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.
Rod Speed wrote:
> David Brown wrote
>> David Lesher wrote
>>> David Brown <david@westcontrol.removethisbit.com> 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 **** 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.
>
It seems unlikely that you'll ever understand what "true" means in this
context. I know perfectly well what sort of quality sine waves
real-world UPS's can generate, but when you insist on using a precise
technical expression like "true sine wave", even emphasising the "true"
with capitals, you need to be corrected.
>> - 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.
>
In the case of specialised UPS's as mentioned by the previous poster
(you snippet the quotation), the waves should be a lot /better/ than
typical mains supplies.
Mains varies a lot in quality - the voltage can vary quite substantially
from average ratings, you get spikes and droops, phase distortions,
harmonics, and short-term variations from the ideal 50 (or 60) Hz.
>> 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.
>
No, what matters is that it is good enough for the application.
>> 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.
>
Those pesky fundamental physical limitations causing you trouble again?
Yes, you are limited be thermal noise. You can reduce the thermal
noise greatly by cooling, of course, but you can't eliminate it
entirely. And even if you want to run your system in liquid helium,
you've still got quantum effects.
>
>>> 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.
>
There are three issues with changes in current. One is the initial
startup heating and thermal shock from a cold filament. That's the
biggest shock, and the most likely time to blow the bulb. The sine wave
reduces that slightly on average compared to a square wave - but for
each time the light switch is activated, the actual initial inrush
current will depend on where you are in the 50 Hz cycle. And of course,
switch bounce in your average light switch will ensure that each time
you turn the light on, it will be hit by several full voltage blasts.
Then you've got the effect of the I^2R heating. With AC, this will vary
between zero and full effect 100 times per second, leading to changes in
the temperature and thus thermal stresses at this rate - the thermal
mass of the filament is not enough to smooth out these changes. With a
square wave, the absolute current is the same except for brief pause
when the polarity changes. These pauses are much shorter than for a
sinusoidal current, and the current between the pauses is far more
consistent. Thus there is much less thermal stress.
You also mentioned changes in the magnetic field as the current changes.
Yes, this will happen - but the inductance of the filament coil is
very low, and the rate of current change is not /that/ high even in a
square wave output UPS (we are talking real-world supplies here, which
have at least some passive filtering). The magnetic field changes have
two effects in the filament - one is to oppose the current changes
(increasing the time when the square wave is not at its consistent full
current), and the other is physical forces on the filament itself from
its magnetic field. Both of these will be very minor effects.
>> 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.
>
That depends entirely on what you are using. Many power supplies have a
very simple bridge rectifier on the input - they'll be as happy with DC
as AC. Others depend on the AC - an obvious example is if you have a
transformer.
To take proper advantage of a DC system requires a DC supply and
DC-optimised power supplies - clearly a change in the way the
electricity supply works. This would make it impractical for most
purposes - no matter what it's benefits are, it would be incompatible
with existing systems. It would only really be practical for things
like large server setups.
DC Power supplies that work with AC inputs must first rectify the AC to
DC (some will have a transformer before this point, but they are less
common now), before generating the regulated low voltage DC supplies.
If you have a DC input, you can avoid that part - saving costs, size,
and wasted energy. You also avoid all power factor issues.
David Brown wrote
> Rod Speed wrote
>> David Brown wrote
>>> David Lesher wrote
>>>> David Brown <david@westcontrol.removethisbit.com> 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 **** 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.
> It seems unlikely that you'll ever understand what "true" means in this context.
Never ever could bull**** and lie its way out of a wet paper bag.
What he said is clearly what it means, ****wit.
> I know perfectly well what sort of quality sine waves real-world UPS's can generate, but when you insist on using a
> precise technical expression like "true sine wave",
Taint a precise technical expression, ****wit.
> even emphasising the "true" with capitals,
Only did that because you flagrantly dishonestly slithered off to PURE sine waves, ****wit.
> you need to be corrected.
Pity all you ever did was flaunt your complete pig ignorance of what the OP was talking about.
>>> - 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.
> In the case of specialised UPS's as mentioned by the previous poster (you snippet the quotation),
You're lying, as always. I never ever snipped a ****ed thing you silly little pathological liar.
> the waves should be a lot /better/ than typical mains supplies.
Completely and utterly irrelevant to your desperate attempts to bull**** and lie
your way out of your predicament that fools absolutely no one at all, as always.
> Mains varies a lot in quality - the voltage can vary quite substantially from average ratings, you get spikes and
> droops, phase distortions, harmonics, and short-term variations from the ideal 50 (or 60) Hz.
No news to anyone, you pathetic excuse for a lying bull**** artist.
>>> 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.
> No,
Yep.
> what matters is that it is good enough for the application.
Wrong, as always.
>>> 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.
> Those pesky fundamental physical limitations causing you trouble again?
Nope.
> Yes, you are limited be thermal noise.
Nope.
> You can reduce the thermal noise greatly by cooling, of course, but you can't eliminate it entirely.
Dont need to when its a **** in the bath with any practical UPS.
> And even if you want to run your system in liquid helium, you've still got quantum effects.
Never ever could bull**** and lie its way out of a wet paper bag.
>>>> 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.
> There are three issues with changes in current.
Nope.
> One is the initial startup heating and thermal shock from a cold filament. That's the biggest shock, and the most
> likely time to blow the bulb.
And blows a ****ing great hole in your stupid pig ignorant claim that
incandescents last longer with a square wave than a sine wave.
> The sine wave reduces that slightly on average compared to a square wave
So your original claim is just plain wrong.
> - but for each time the light switch is activated, the actual initial inrush current will depend on where you are in
> the 50 Hz cycle.
Still better than with a square wave where it can only be on or off, ****wit.
> And of course, switch bounce in your average light switch will ensure that
> each time you turn the light on, it will be hit by several full voltage blasts.
Still better than with a square wave where it can only be on or off, ****wit.
> Then you've got the effect of the I^2R heating. With AC, this will vary between zero and full effect 100 times per
> second, leading to changes in the temperature
Wrong, as always. The thermal inertia of the filament completely swamps that, ****wit.
> and thus thermal stresses at this rate - the thermal mass of the filament is not enough to smooth out these changes.
Wrong, as always. The light output of an incandescent
isnt even modulated at 100Hz, so the thermal inertia
completely swamps that effect, ****wit.
> With a square wave, the absolute current is the same except for brief pause when the polarity changes. These pauses
> are much shorter than for a sinusoidal current, and the current between the pauses is far more consistent. Thus there
> is much less thermal stress.
How odd that you dont actually get any 100Hz component in the light output, ****wit.
> You also mentioned changes in the magnetic field as the current changes. Yes, this will happen - but the inductance of
> the filament coil is very low,
And the current is very high, particularly when its cold.
> and the rate of current change is not /that/ high
How odd that you can actually see the filament jerk under a microscope, ****wit.
> even in a square wave output UPS (we are talking real-world supplies here, which have at least some passive
> filtering).
Not enough to matter, ****wit.
> The magnetic field changes have two effects in the filament - one is to oppose the current changes (increasing the
> time when the square wave is not at its consistent full current), and the other is physical forces on the filament
> itself from its magnetic field. Both of these will be very minor effects.
How odd that you can actually see the filament jerk under
a microscope, and they almost always fail on turnon, ****wit.
>>> 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.
> That depends entirely on what you are using.
Not with a switcher it wont.
> Many power supplies have a very simple bridge rectifier on the input - they'll be as happy with DC as AC.
Pity about the standby rails.
> Others depend on the AC - an obvious example is if you have a transformer.
<reams of your desperate attempt to bull**** your way out of your predicament
that fools absolutely no one at all, as always, flushed where it belongs>
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?
>
> Thanks
> Ken K
Personally, I've been running a Tripp Lite "Internet Office INTERNET900U"
(900VA, 480 watts) UPS, the past month and a half or so. It features a
whopping 12 AC outlets (6 battery-supported, 6 surge suppression-only);
which, to my knowledge, no other manufacturer can match.
Previously, I'd used an APC "Back-UPS LS 700VA" (BP700UC; 700VA, 410w),
for around 7.5 years. This unit has a "mere" total of seven outlets (4
and 3, respectively). I couldn't plug everything into it, and hence,
also needed a separate power strip/surge suppressor.
Good luck!
--
Cordially,
John Turco <jtur@concentric.net>
Paintings Pain and Pun <http://laughatthepain.blogspot.com>
Re: Battery backup: problem with my APC? 
Linear Mode
