silly little
pathological liar/pathetic excuse for a lying bull**** artist.

and his claims that things like rotary converters and the mains supply produce /pure/ sine waves with absolutely no
harmonics.

Everyone can see for themselves that I never ever said
anything even remotely resembling anything like that, and
in fact never ever use the word PURE sine wave at all, you silly
little pathological liar/pathetic excuse for a lying bull**** artist.

[But then the line itself is never purely sinusoidal, either; it come with flaws such as spikes and dropouts...]

The real question is: does the load care if it's not? If all loads are switchers, usually not at all. Linear
wall-warts may. Incandescent lamps won't have a clue.

Incandescent lamps /will/ care - they will prefer a square wave,

Wrong, as always.

because there is less variation in the absolute current, and therefore less variation in heating.

Mindlessly silly. They dont give a flying red **** about the current being less
than the peak current. In fact that increases the life of the filament, fool.

This means less thermal and physical stress,

Only in your pathetic little pig ignorant fantasyland.

and a longer life for the same power output.

Only in your pathetic little pig ignorant fantasyland.

They in fact prefer a less than sudden current rise, if only
because you dont get as much magnetic field effect with
the coiled filaments etc and less thermal shock with the
initial turn on when the filament cold resistance is lowest.

But I agree that the question is if the load cares or not. For many purposes, a square wave should be better

**** all in fact.

(though DC would be best),

Try sticking that into a switcher and see how well it works.

but most devices are specified, optimised and tested with AC (at least roughly sinusoidal) inputs.

You quite sure you aint one of those rocket scientist silly little
pathological liars/pathetic excuses for a lying bull**** artist ?

Some silly little pathological liar/pathetic excuse for a lying bull**** artist claiming to be
David Brown desperately attempted to bull**** and lie its way out of its predicament
and fooled absolutely no one at all, as always.