# continuous online dual conversion UPS

Discussion in 'Electrical Engineering' started by [email protected], Mar 3, 2009.

1. ### Guest

While reading some technical descriptions of specific UPS models, including
user manuals, I have found that many describe a low voltage level at which
they "switch" or "transfer" from utility power to battery power.

For this kind of UPS, where even the utility power is always converted to DC
and then back again to AC (inverter), why can't they do a combined capability
in a low voltage situation in order to extend the battery as long as possible?

One type of low voltage scenario I have seen happen a few times is when the
voltage is dropped to HALF the nominal voltage. The primary (pardon the pun)
cause I understand for this is when a delta-wye transformer loses one phase
on the primary side. Suppose phase B is lost. Phases A and C are still live.
The delta primary A-C winding still has full voltage. However, the A-B and
the B-C windings are in series fed from phases A and C. Given an equal load
on the secondaries for A-B and B-C, this should divide the voltage in half
for each. So 120/240 becomes 60/120, and 208Y/120 becomes 104Y/60.

At half the voltage, a UPS would want to draw twice the current to sustain the
connected loads (maybe more if the circuitry operates at less efficiency in
this condition). And that may be too much current. At some low voltage the
current will exceed what the input should operate at.

So, when this low voltage condition exists, why not just go ahead and operate
the AC to DC conversion at a level right at the current limit, and obtain the
remaining power from the battery? By drawing less from the battery, and the
most that is still safe from what can be gotten from the low utility voltage,
the battery can last longer than it otherwise would. Is it too complex or
costly to make an AC to DC conversion (basically a power supply) section that
would operate on these lower voltages? Or is it too complex or costly to make
one that can limit its operation to a specific current level?

2. ### Guest

|
| wrote:
|>
|> While reading some technical descriptions of specific UPS models, including
|> user manuals, I have found that many describe a low voltage level at which
|> they "switch" or "transfer" from utility power to battery power.
|>
|> For this kind of UPS, where even the utility power is always converted to DC
|> and then back again to AC (inverter), why can't they do a combined capability
|> in a low voltage situation in order to extend the battery as long as possible?
|>
|> One type of low voltage scenario I have seen happen a few times is when the
|> voltage is dropped to HALF the nominal voltage. The primary (pardon the pun)
|> cause I understand for this is when a delta-wye transformer loses one phase
|> on the primary side. Suppose phase B is lost. Phases A and C are still live.
|> The delta primary A-C winding still has full voltage. However, the A-B and
|> the B-C windings are in series fed from phases A and C. Given an equal load
|> on the secondaries for A-B and B-C, this should divide the voltage in half
|> for each. So 120/240 becomes 60/120, and 208Y/120 becomes 104Y/60.
|>
|> At half the voltage, a UPS would want to draw twice the current to sustain the
|> connected loads (maybe more if the circuitry operates at less efficiency in
|> this condition). And that may be too much current. At some low voltage the
|> current will exceed what the input should operate at.
|>
|> So, when this low voltage condition exists, why not just go ahead and operate
|> the AC to DC conversion at a level right at the current limit, and obtain the
|> remaining power from the battery? By drawing less from the battery, and the
|> most that is still safe from what can be gotten from the low utility voltage,
|> the battery can last longer than it otherwise would. Is it too complex or
|> costly to make an AC to DC conversion (basically a power supply) section that
|> would operate on these lower voltages? Or is it too complex or costly to make
|> one that can limit its operation to a specific current level?
|
|
| Another idiot idea from Phil. Why would you want the added
| complexity for a half assed idea that would make the unit more likely to
| fail? Why do you think CVTs are used on some systems? On second
| thought, do you ever think things through before starting one of your

You can't read. But then, you seem to have had this trouble for the past few
years. I would speculate it has been a lifelong condition for you. I simply
do not know if this was something that happened early in your life or just a
few years ago, since I have not seen your writings prior to a few years ago.

The unit is more likely to fail if you let the battery carry the full load,
instead of letting the battery share the load with what power it can get from
the available mains voltage.

And I did not specify a particular design. If you want to discuss the failure
modes of a particular design, then go ahead and spell out what that design is
and we can discuss how and why it might fail (break down). If you do that, do
keep in mind that it was your design, not mine.

If you want to assert a belief that no design is possible to do this, then by
all means assert that. That will, of course, open you to the criticism that
you are unable to come up with all possible designs, and MAY have missed one
that would work well. You could defend against that by spelling out all the

3. ### Guest

| I have no problem reading and identifying moronic concepts.

You have no skill in reading electrical enginering or technology. All the
rest is fiction in your mind.

|> The unit is more likely to fail if you let the battery carry the full load,
|> instead of letting the battery share the load with what power it can get from
|> the available mains voltage.
|
|
| Then the battery is too small, or too old. An overly complex design
| isn't the answer to crappy maintenance.

It doesn't matter what the battery size is, small, medium, or large. If you
power the loads entirely from the battery, it will last a shorter time than
if you power the loads half from the battery and have from the mains.

|> And I did not specify a particular design. If you want to discuss the failure
|> modes of a particular design, then go ahead and spell out what that design is
|> and we can discuss how and why it might fail (break down). If you do that, do
|> keep in mind that it was your design, not mine.
|
|
| You didn't specify a design because you can't. It is another of your
| ignorant 'Gee Whiz!!!' ideas that won't work.

Whether I can or not is irrelevant. I didn't try. So it doesn't matter.
What I did was ask about the concept. You suggested it would fail, so you
You said so.

|> If you want to assert a belief that no design is possible to do this, then by
|> all means assert that. That will, of course, open you to the criticism that
|> you are unable to come up with all possible designs, and MAY have missed one
|> that would work well. You could defend against that by spelling out all the
|
|
| Its your stupid idea so its up to you to show us a design that will
| work while meeting all safety requirements, including isolation form the
| faulty power line, while continuing to draw power from it. How are you
| going to match the distorted waveform in real time, and adjust the
| voltage to what you need? Like I said in my first reply, "Why do you
| think CVTs are used on some systems?" but you didn't answer, because you
| don't know, or because it would prove this stupid scheme is worthless.

I came up with the basic concept. I didn't say I have a design that would
work. I didn't say there has to be a design that worked. I ASKED ABOUT THE
CONCEPT. YOU are convinced it cannot work, but YOU are completely unable to
say why it would not work. Sounds to me like you are unwilling to disclose
your design failure or whatever logic you came up with that suggests all the
possible designs would fail. So what's left is your baseless assertion.

4. ### Guest

|
| wrote:
|>
|>
|> | I have no problem reading and identifying moronic concepts.
|>
|> You have no skill in reading electrical enginering or technology. All the
|> rest is fiction in your mind.
|
|
| Yawn. Another lame attempt to slur my name. The 'fiction' is that
| you believe the crap you dream up will work. What have you ever done in
| the real world? My design ideas are in space, aboard the ISS, used to
| track everything launched by NASA, the ESA, and by NOAA to track and
| control their LEO Weather Satellites. I also came up with the idea of
| uplinking a subcarrier channel to a C-band satellite from a different
| site than the main carrier. This was for United Video's microwave
| division for their EPG service on the WGN feed. It eliminated two
| leased phone lines from Salt Lake City where the mainframe computers
| were, to the WGN uplink in Chicago. It provided a more reliable service,
| and the savings of over \$15,000 a month for the company I worked for.

You could have made a lot more contributions to the world if you had the
ability to read English and did not have the attitude of distorting what
people say so you gain the ability to make assertions that are really false
and lets you blame it on them. I'm not going to play your penis length
game. There's no way to verify the truth or significance in anything you
say.

Maybe you really did those things in the past and maybe they will work fine.
But your brain is certainly not keeping up. Damaged?

|> |> The unit is more likely to fail if you let the battery carry the full load,
|> |> instead of letting the battery share the load with what power it can get from
|> |> the available mains voltage.
|> |
|> |
|> | Then the battery is too small, or too old. An overly complex design
|> | isn't the answer to crappy maintenance.
|>
|> It doesn't matter what the battery size is, small, medium, or large. If you
|> power the loads entirely from the battery, it will last a shorter time than
|> if you power the loads half from the battery and have from the mains.
|
|
| If the battery size doesn't matter, then use eight AAA cells.

You are a complete lunkhead if you haven't figured out by now that this is
about comparing the SAME SIZE BATTERY with 2 different wiring schemes, one
where the battery carries the full load, and the other where the battery
carries half the load. If YOU can't figure out the basic concept that when
a battery only carries half the load, it runs longer, then I guess I need
notify NASA, ESA, NOAA, that they might some flawed engineering running and
their missions are at risk of things like premature battery failure. That
is, if you aren't lying.

|> |> And I did not specify a particular design. If you want to discuss the failure
|> |> modes of a particular design, then go ahead and spell out what that design is
|> |> and we can discuss how and why it might fail (break down). If you do that, do
|> |> keep in mind that it was your design, not mine.
|> |
|> |
|> | You didn't specify a design because you can't. It is another of your
|> | ignorant 'Gee Whiz!!!' ideas that won't work.
|>
|> Whether I can or not is irrelevant. I didn't try. So it doesn't matter.
|> What I did was ask about the concept. You suggested it would fail, so you
|> You said so.
|
|
| I didn't try to design anything, because your concept is so flawed.
| That is something you never see in the stupid crap you dream up. Your
| stupid idea would be dropped in ten seconds in a design review, and you
| would be told to clean out your desk.

You think that the concept of running a battery at half load to extend its
run time, relative to the same size battery running full load, is a flawed
concept?

Now I have to say it ... what an utter moron.

5. ### Guest

| wrote:
|>
| What we used to do to power 2 way radio systems for police and fire
| systems is power the systems from batteries full time with a smart
| charger that is big enough and well filtered enough to power both the
| loads and charge the batteries. No switchover time, will charge the
| batteries even in brownout conditions.

Lots of AC to DC converters, chargers, and power supplies, can work on a
wide range of voltage coming in. If it is rated 100-240 volts, as most
computer power supplies are, then connecting it to a 240 volt circuit
gives you a LOT of deep brownout range. Just be sure the circuit has
amperage capacity for the low voltage scenerio.

The question I have is whether it is something UPS makers can do. Based on
ratings I have seen, they design for a limited amoutn of brownout. The ones
in the Minuteman Endeavor series I was looking at had a low voltage cutout
at 86 volts for the 120 volt models. That's not as much voltage range as
computer power supplies. Maybe they could do better. Maybe it will cost
\$10 more and ruin their market advantage for the average consumer.

6. ### Guest

|
| wrote:
|>
|> |
|> | wrote:
|> |>
|> |>
|> |> | I have no problem reading and identifying moronic concepts.
|> |>
|> |> You have no skill in reading electrical enginering or technology. All the
|> |> rest is fiction in your mind.
|> |
|> |
|> | Yawn. Another lame attempt to slur my name. The 'fiction' is that
|> | you believe the crap you dream up will work. What have you ever done in
|> | the real world? My design ideas are in space, aboard the ISS, used to
|> | track everything launched by NASA, the ESA, and by NOAA to track and
|> | control their LEO Weather Satellites. I also came up with the idea of
|> | uplinking a subcarrier channel to a C-band satellite from a different
|> | site than the main carrier. This was for United Video's microwave
|> | division for their EPG service on the WGN feed. It eliminated two
|> | leased phone lines from Salt Lake City where the mainframe computers
|> | were, to the WGN uplink in Chicago. It provided a more reliable service,
|> | and the savings of over \$15,000 a month for the company I worked for.
|>
|> You could have made a lot more contributions to the world if you had the
|> ability to read English and did not have the attitude of distorting what
|> people say so you gain the ability to make assertions that are really false
|> and lets you blame it on them. I'm not going to play your penis length
|> game. There's no way to verify the truth or significance in anything you
|> say.
|>
|> Maybe you really did those things in the past and maybe they will work fine.
|> But your brain is certainly not keeping up. Damaged?
|
|
| Keep throwing your hissy fits, Phil. You can't design anything, and
| continue to show the world what a fool you are.

What did you think I designed?

You're the one that doesn't understand how to extend the life of a battery

|> |> |> The unit is more likely to fail if you let the battery carry the full load,
|> |> |> instead of letting the battery share the load with what power it can get from
|> |> |> the available mains voltage.
|> |> |
|> |> |
|> |> | Then the battery is too small, or too old. An overly complex design
|> |> | isn't the answer to crappy maintenance.
|> |>
|> |> It doesn't matter what the battery size is, small, medium, or large. If you
|> |> power the loads entirely from the battery, it will last a shorter time than
|> |> if you power the loads half from the battery and have from the mains.
|> |
|> |
|> | If the battery size doesn't matter, then use eight AAA cells.
|>
|> You are a complete lunkhead if you haven't figured out by now that this is
|> about comparing the SAME SIZE BATTERY with 2 different wiring schemes, one
|> where the battery carries the full load, and the other where the battery
|> carries half the load. If YOU can't figure out the basic concept that when
|> a battery only carries half the load, it runs longer, then I guess I need
|> notify NASA, ESA, NOAA, that they might some flawed engineering running and
|> their missions are at risk of things like premature battery failure. That
|> is, if you aren't lying.
|
|
| That wasn't what you stated. You said the battery size doesn't
| matter, not how the same size battery was used. You claim I can't read,
| yet you can't even read what you wrote.

And the statement is correct. The size does not matter for the principle
to apply. If you understood what the principle is, maybe then you would
understand that it works no matter what size of battery is involved. If
the load on the battery is reduced, it will last longer.

|> |> |> And I did not specify a particular design. If you want to discuss the failure
|> |> |> modes of a particular design, then go ahead and spell out what that design is
|> |> |> and we can discuss how and why it might fail (break down). If you do that, do
|> |> |> keep in mind that it was your design, not mine.
|> |> |
|> |> |
|> |> | You didn't specify a design because you can't. It is another of your
|> |> | ignorant 'Gee Whiz!!!' ideas that won't work.
|> |>
|> |> Whether I can or not is irrelevant. I didn't try. So it doesn't matter.
|> |> What I did was ask about the concept. You suggested it would fail, so you
|> |> are the one that has a specific design in mind. YOUR DESIGN is a failure.
|> |> You said so.
|> |
|> |
|> | I didn't try to design anything, because your concept is so flawed.
|> | That is something you never see in the stupid crap you dream up. Your
|> | stupid idea would be dropped in ten seconds in a design review, and you
|> | would be told to clean out your desk.
|>
|> You think that the concept of running a battery at half load to extend its
|> run time, relative to the same size battery running full load, is a flawed
|> concept?
|
| I never said that. I stated that a properly sized battery was need
| but as usual, you can't read and comprehend anything. Properly sized
| means that it has a reasonable reserve, and in exchange will give you a
| longer run time, if needed before the power is restored, or a backup
| generator comes on line. A larger battery is more reliable than the
| Rube Goldberg crap you come up with. You need to learn the KISS method
| if you want things to keep working.

Whatever size you have, if the load is reduced, the battery runs longer.
If you do ever need it to run that long, maybe you got a too large battery.

The real world involves UPSes that in most cases have limitations on the
battery size, while the market wants longer run times. The "proper sizing"
is just not something that is easily doable. That's a concept that applies
when setting up large scale batteries with separate chargers and inverters.
And I've done that for two mainframe data centers.

|> Now I have to say it ... what an utter moron.
|
|
| We know you're a moron.

7. ### Guest

|
| wrote:
|>
|> |
|> | wrote:
|> |>
|> |> |
|> |> | wrote:
|> |> |>
|> |> |>
|> |> |> | I have no problem reading and identifying moronic concepts.
|> |> |>
|> |> |> You have no skill in reading electrical enginering or technology. All the
|> |> |> rest is fiction in your mind.
|> |> |
|> |> |
|> |> | Yawn. Another lame attempt to slur my name. The 'fiction' is that
|> |> | you believe the crap you dream up will work. What have you ever done in
|> |> | the real world? My design ideas are in space, aboard the ISS, used to
|> |> | track everything launched by NASA, the ESA, and by NOAA to track and
|> |> | control their LEO Weather Satellites. I also came up with the idea of
|> |> | uplinking a subcarrier channel to a C-band satellite from a different
|> |> | site than the main carrier. This was for United Video's microwave
|> |> | division for their EPG service on the WGN feed. It eliminated two
|> |> | leased phone lines from Salt Lake City where the mainframe computers
|> |> | were, to the WGN uplink in Chicago. It provided a more reliable service,
|> |> | and the savings of over \$15,000 a month for the company I worked for.
|> |>
|> |> You could have made a lot more contributions to the world if you had the
|> |> ability to read English and did not have the attitude of distorting what
|> |> people say so you gain the ability to make assertions that are really false
|> |> and lets you blame it on them. I'm not going to play your penis length
|> |> game. There's no way to verify the truth or significance in anything you
|> |> say.
|> |>
|> |> Maybe you really did those things in the past and maybe they will work fine.
|> |> But your brain is certainly not keeping up. Damaged?
|> |
|> |
|> | Keep throwing your hissy fits, Phil. You can't design anything, and
|> | continue to show the world what a fool you are.
|>
|> What did you think I designed?
|
|
| Absolutely nothing that has ever worked.

With respect to this thread, I did not design anything. So I guess you
have actually made a statement that would evaluate as true.

|> You're the one that doesn't understand how to extend the life of a battery
|
|
| Bullshit. I stated several times in this thread about choosing the
| proper capacity which isn't using them at 99% of their rated capacity.
| I am a firm believer in properly de-rating a design so it is never
| stressed beyond reason, but your blind ignorance forces you to ignore
| what anyone tells you.

When have you ever designed a UPS that is in commercial production?
Guess what. They don't do this. They can't. The reason they can't
is because needs vary so widely. The best they can do is make a
range of designs and let the buyer select what will most closely fit
their needs.

| As you can see a few lines down I stated : Then the battery is too
| small, or too old. An overly complex design isn't the answer to crappy
| maintenance. then you tell me I would chose too small of a battery,
| once again proving you have zero comprehension of anything you read.

What I stated is a fact that follows across all sizes, ratings, and ages
of common batteries. Your statements don't even address it at all. You
have no comprehension of what is being discussed. As I have said before
to realize what people are talking about.

|> Whatever size you have, if the load is reduced, the battery runs longer.
|> If you do ever need it to run that long, maybe you got a too large battery.
|
|
| Sigh. You can't even tell there is anything outside the box, can
| you?

Specify what box you are referring to.

|> The real world involves UPSes that in most cases have limitations on the
|> battery size, while the market wants longer run times. The "proper sizing"
|> is just not something that is easily doable. That's a concept that applies
|> when setting up large scale batteries with separate chargers and inverters.
|> And I've done that for two mainframe data centers.
|
|
| Whoopee. Two whole jobs. Get back to me when you know what your
| trying to do. y starting with say 50% extra batter capacity, they will
| last longer, and still be usable as they start to degrade, as well as
| handle surges if something has to be restarted while the system is
| running on the UPS.

I never said anything about "50% extra batter capacity". Your failure to
understand what you read is in play, again.

I referred to reducing the load on the battery by 50%. That means a battery
with linear runtime characteristics (a hypothetical battery that merely
approximates real life battery performance) would run twice as long. That
isn't "50% extra batter capacity". It *IS* effective a 100% extra UNIT
capacity when considering one unit with the feature I suggested against a
unit without, when they each have the same battery.

Of course real batteries are non-linear with respect to runtime, and vary
with other factors like aging, wear (number of cycles), temperature, and
rate of usage (the power drawn from it).

|> |> Now I have to say it ... what an utter moron.
|> |
|> |
|> | We know you're a moron.
|>
|
|
| Phil, you are a world class ignoramus who lives to put layer after
| layer of cheap lipstick on the pigs you dream up. Your other hobby is
| separating fly shit from pepper, under a broken microscope.
|
| Keep showing everyone what a fool you are. Some people enjoy watching
| you go down for the third time, so they can toss you a concrete life
| preserver.
|
| No one expect you to ever learn anything or to admit what a fool you
| really are. You make Roy look smart, by comparison.

I'm only showing what a fool you are.

8. ### Guest

|> their needs.
|>
|> | As you can see a few lines down I stated : Then the battery is too
|> | small, or too old. An overly complex design isn't the answer to crappy
|> | maintenance. then you tell me I would chose too small of a battery,
|> | once again proving you have zero comprehension of anything you read.
|>
|> What I stated is a fact that follows across all sizes, ratings, and ages
|> of common batteries. Your statements don't even address it at all. You
|> have no comprehension of what is being discussed. As I have said before
|> in other past threads, your difficulty is comprehending English well enough
|> to realize what people are talking about.
|>
|> |> Whatever size you have, if the load is reduced, the battery runs longer.
|> |> If you do ever need it to run that long, maybe you got a too large battery.
|> |
|> |
|> | Sigh. You can't even tell there is anything outside the box, can
|> | you?
|>
|> Specify what box you are referring to.
|
|
| You are so stupid that you hav enver hear of "Thinking outside the
| box"?

You are quite creative. You have that going for you.

I know about "Thinking outside the box". But you didn't specify that
box as the one you were referring to before I asked you to.

|> |> The real world involves UPSes that in most cases have limitations on the
|> |> battery size, while the market wants longer run times. The "proper sizing"
|> |> is just not something that is easily doable. That's a concept that applies
|> |> when setting up large scale batteries with separate chargers and inverters.
|> |> And I've done that for two mainframe data centers.
|> |
|> |
|> | Whoopee. Two whole jobs. Get back to me when you know what your
|> | trying to do. y starting with say 50% extra batter capacity, they will
|> | last longer, and still be usable as they start to degrade, as well as
|> | handle surges if something has to be restarted while the system is
|> | running on the UPS.
|>
|> I never said anything about "50% extra batter capacity". Your failure to
|> understand what you read is in play, again.
|
|
| No, I SAID THAT I WOULD USE A BATTERY BANK 50% MORE THEN THE MINIMUM
| TO EXTEND ITS LIFE.

With some UPSes you can do that. With others, you can't.

I *AM* talking about a redesign (without yet doing that redesign) of the
charging (AC to DC) component of the UPS so that it will get whatever
power it can get from a deep brownout condition, and use that to charge
the battery or supplement the use of the battery.

It is PLAUSIBLE to do this because switch mode power supplies, which are
devices that convert AC to DC at one or more DC output voltages, can
readily and easily be made to operate over a voltage range greater than
2:1. Most computer power supplies now do 100 to 240 volts AC continuous,
without needing one of those "115/230" switches. Almost all my wall
warts do this, too. If it can be done for 100 to 240, it could also be
done for 50 to 120, and thus be within the range for the class of deep
brownout I have seen about half the time. Or a 240 volt class UPS can
be left at the 100 to 240 volt range. What will need to be done to
accomodate this is to be sure the current at the low voltage can be
handled, or be restricted/limited.

So really, I don't even need to design this. It has already been done.

|> I referred to reducing the load on the battery by 50%. That means a battery
|> with linear runtime characteristics (a hypothetical battery that merely
|> approximates real life battery performance) would run twice as long. That
|> isn't "50% extra batter capacity". It *IS* effective a 100% extra UNIT
|> capacity when considering one unit with the feature I suggested against a
|> unit without, when they each have the same battery.
|>
|> Of course real batteries are non-linear with respect to runtime, and vary
|> with other factors like aging, wear (number of cycles), temperature, and
|> rate of usage (the power drawn from it).
|>
|> |> |> Now I have to say it ... what an utter moron.
|> |> |
|> |> |
|> |> | We know you're a moron.
|> |>
|> |> You've proven your ignorance.
|> |
|> |
|> | Phil, you are a world class ignoramus who lives to put layer after
|> | layer of cheap lipstick on the pigs you dream up. Your other hobby is
|> | separating fly shit from pepper, under a broken microscope.
|> |
|> | Keep showing everyone what a fool you are. Some people enjoy watching
|> | you go down for the third time, so they can toss you a concrete life
|> | preserver.
|> |
|> | No one expect you to ever learn anything or to admit what a fool you
|> | really are. You make Roy look smart, by comparison.
|>
|> I'm only showing what a fool you are.
|
|
| Tell me, Phil, how low of a line voltage do you expect your fantasy
| UPS to work, without being completely on batteries?

At least one existing UPS can go down to 86 volts or lower for a 120 volt
system. Switch mode power supplies are readily available for the 100 to
240 volt range (check your own computer(s) and see). Just build one big
enough to drive the inverter and charge the battery. Front end it with a
120 volt to 240 volt transformer if you want to power it on 120 volts. Or
just connect it to a 240 volt circuit.

If a switch mode power supply can be made to operate over a 100 to 240 volt
range, then a similar design for a smaller voltage could do 50 to 120 volts
if that is the desired system voltage.

Note that the 100 to 240 volt range is nominal. They do have a wider range
to accomodate voltage variations of 5% or even 10%. Power supply specs I
have seen often say they work down to 90 volts. And this is without looking
for wider range ones. I bet a real electrical engineer would know how to
make one handle 45 to 305 volts input AC with a reasonbly constant DC output
at some voltage.

9. ### Guest

|
| wrote:
|>
|> |
|> | You are so stupid that you hav enver hear of "Thinking outside the
|> | box"?
|>
|> You are quite creative. You have that going for you.
|>
|> I know about "Thinking outside the box". But you didn't specify that
|> box as the one you were referring to before I asked you to.
|
|
| Lame excuse.

Factually accurate. Look back at what you posted (and did not include
in your last post ... how convenient). It could have been any box.

|> | No, I SAID THAT I WOULD USE A BATTERY BANK 50% MORE THEN THE MINIMUM
|> | TO EXTEND ITS LIFE.
|>
|> With some UPSes you can do that. With others, you can't.
|
|
| We were talking a new design so that is a lame answer. Do I have do
| define 'Lame' as well?

Maybe a new design. But I never said I designed it. I never even gave
a design. Yet you acted as if I have provided a design.

Existing designs can be used if full power conversion is acceptable over
the full voltage range, either 100 to 240 volts for a 240 volt system,
or 50 to 120 volts for a 120 volt system. Power supplies (chargers, AC
to DC converters, by any other name) are already designed with this wide
of an input voltage range. The only change in design that might be
needed is model specifics, such as a particular capacity or form factor.
This is stuff electrical engineers frequently do, as evidenced by the
myriad of products like this on the market.

Where a theoretical design change would be needed is when it is desired
to have an upper limit on the current being drawn. At lower voltages
this would mean less power is drawn. That would be needed, for example,
when a nominal power of 1000 watts is working on a 120 volt circuit, and
it is desired to limit the current at 12 amps to operate within the 80%
single dedicated device rating on a 15 amp circuit. Down to 83.333
volts, the full power can be sustained. Below that voltage, the power
level must be reduced to stay within the 12 amp limit. So at 50 volts,
the power would be only 600 watts. If the load being powered is 1000
watts, then 400 watts has to come from the battery. But that's only 40%
of what the battery could carry. If the load being powered is only 600
watts, then the battery has no load at all.

The above figured are based on a hypothetical 100% efficiency ONLY for
the purpose of simplified explanation. In reality efficiency levels
would vary around 90% to 96%. It would complicate the explanation to
use those figures, and make it harder for some people to see what is
going on. In a real product design case, it would be more complicated.
That's the job of the engineer doing the actual design.

|> I *AM* talking about a redesign (without yet doing that redesign) of the
|> charging (AC to DC) component of the UPS so that it will get whatever
|> power it can get from a deep brownout condition, and use that to charge
|> the battery or supplement the use of the battery.
|>
|> It is PLAUSIBLE to do this because switch mode power supplies, which are
|> devices that convert AC to DC at one or more DC output voltages, can
|> readily and easily be made to operate over a voltage range greater than
|> 2:1. Most computer power supplies now do 100 to 240 volts AC continuous,
|> without needing one of those "115/230" switches. Almost all my wall
|> warts do this, too. If it can be done for 100 to 240, it could also be
|> done for 50 to 120, and thus be within the range for the class of deep
|> brownout I have seen about half the time. Or a 240 volt class UPS can
|> be left at the 100 to 240 volt range. What will need to be done to
|> accomodate this is to be sure the current at the low voltage can be
|> handled, or be restricted/limited.
|>
|> So really, I don't even need to design this. It has already been done.
|
|
| Really? Then go buy it.

I already have many such power supplies. What is not available is such
a power supply in an integrated UPS.

|> | Tell me, Phil, how low of a line voltage do you expect your fantasy
|> | UPS to work, without being completely on batteries?
|>
|> At least one existing UPS can go down to 86 volts or lower for a 120 volt
|> system. Switch mode power supplies are readily available for the 100 to
|> 240 volt range (check your own computer(s) and see). Just build one big
|> enough to drive the inverter and charge the battery. Front end it with a
|> 120 volt to 240 volt transformer if you want to power it on 120 volts. Or
|> just connect it to a 240 volt circuit.
|>
|> If a switch mode power supply can be made to operate over a 100 to 240 volt
|> range, then a similar design for a smaller voltage could do 50 to 120 volts
|> if that is the desired system voltage.
|>
|> Note that the 100 to 240 volt range is nominal. They do have a wider range
|> to accomodate voltage variations of 5% or even 10%. Power supply specs I
|> have seen often say they work down to 90 volts. And this is without looking
|> for wider range ones. I bet a real electrical engineer would know how to
|> make one handle 45 to 305 volts input AC with a reasonbly constant DC output
|> at some voltage.
|
|
| Is this fantasy supply for a single computer, or for a room full of
| servers? It makes a huge difference.

It will make a difference when one is being selected for deployment.
While the concept would work across a wide capacity range, it would only
be economical for a smaller scale. I estimate the practical limit would
be around the 6kVA to 10kVA per room or building.

10. ### Guest

| wrote:
|>
|> |
|> | wrote:
|> |>
|> |> |
|> |> | You are so stupid that you hav enver hear of "Thinking outside the
|> |> | box"?
|> |>
|> |> You are quite creative. You have that going for you.
|> |>
|> |> I know about "Thinking outside the box". But you didn't specify that
|> |> box as the one you were referring to before I asked you to.
|> |
|> |
|> | Lame excuse.
|>
|> Factually accurate. Look back at what you posted (and did not include
|> in your last post ... how convenient). It could have been any box.
|
|
| Bull shit.

The creativity, again.

|> |> | No, I SAID THAT I WOULD USE A BATTERY BANK 50% MORE THEN THE MINIMUM
|> |> | TO EXTEND ITS LIFE.
|> |>
|> |> With some UPSes you can do that. With others, you can't.
|> |
|> |
|> | We were talking a new design so that is a lame answer. Do I have do
|> | define 'Lame' as well?
|>
|> Maybe a new design. But I never said I designed it. I never even gave
|> a design. Yet you acted as if I have provided a design.
|
|
| No, I didn't. In fact, you can't even write a decent set of
| specifications. That is the whole point. You post stupid ideas, with
| no groundwork.

You said I designed it wrong. That is the same as you saying I designed it.

|> Existing designs can be used if full power conversion is acceptable over
|> the full voltage range, either 100 to 240 volts for a 240 volt system,
|> or 50 to 120 volts for a 120 volt system. Power supplies (chargers, AC
|> to DC converters, by any other name) are already designed with this wide
|> of an input voltage range. The only change in design that might be
|> needed is model specifics, such as a particular capacity or form factor.
|> This is stuff electrical engineers frequently do, as evidenced by the
|> myriad of products like this on the market.
|
|
| The wide range units switch the input configuration, depending on the
| input voltage and under the control of a custom IC. It isn't a single
| wide range.

Actually, it is a single wide range. This was verified directly with
one of the manufacturers that offered both full range and switched range
models. One thing they said is that extra cost of full range is so low,
now, that it is reaching the savings of having fewer models. There is
some threshold switching that takes place in many models to change
characteristics to make it more optimal at different parts of the range.
For one model I asked about, that change happens at 166 volts RMS.

|> Where a theoretical design change would be needed is when it is desired
|> to have an upper limit on the current being drawn. At lower voltages
|> this would mean less power is drawn.
|
|
| You have that backwards. The switching supply is designed to output a
| fixed voltage, and the lower the input voltage, the higher the input
| current. Also, it may be higher than expected, due to a distorted
| waveform at the AC input. It will attempt to provide the power required
| by the load, as the input current goes up. That is the major flaw in

Again with the inability to read.

I previously in that same post described the normal case of a lower
input voltage having a higher input current. Then I described here the
special case of a current limit. Do you even understand what a current
limit is? Maybe not.

When the current input is limited, and has reached the limit, then the
power input goes down as the voltage goes down. Common power supplies
just shut down at this point. As I said, this case is a "theoretical
design change". But I guess you didn't read those words or even
understand what they meant.

|> That would be needed, for example,
|> when a nominal power of 1000 watts is working on a 120 volt circuit, and
|> it is desired to limit the current at 12 amps to operate within the 80%
|> single dedicated device rating on a 15 amp circuit. Down to 83.333
|> volts, the full power can be sustained. Below that voltage, the power
|> level must be reduced to stay within the 12 amp limit. So at 50 volts,
|> the power would be only 600 watts. If the load being powered is 1000
|> watts, then 400 watts has to come from the battery. But that's only 40%
|> of what the battery could carry. If the load being powered is only 600
|> watts, then the battery has no load at all.
|>
|> The above figured are based on a hypothetical 100% efficiency ONLY for
|> the purpose of simplified explanation. In reality efficiency levels
|> would vary around 90% to 96%. It would complicate the explanation to
|> use those figures, and make it harder for some people to see what is
|> going on. In a real product design case, it would be more complicated.
|> That's the job of the engineer doing the actual design.
|
|
| the losses also depend on operating temperature, battery condition,
| and the percentage the load represents of the UPS design allows. The
| harder you push it, the hotter it runs, and the higher the losses.

I didn't intend to list everything. Thank you for adding to the list so
others who read this have a more complete list.

|> |> I *AM* talking about a redesign (without yet doing that redesign) of the
|> |> charging (AC to DC) component of the UPS so that it will get whatever
|> |> power it can get from a deep brownout condition, and use that to charge
|> |> the battery or supplement the use of the battery.
|> |>
|> |> It is PLAUSIBLE to do this because switch mode power supplies, which are
|> |> devices that convert AC to DC at one or more DC output voltages, can
|> |> readily and easily be made to operate over a voltage range greater than
|> |> 2:1. Most computer power supplies now do 100 to 240 volts AC continuous,
|> |> without needing one of those "115/230" switches. Almost all my wall
|> |> warts do this, too. If it can be done for 100 to 240, it could also be
|> |> done for 50 to 120, and thus be within the range for the class of deep
|> |> brownout I have seen about half the time. Or a 240 volt class UPS can
|> |> be left at the 100 to 240 volt range. What will need to be done to
|> |> accomodate this is to be sure the current at the low voltage can be
|> |> handled, or be restricted/limited.
|> |>
|> |> So really, I don't even need to design this. It has already been done.
|> |
|> |
|> | Really? Then go buy it.
|>
|> I already have many such power supplies. What is not available is such
|> a power supply in an integrated UPS.
|
|
| Then it doesn't exist, and you lied.

The wide range power supplies do exist. So no new design is needed for
the simple case of operating at 60 volts on a 120 volt system, other
than scaling it down from 100-240 to 50-120, which would not be hard.
The slightly harder design, which I am sure any experienced power supply
designer can do, is the current limiting design. But you don't even
understand what current limiting is, so you are way way out of the
running for being able to design such a thing.

|> |> | Tell me, Phil, how low of a line voltage do you expect your fantasy
|> |> | UPS to work, without being completely on batteries?
|> |>
|> |> At least one existing UPS can go down to 86 volts or lower for a 120 volt
|> |> system. Switch mode power supplies are readily available for the 100 to
|> |> 240 volt range (check your own computer(s) and see). Just build one big
|> |> enough to drive the inverter and charge the battery. Front end it with a
|> |> 120 volt to 240 volt transformer if you want to power it on 120 volts. Or
|> |> just connect it to a 240 volt circuit.
|> |>
|> |> If a switch mode power supply can be made to operate over a 100 to 240 volt
|> |> range, then a similar design for a smaller voltage could do 50 to 120 volts
|> |> if that is the desired system voltage.
|> |>
|> |> Note that the 100 to 240 volt range is nominal. They do have a wider range
|> |> to accomodate voltage variations of 5% or even 10%. Power supply specs I
|> |> have seen often say they work down to 90 volts. And this is without looking
|> |> for wider range ones. I bet a real electrical engineer would know how to
|> |> make one handle 45 to 305 volts input AC with a reasonbly constant DC output
|> |> at some voltage.
|> |
|> |
|> | Is this fantasy supply for a single computer, or for a room full of
|> | servers? It makes a huge difference.
|>
|> It will make a difference when one is being selected for deployment.
|> While the concept would work across a wide capacity range, it would only
|> be economical for a smaller scale. I estimate the practical limit would
|> be around the 6kVA to 10kVA per room or building.
|
|
|
| Really? Do you have any ideas what is required to build that
| abomination? I do know, and you won't like the answers.

You've shown you don't even understand many of the concepts. How could
you possibly be able to design these things if you don't even understand
what it is supposed to do? Yeah, I won't like the answer that you can't
accomplish it, if I were in the business of making UPSes. I'd have to
hire a different engineer.

| Show us you know what you claim by describing what has to be done to
| make it operate the way you want, or admit that you are the moron you're
| know to be.

I've already described what it needs to do. It needs to keep supplying
DC power in such a way that the inverter fully operates at up to the
rated inverter load, using all the DC power available from the
converter, and gets else is needed (but no more than this) from the
battery. I'm not talking about the circuit details. Those things have
already been done in other things besides UPSes. This is just a product
design (that's not the same as circuit design) and integration issue.

11. ### Guest

| On Mar 3, 2:03?am, wrote:
|> So, when this low voltage condition exists, why not just go ahead and operate
|> the AC to DC conversion at a level right at the current limit, and obtain the
|> remaining power from the battery? ?By drawing less from the battery, and the
|> most that is still safe from what can be gotten from the low utility voltage,
|> the battery can last longer than it otherwise would. ?Is it too complex or
|> costly to make an AC to DC conversion (basically apower supply) section that
|> would operate on these lower voltages? ?
|
| Yes. UPSes are designed as cheap as possible. Some have seen how
| cheap. Replacing a UPS is sometimes less expensive than replacing its
| battery. Why make it more complex and more expensive?
|
| Second, UPS battery is charged by a power supply equivalent to a
| wall wart. To accomplish what you have suggested means that battery
| charging power supply must be larger: increased costs. Or it must
| have an even larger operating input voltage - again increased costs.
| Just another reason why it is not done.

How much larger does it get just to extend its lower voltage range?
How much larger does it get to make that extended lower voltage come
with a constant current level at a certain current limit?

| Third, AC utilities providing voltages at that low level is a
| specification violation. It rarely happens. If detected, utility
| typically cuts all power off due to defects that might cause such low
| voltages. IOW a more complex UPS circuit and the larger battery
| charger would rarely prosper from such a condition. Better is to get
| you to buy a larger (more expensive) UPS - and keep this UPS as cheap
| as possible.

Utility equipment is also done on the cheap. I've seen the half voltage
scenario ssveral times in different places. In one instance it persisted
for over 4 hours. In theory, a phase loss detector in a transformer should
signal an upstream cutoff. It doesn't always happen.

This is one reason (there are others, too) I'm wanting to run my computers
directly on 240 volts. If there's a deep brownout, they can still run in
that condition. The impediments to doing this include finding the right
surge protection (easy for entrance protectors, hard for point of use) and
the fact that existing UPSes defeat the ability to operate over the wide
voltage range (why I raised this issue to begin with).

A battery charger (in a UPS or as part of a separate component system)
that can be set to specific power or current limits can also be useful
in using small generators to supplement the battery in a total loss of
power.

| Fourth, if a low voltage condition exists, unstable AC power is best
| disconnected from equipment anyway. Maintaining voltage too low can
| be harmful to electric motors and to the distribution system.
| Therefore, when that defect is detected, reliability says better is to
| disconnect.

For anything that increases the current, and is not rated for that increase
in current. That's why my idea of making the power supply component have a
current limit and just scale down its power intake, stretching the battery
run time.

| Fifth, a UPS is for saving data. Making the UPS more complex for a
| rare type of failure is not useful. If a UPS needed to operate
| longer, then the UPS is too small anyway. Better is to get you to buy
| the more expensive UPS with a bigger battery.

What the UPS is for depends on the scenario. In many cases I have seen,
especially for ISPs and web services, it's to ride out power outages.
The sizing is done by CFOs. Batteries are the biggest part of the cost.

| Those UPSes are designed to sell mostly on price - as cheap as
| possible. Why do anything to make its price higher? Five different
| reasons why the suggestion is not useful.

An increase in charger cost, that can provide longer batter run time than
an the increase in battery capacity of the same cost, provides more run
time for the dollar.

This is why I often have the desire to just build a UPS from separate
components. I'm not an electrical engineer. At best I am an electrical
hobbyist.

| Michael is a technician. He knows what a technician knows - what to
| do. He often does not know why - what an engineer learns. Therefore
| he has a repeat habit of attacking others because he does not know
| why. Attacking others is trick often used to mask the posters
| technical naivety. Unfortunately it works because others see the
| insults and then believe the insulter. Rather than learn the facts,
| many instead believe the first one to post insults. It is also how
| Rush Limbaugh operates.

I've known many technicians (and engineers). I've also listened to a few
radio talk show hosts, and watched equivalent ones on TV (such as Glen Beck).
Most manage to remain respectable. There are exceptions like Michael and
Rush.

I've learned years ago that when I see someone insulting someone else online,
and not just on Usenet, that it more likely means the insulter is upset at
something. I've also learned that it can be hard to find out just what that
is because so many cases are merely a misunderstanding somewhere.

12. ### Don KellyGuest

As an engineer, (and retired EE professor) , I have learned to listen to
technicians and gain from doing so. I have tried to teach future
engineers to recognize that they can find the difference between those
with many years of experience and those with one year's experience,
repeated many times- and learn from the former.
I am not impressed with those who say "I am an engineer and he is <just>
a technician'. Such a statement says more about the deficits of the
"engineer" than those of the "technician".
Both you and Phil have useful things to say. Neither needs to hurl
insults. I don't agree with all either of you have to say, nor do you
agree with me on everything. Fair enough- unfortunately, on the net it
is difficult to sit down and have a beer together and sort things out
properly.

13. ### Guest

|
| wrote:
|>
|> | On Mar 3, 2:03?am, wrote:
|> |> So, when this low voltage condition exists, why not just go ahead and operate
|> |> the AC to DC conversion at a level right at the current limit, and obtain the
|> |> remaining power from the battery? ?By drawing less from the battery, and the
|> |> most that is still safe from what can be gotten from the low utility voltage,
|> |> the battery can last longer than it otherwise would. ?Is it too complex or
|> |> costly to make an AC to DC conversion (basically apower supply) section that
|> |> would operate on these lower voltages? ?
|> |
|> | Yes. UPSes are designed as cheap as possible. Some have seen how
|> | cheap. Replacing a UPS is sometimes less expensive than replacing its
|> | battery. Why make it more complex and more expensive?
|> |
|> | Second, UPS battery is charged by a power supply equivalent to a
|> | wall wart. To accomplish what you have suggested means that battery
|> | charging power supply must be larger: increased costs. Or it must
|> | have an even larger operating input voltage - again increased costs.
|> | Just another reason why it is not done.
|>
|> How much larger does it get just to extend its lower voltage range?
|> How much larger does it get to make that extended lower voltage come
|> with a constant current level at a certain current limit?
|
|
| That depends on how much you want to supplement the batteries, and if
| it is even possible to draw the additional current from the AC line in a
| brownout condition. Every thing in the input stage has to be larger,
| including the circuit supplying power to the UPS & computers. The
| switching supply will need larger electrolytics, heavier rectifiers,
| more switching transistors, and a bigger switching transformer for the
| charger. You will need to add fans, or use huge heatsink. Some UPS
| use the same transformer to charge the batteries and for the output
| transformer, so you would need a complete new charging circuit.

So you are questioning the ability to draw current when the voltage is
at half level? If you can't, then that means there is a systematic
impedance change. Do you have in mine where that change is? Or are you
just trying to be difficult.

Not everything has to be larger.

If it is a limited power device, then the current could double for half
the voltage. Components dealing with the incresaed current will need to
be larger. Once the device has the voltage at a fixed working level to
derive other voltages, then part is just the same size.

If it is a limited current device, then very little will need to be
increased in size. There will have to be added the circuitry to limit
the current when it reaches a certain level.

| High current supplies like that can catch on fire. The Northern
| Telecom PBAX telephone system we had at Microdyne caught fire and smoked
| damaged 80,000 square feet of office, engineering, production and
| storage space. It took over three months to repair the offices near the
| fire, and you could still smell the smoke a year later. Our insurance
| paid for all the repairs, then sued the OEM. The damage came close to
| putting us out of business. Luckily, the phone room was in the
| engineering department, and some of the people could work from home, but
| it dropped productivity quite a bit. If any part of that system was
| home brewed, we would have had to pay for the repairs ourselves. The
| system was in a locked room, and caught fire late one night. if someone
| who was driving through that industrial park hadn't noticed the orange
| glow, we would have lost all the offices, both stockrooms and all of the
| engineering department.

If we are dealing with a constant power device, then a 1000 watt model
will have current levels at half voltage similar to a 2000 watt model at
nominal voltage. Are you saying that the 2000 watt model is more of a
fire risk than the 1000 watt model ... AND is so much more of a risk
that such current levels should be avoided?

If we are dealing with a constant current device, then "high current" is
a constant.

|> | Third, AC utilities providing voltages at that low level is a
|> | specification violation. It rarely happens. If detected, utility
|> | typically cuts all power off due to defects that might cause such low
|> | voltages. IOW a more complex UPS circuit and the larger battery
|> | charger would rarely prosper from such a condition. Better is to get
|> | you to buy a larger (more expensive) UPS - and keep this UPS as cheap
|> | as possible.
|>
|> Utility equipment is also done on the cheap. I've seen the half voltage
|> scenario ssveral times in different places. In one instance it persisted
|> for over 4 hours. In theory, a phase loss detector in a transformer should
|> signal an upstream cutoff. It doesn't always happen.
|
|
| Phase loss detection is the customer's problem, and is solved by using
| a PLM and either drive an alarm, or use it to shut down equipment that
| is easily damaged. There was a company in Leesburg, Florida making
| them. They were small enough to hold in your hand and made to mount
| with typical industrial relays and timer modules. if you lose a phase,
| but have some large 3 Phase AC motors running at the time, they will
| continue to run, but draw the additional current from the other phases,
| causing the motor to run hotter. Look up 'Rotary Phase Converter'

If a phase loss results in nominal voltage on 2 phases and zero on a
third phase, then that would be a phase loss to the customer. However,
if the utility wires things in such a way that a phase loss upstream
results in half voltage to SINGLE PHASE customers for an extended period
of time, then that is a utility problem.

|> This is one reason (there are others, too) I'm wanting to run my computers
|> directly on 240 volts. If there's a deep brownout, they can still run in
|> that condition. The impediments to doing this include finding the right
|> surge protection (easy for entrance protectors, hard for point of use) and
|> the fact that existing UPSes defeat the ability to operate over the wide
|> voltage range (why I raised this issue to begin with).
|
|
| Take a careful look at the power supplies you are considering,
| because a lot have a dead band between the two voltage ranges. All they
| do is sense the input and select 120 or 240 range to keep the costs
| down I see them specified as 90-130 & 180-260, leaving a dead band
| between 130-180 volts where operation isn't guaranteed.

Many are that way. Many more are full range. Full range is becoming
more and more common. Maybe you should take the careful look.

|> A battery charger (in a UPS or as part of a separate component system)
|> that can be set to specific power or current limits can also be useful
|> in using small generators to supplement the battery in a total loss of
|> power.
|
|
| if you buy a small generator, get one with an accurate governor, or
| that is a DC/inverter package like some of the Hondas.

And regulator.

|> | Fourth, if a low voltage condition exists, unstable AC power is best
|> | disconnected from equipment anyway. Maintaining voltage too low can
|> | be harmful to electric motors and to the distribution system.
|> | Therefore, when that defect is detected, reliability says better is to
|> | disconnect.
|>
|> For anything that increases the current, and is not rated for that increase
|> in current. That's why my idea of making the power supply component have a
|> current limit and just scale down its power intake, stretching the battery
|> run time.
|
|
| You can't limit it very much and have anything useful.

With limited current, you can have half power at half voltage. That may
only be half as useful, but it can be useful. For example, if the UPS
is fully loaded, half the power needed to run the loads can be drawn
from AC and the other half from the battery ... instead of all from the
battery.

|> | Fifth, a UPS is for saving data. Making the UPS more complex for a
|> | rare type of failure is not useful. If a UPS needed to operate
|> | longer, then the UPS is too small anyway. Better is to get you to buy
|> | the more expensive UPS with a bigger battery.
|>
|> What the UPS is for depends on the scenario. In many cases I have seen,
|> especially for ISPs and web services, it's to ride out power outages.
|> The sizing is done by CFOs. Batteries are the biggest part of the cost.
|
|
| If the CFO is so cheap that he is willing to use home brew backup
| power, its time to find another job. The costs to get a custom system
| through UL approval will buy several lifetimes worth of batteries. Do
| you have a PE willing to sign off on your modifications? Will you be
| able to find fire insurance for the business that will pay a claim after
| a fire?

The CFO sets the price limit. It's called a budget. Engineering can
sometimes wiggle this some. But not always. Or not generally by a
great deal.

So, where batteries are the substantial cost, and there is the real
possibility of getting half the voltage for some reason, then a UPS
system that works this way and provide more run time on that fixed
battery capacity.

There is a valid market issue. Is there a market for such a device?
Probably not. Can it be designed? I think it can. The components have

|> | Those UPSes are designed to sell mostly on price - as cheap as
|> | possible. Why do anything to make its price higher? Five different
|> | reasons why the suggestion is not useful.
|>
|> An increase in charger cost, that can provide longer batter run time than
|> an the increase in battery capacity of the same cost, provides more run
|> time for the dollar.
|
|
| Not if it isn't legal to use. If the fire inspector sees a homebrew
| UPS during any visit, he is allowed to have the power to the building
| turned off till it is removed. You still don't see the big picture,
| Phil. Its one thing to homebrew a power supply to use at home, but for
| a business, it is a huge liability.

If it is an engineered custom design, this is not true. Businesses have
various kinds of systems custom designed for them all the time.

|> This is why I often have the desire to just build a UPS from separate
|> components. I'm not an electrical engineer. At best I am an electrical
|> hobbyist.
|
|
| Do the math, Phil. The extra hardware costs, plus the testing &
| added liability costs quickly wipe out any possible savings. An
| properly sized generator with an automatic transfer switch is cheaper
| than getting a custom UPS approved for commercial use. if the generator
| is propane powered, it won't have a problem with the fuel going bad
| while in storage.

If YOU have done the math on the hardware component costs, then YOU have
done a design.

|> | Michael is a technician. He knows what a technician knows - what to
|> | do. He often does not know why - what an engineer learns. Therefore
|> | he has a repeat habit of attacking others because he does not know
|> | why. Attacking others is trick often used to mask the posters
|> | technical naivety. Unfortunately it works because others see the
|> | insults and then believe the insulter. Rather than learn the facts,
|> | many instead believe the first one to post insults. It is also how
|> | Rush Limbaugh operates.
|>
|> I've known many technicians (and engineers). I've also listened to a few
|> radio talk show hosts, and watched equivalent ones on TV (such as Glen Beck).
|> Most manage to remain respectable. There are exceptions like Michael and
|> Rush.
|
|
| Why? Because I tell you something is flawed, and you never listen?

It's more a case of not believing you because you have a track record of
saying some of the dumbest things I've heard online.

| I have worked in electronics my whole life, including manufacturing of
| power supplies. I also qualified new suppliers for the few switching
| power supplies we bought, and dequalifed multiple vendors when the
| shipped product didn't match the build quality of the test samples. One
| of the TV stations I worked at had 500 KW diesel generators for backup
| power, and the only UPS was for the video automation computer. A few
| battery powered emergency lights were mounted around the walls, but if
| the three generators didn't start, two UHF TV stations, five 50 KW FM
| without power for their equipment.

|> I've learned years ago that when I see someone insulting someone else online,
|> and not just on Usenet, that it more likely means the insulter is upset at
|> something. I've also learned that it can be hard to find out just what that
|> is because so many cases are merely a misunderstanding somewhere.
|
|
| The only way to get some people's attention is to resort to insults
| and you are know for hurling your share of insults, as well.

I go to extra effort to avoid using insults. For a few people like you,
that gets to be very hard to do, and sometimes it just has to happen.
But check your own posts. You'll see insults generally begin with your
first followup post in the original thread.

14. ### Guest

| Sigh. Do it. Design it, build it, and use it. Then see what
| happens during a brownout.

I'll buy it when it comes out as an integrated product.

|> Not everything has to be larger.
|
|
| Give details on what doesn't need modified, since you have all the

It's an integration project. Just put a wide range power supply in
place of the narrow range power supply, and change the control logic to
allow wide range operation.

|> If it is a limited power device, then the current could double for half
|> the voltage. Components dealing with the incresaed current will need to
|> be larger. Once the device has the voltage at a fixed working level to
|> derive other voltages, then part is just the same size.
|>
|> If it is a limited current device, then very little will need to be
|> increased in size. There will have to be added the circuitry to limit
|> the current when it reaches a certain level.
|
|
| If it is current limited, it will be of little use. The existing
| charger may take up to 24 hours for a complete charge, and would give
| you less than 10% of the battery's A/Hr rating. Think about it: 24
| hours to fully charge, and 15 minutes to run them down.

The current limit is for operation at lower voltage, reduced power. One
doesn't recharge the battery unless there is sufficient input power
available to do that. Many current UPS designs use about 1 amp input to
recharge after a long usage. Rapid recharge is not much of a demand.
It could be done, but as you know, you'll need a larger circuit for it.

|> | High current supplies like that can catch on fire. The Northern
|> | Telecom PBAX telephone system we had at Microdyne caught fire and smoked
|> | damaged 80,000 square feet of office, engineering, production and
|> | storage space. It took over three months to repair the offices near the
|> | fire, and you could still smell the smoke a year later. Our insurance
|> | paid for all the repairs, then sued the OEM. The damage came close to
|> | putting us out of business. Luckily, the phone room was in the
|> | engineering department, and some of the people could work from home, but
|> | it dropped productivity quite a bit. If any part of that system was
|> | home brewed, we would have had to pay for the repairs ourselves. The
|> | system was in a locked room, and caught fire late one night. if someone
|> | who was driving through that industrial park hadn't noticed the orange
|> | glow, we would have lost all the offices, both stockrooms and all of the
|> | engineering department.
|>
|> If we are dealing with a constant power device, then a 1000 watt model
|> will have current levels at half voltage similar to a 2000 watt model at
|> nominal voltage. Are you saying that the 2000 watt model is more of a
|> fire risk than the 1000 watt model ... AND is so much more of a risk
|> that such current levels should be avoided?
|
|
| Constant load, maybe, but there is the law of 'Conservation Of
| Energy', and all your dancing can't get yo around that. You have losses
| building. If you don't remove the heat, the equipment dies a lot
| faster, adding to the capital equipment costs.

So you think there is more heat produced at lower power?

|> If we are dealing with a constant current device, then "high current" is
|> a constant.
|
|
| The only constant current is into the load. if there isn't enough
| available, you get data errors, or crashes.

The idea is to provide a constant voltage to the load, and shutdown when
not enough power is available to do that.

|> |> | Third, AC utilities providing voltages at that low level is a
|> |> | specification violation. It rarely happens. If detected, utility
|> |> | typically cuts all power off due to defects that might cause such low
|> |> | voltages. IOW a more complex UPS circuit and the larger battery
|> |> | charger would rarely prosper from such a condition. Better is to get
|> |> | you to buy a larger (more expensive) UPS - and keep this UPS as cheap
|> |> | as possible.
|> |>
|> |> Utility equipment is also done on the cheap. I've seen the half voltage
|> |> scenario ssveral times in different places. In one instance it persisted
|> |> for over 4 hours. In theory, a phase loss detector in a transformer should
|> |> signal an upstream cutoff. It doesn't always happen.
|> |
|> |
|> | Phase loss detection is the customer's problem, and is solved by using
|> | a PLM and either drive an alarm, or use it to shut down equipment that
|> | is easily damaged. There was a company in Leesburg, Florida making
|> | them. They were small enough to hold in your hand and made to mount
|> | with typical industrial relays and timer modules. if you lose a phase,
|> | but have some large 3 Phase AC motors running at the time, they will
|> | continue to run, but draw the additional current from the other phases,
|> | causing the motor to run hotter. Look up 'Rotary Phase Converter'
|>
|> If a phase loss results in nominal voltage on 2 phases and zero on a
|> third phase, then that would be a phase loss to the customer. However,
|> if the utility wires things in such a way that a phase loss upstream
|> results in half voltage to SINGLE PHASE customers for an extended period
|> of time, then that is a utility problem.
|
|
| It is their responsibility to make quick repairs, it is up to the
| customer to protect their equipment.

That doesn't always happen, for many reasons.

|> |> This is one reason (there are others, too) I'm wanting to run my computers
|> |> directly on 240 volts. If there's a deep brownout, they can still run in
|> |> that condition. The impediments to doing this include finding the right
|> |> surge protection (easy for entrance protectors, hard for point of use) and
|> |> the fact that existing UPSes defeat the ability to operate over the wide
|> |> voltage range (why I raised this issue to begin with).
|> |
|> |
|> | Take a careful look at the power supplies you are considering,
|> | because a lot have a dead band between the two voltage ranges. All they
|> | do is sense the input and select 120 or 240 range to keep the costs
|> | down I see them specified as 90-130 & 180-260, leaving a dead band
|> | between 130-180 volts where operation isn't guaranteed.
|>
|> Many are that way. Many more are full range. Full range is becoming
|> more and more common. Maybe you should take the careful look.
|
|
| I have, and I don't like the specifications on a lot of them. Too
| much ripple, and other problems. Look at the efficiency of some when
| not operated near the two nominal voltages, as well. There are no idiot
| proof designs, but overly complex designs will come back to cause major
| problems, more often.

I have found that computer power supplies of the 100-240 volt design do
run more efficiently at 240 volts. Is that what you are referring to?

|> |> A battery charger (in a UPS or as part of a separate component system)
|> |> that can be set to specific power or current limits can also be useful
|> |> in using small generators to supplement the battery in a total loss of
|> |> power.
|> |
|> |
|> | if you buy a small generator, get one with an accurate governor, or
|> | that is a DC/inverter package like some of the Hondas.
|>
|> And regulator.
|
|
| Show me any commercially available genset designed for autostart &
| transfer switch that isn't regulated properly.

|> |> | Fourth, if a low voltage condition exists, unstable AC power is best
|> |> | disconnected from equipment anyway. Maintaining voltage too low can
|> |> | be harmful to electric motors and to the distribution system.
|> |> | Therefore, when that defect is detected, reliability says better is to
|> |> | disconnect.
|> |>
|> |> For anything that increases the current, and is not rated for that increase
|> |> in current. That's why my idea of making the power supply component have a
|> |> current limit and just scale down its power intake, stretching the battery
|> |> run time.
|> |
|> |
|> | You can't limit it very much and have anything useful.
|>
|> With limited current, you can have half power at half voltage. That may
|> only be half as useful, but it can be useful. For example, if the UPS
|> is fully loaded, half the power needed to run the loads can be drawn
|> from AC and the other half from the battery ... instead of all from the
|> battery.
|
|
| Like I said several times before, the waveform is less than ideal during
| brownout conditions. Do you monitor the line voltage with a true RMS
| meter, or a cheap DVM? You need to look at the AC line with a scope
| during brownouts, and other problems to see what crap the equipment has
| to deal with.

I'll let you know.

|> |> | Fifth, a UPS is for saving data. Making the UPS more complex for a
|> |> | rare type of failure is not useful. If a UPS needed to operate
|> |> | longer, then the UPS is too small anyway. Better is to get you to buy
|> |> | the more expensive UPS with a bigger battery.
|> |>
|> |> What the UPS is for depends on the scenario. In many cases I have seen,
|> |> especially for ISPs and web services, it's to ride out power outages.
|> |> The sizing is done by CFOs. Batteries are the biggest part of the cost.
|> |
|> |
|> | If the CFO is so cheap that he is willing to use home brew backup
|> | power, its time to find another job. The costs to get a custom system
|> | through UL approval will buy several lifetimes worth of batteries. Do
|> | you have a PE willing to sign off on your modifications? Will you be
|> | able to find fire insurance for the business that will pay a claim after
|> | a fire?
|>
|> The CFO sets the price limit. It's called a budget. Engineering can
|> sometimes wiggle this some. But not always. Or not generally by a
|> great deal.
|
|
| A budget is a goal. Some are reasonable, some aren't. Sometimes you
| have to walk away from the CFO and let them find out for themselves.
| BTDT. They told me I was unreasonable with my costs, then found out
| everyone else wanted three to ten times as much. In some cases they
| spent the money. in others, they had to scale down their plans, or
| delay them till more money was available. A CFO operates on greed.
| Engineers operate on logic.

And what do you techs operate on?

|> So, where batteries are the substantial cost, and there is the real
|> possibility of getting half the voltage for some reason, then a UPS
|> system that works this way and provide more run time on that fixed
|> battery capacity.
|
|
| SO what? Either you can afford to be in business, or you can't. It
| sounds like a shoestring operation that is about to close its doors.

Or a startup. Or in survival mode. Businesses do pull through when
money has a dry spell.

|> There is a valid market issue. Is there a market for such a device?
|> Probably not. Can it be designed? I think it can. The components have
|
|
| labor, and costs for rent for the floor space for the additional
| equipment, the extra air conditioning costs, preventative maintences
| costs, stocking spare parts for the custom equipment, documenting the
| project, and estimated service life before it needs a major overhaul, or
| complete replacement. Then compare that to the battery costs for a
| decent genset & switch plus fuel. Then figure out what would happen if
| you needed to increase the capacity, say another 20% because the new
| servers needed it. You never want to design a system too close to the
| limits, like I have pointed out before. A proper de-reating is needed.
| If you do get extended time for the servers, what happens when they
| overheat because there is no AC?

I'm suggesting that it be designed, not suggesting that it already exists.

|> |> | Those UPSes are designed to sell mostly on price - as cheap as
|> |> | possible. Why do anything to make its price higher? Five different
|> |> | reasons why the suggestion is not useful.
|> |>
|> |> An increase in charger cost, that can provide longer batter run time than
|> |> an the increase in battery capacity of the same cost, provides more run
|> |> time for the dollar.
|> |
|> |
|> | Not if it isn't legal to use. If the fire inspector sees a homebrew
|> | UPS during any visit, he is allowed to have the power to the building
|> | turned off till it is removed. You still don't see the big picture,
|> | Phil. Its one thing to homebrew a power supply to use at home, but for
|> | a business, it is a huge liability.
|>
|> If it is an engineered custom design, this is not true. Businesses have
|> various kinds of systems custom designed for them all the time.
|
|
| If it is custom engineered and can affect employee safety, someone is
| liable if it has a catastrophic failure.

And?

|> |> This is why I often have the desire to just build a UPS from separate
|> |> components. I'm not an electrical engineer. At best I am an electrical
|> |> hobbyist.
|> |
|> |
|> | Do the math, Phil. The extra hardware costs, plus the testing &
|> | added liability costs quickly wipe out any possible savings. An
|> | properly sized generator with an automatic transfer switch is cheaper
|> | than getting a custom UPS approved for commercial use. if the generator
|> | is propane powered, it won't have a problem with the fuel going bad
|> | while in storage.
|>
|> If YOU have done the math on the hardware component costs, then YOU have
|> done a design.
|
|
| I have doe it before, and it never made sense. I don't have the
| numbers in front of me to do a full design, but you should, even before
| considering a custom system.

So you have had a NEED to make a UPS like I suggested?

|> |> I've known many technicians (and engineers). I've also listened to a few
|> |> radio talk show hosts, and watched equivalent ones on TV (such as Glen Beck).
|> |> Most manage to remain respectable. There are exceptions like Michael and
|> |> Rush.
|> |
|> |
|> | Why? Because I tell you something is flawed, and you never listen?
|>
|> It's more a case of not believing you because you have a track record of
|> saying some of the dumbest things I've heard online.
|
|
| Funny. I heard that, and more about you.

Maybe my suggestion is a dumb one. But you've not yet given a sane
argument why it would be. Your posting style is more along the lines of
giving dumb answer and making insults without details. I'll continue to
think outside the box and come up with ideas. There will be dumb ones.
Those are supposed to be shot down on merit, or just ignored. Your
past reactions have been some combination of insult and ignore. You're
not useful.

|> | I have worked in electronics my whole life, including manufacturing of
|> | power supplies. I also qualified new suppliers for the few switching
|> | power supplies we bought, and dequalifed multiple vendors when the
|> | shipped product didn't match the build quality of the test samples. One
|> | of the TV stations I worked at had 500 KW diesel generators for backup
|> | power, and the only UPS was for the video automation computer. A few
|> | battery powered emergency lights were mounted around the walls, but if
|> | the three generators didn't start, two UHF TV stations, five 50 KW FM
|> | without power for their equipment.
|>
|
|
| So have you, but you seem to always omit any details needed to help
| you.

Where the details would be relevant, I'll provide them.

|> |> I've learned years ago that when I see someone insulting someone else online,
|> |> and not just on Usenet, that it more likely means the insulter is upset at
|> |> something. I've also learned that it can be hard to find out just what that
|> |> is because so many cases are merely a misunderstanding somewhere.
|> |
|> |
|> | The only way to get some people's attention is to resort to insults
|> | and you are know for hurling your share of insults, as well.
|>
|> I go to extra effort to avoid using insults. For a few people like you,
|> that gets to be very hard to do, and sometimes it just has to happen.
|> But check your own posts. You'll see insults generally begin with your
|> first followup post in the original thread.
|
|
| You still haven't given anything useful, other than your usual wish
| list. No good design starts with a dart board or 'magic 8 ball'.
| Solid, reasonable specifications are always the first step. Without
| those, it is a complete waste of time.

Yes, I do toss out wish list items. Now you're recognizing that. And
of course some will be usless in the market and others impractical to
make. You seem to have a lack of ability to properly recognize either
reason.

15. ### Guest

| wrote:
|>
|>
|> | Sigh. Do it. Design it, build it, and use it. Then see what
|> | happens during a brownout.
|>
|> I'll buy it when it comes out as an integrated product.
|
|
|
|
|
|> It's an integration project. Just put a wide range power supply in
|> place of the narrow range power supply, and change the control logic to
|> allow wide range operation.
|
|
| Then do it.

That's for the product integrator to do.

|> The current limit is for operation at lower voltage, reduced power. One
|> doesn't recharge the battery unless there is sufficient input power
|> available to do that. Many current UPS designs use about 1 amp input to
|> recharge after a long usage. Rapid recharge is not much of a demand.
|> It could be done, but as you know, you'll need a larger circuit for it.
|
|
| Reducing the current during a brownout? Right. Where did I mention
| recharging during a brownout?

I didn't say reduce it. I said limit it. That is, do not let it rise
above the maximum current that can be handled safely for either the
device or the supply circuit that feeds it. This would be a POWER
reduction. As for the charging, I'm explaining to you that UPS battery
charging is just a small portion of the current drawn. A rapid bettery
charge would draw a lot of current. UPS batteries are not generally
intended for rapid recharging, anyway.

|> | Constant load, maybe, but there is the law of 'Conservation Of
|> | Energy', and all your dancing can't get yo around that. You have losses
|> | building. If you don't remove the heat, the equipment dies a lot
|> | faster, adding to the capital equipment costs.
|>
|> So you think there is more heat produced at lower power?
|
|
| Sigh. Read it again, in context. You can't get something for
| nothing, TANSTAAFL, COE. They all mean that you can't add current to
| the input of the output inverter if you limit it to a useless level.
| With your wide range line input concept, as the line voltage goes down
| the current has to go up to provide the same VA. If you limit the
| additional VA, you gain nothing. If you do provide enough to help, the
| I/R losses will be higher, you will put a lot more stress on the input
| stage of the power supply, as well as the switching transistors. You
| can have Fast, Cheap, or Efficient. Pick any two.

The same VA from the DC-AC inverter would draw part from the battery and
part from the AC-DC converter. The AC-DC converter would NOT be
providing the same VA as if it were supplying all the power the load
needs.

The rest of that paragraph is irrelevant since it assumes facts not true.

|> The idea is to provide a constant voltage to the load, and shutdown when
|> not enough power is available to do that.
|
|
| How do you plan to maintain the voltage, when you limit the current?
| (Think: Ohm's law)

The DC-AC inverter is operating from a constant voltage from the battery
and the AC-DC power supply. The power supply can produce a constant DC
voltage out over a wide range of AC input voltages.

|> | It is their responsibility to make quick repairs, it is up to the
|> | customer to protect their equipment.
|>
|> That doesn't always happen, for many reasons.
|
|
| Really? Then you are either in a bad location, or there has been a
| disaster and trying to squeeze a few more minutes out of the batteries
| isn't going to help in either situation.

All the brownout scenerios I have experienced were from common storm
damage. Power companies are often slow to respond to this kind of
damage because each incident is not particularly expected on a long term
basis, as compared to something like a Hurricane. People have to come
in to work, get prepared, load up trucks, and head out to known problem
locations. In the case of transmission line voltage work, this could
involve significant travel distance and time.

|> I have found that computer power supplies of the 100-240 volt design do
|> run more efficiently at 240 volts. Is that what you are referring to?
|
|
| No. Look at the specifications and see for yourself. The efficiency
| peaks around the two designated line voltages, and slopes down on either
| side.

Many do have dips in the middle, but they are not severe. Most have a
higher peak at the 240 volt level than at the 120 volt level. Computers
do work in places like Afghanistan where the "voltage of the day" is a
crap-shoot between 160 and 210 volts.

|> | Show me any commercially available genset designed for autostart &
|> | transfer switch that isn't regulated properly.
|>
|
|
| It was your claim that you needed to add a regulator to
| specifications, so its up to you to prove me wrong.

You are the one that wanted a commercially available genset design.

|> | A budget is a goal. Some are reasonable, some aren't. Sometimes you
|> | have to walk away from the CFO and let them find out for themselves.
|> | BTDT. They told me I was unreasonable with my costs, then found out
|> | everyone else wanted three to ten times as much. In some cases they
|> | spent the money. in others, they had to scale down their plans, or
|> | delay them till more money was available. A CFO operates on greed.
|> | Engineers operate on logic.
|>
|> And what do you techs operate on?
|
|
| How long is a string? Could you be a little bit more vague? What
| kind of tech? What budget? How high in the company is he or she? Are
| there company guidelines setting time limits or material cost? How old
| is the equipment? How critical is it? Is it company owned, or your
| customer's property? Is it under warranty or a service contract? Can
| it be replaced for a reasonable multiple of the repair costs? Can a
| replacement be found in time? Is it worth the cost to repair, or so
| unreliable that it is N.E.R.?

You seemed to explain the CFO and engineer roles in some single words.
I was expecting something equally simple (e.g. one word) for techs.
Since you are one, I'd think you'd know.

|> | SO what? Either you can afford to be in business, or you can't. It
|> | sounds like a shoestring operation that is about to close its doors.
|>
|> Or a startup. Or in survival mode. Businesses do pull through when
|> money has a dry spell.
|
|
| If a startup can't afford the equipment it needs, its chances of
| survival are almost zero. The same goes for survival mode. If a
| company finds itself in that mode without being ready, it should die.
| Businesses can and do survive a dry spell, as long as they are well run
| and can pay their bills on time.

There are boundary conditions even in business. Have a look at the top
20 big banks in the USA right now. There are banks where some infusion
of cash can make the difference. The only reason we would give them any
is because them failing would drag everything else down with them like

|> I'm suggesting that it be designed, not suggesting that it already exists.
|
|
| Anything can be 'designed'. Rube Goldberg is proof of that.

Fine. Maybe someone will do it.

|> | If it is custom engineered and can affect employee safety, someone is
|> | liable if it has a catastrophic failure.
|>
|> And?
|
|
| Liability. Look it up. See what the insurance costs are. See if
| the building and zoning department will let you play Frankenstein in a
| location not designated heavy industry, or if they will knowingly
| respond to a fire or explosion at your location because you use non
| approved equipment. Did you ever wonder why paper mills, and some other
| industries not only have sprinkler systems, but a trained crew and a
| fire truck?

So you are saying custom engineering has no place in commerce?

| No, anyone who doesn't agree 100% with you is not useful to you.

There have been others that don't agree with me, and even find something
I said that was wrong, and simply pointed it out. They pointed at the
specific point of disagreement or error, instead of just making a
personal attack.

|> | You still haven't given anything useful, other than your usual wish
|> | list. No good design starts with a dart board or 'magic 8 ball'.
|> | Solid, reasonable specifications are always the first step. Without
|> | those, it is a complete waste of time.
|>
|> Yes, I do toss out wish list items. Now you're recognizing that.
|
|
| No, I've seen it from the beginning, but you don't pay attention to
| what people tell you. Blue sky is pretty to look at, but useless in

You just get upset when people don't agree with you, and you call it not
paying attention. I'm quite open minded. But it takes real information
to change my mind. Personal attacks don't achieve that.

|> You seem to have a lack of ability to properly recognize either
|> reason.
|
|
| Right. I can take a look at an idea and make a good decision on
| whether it is practical with current technology. You post vague ideas,
| then get upset when people don't offer you millions for your brilliance.

No. I get upset when someone makes a personal attack, or makes an
assumption in error about what I said.

| You should go over to and debate electric cars and
| spiral plowing farms with tethered electric powered farm tractors with
| Bret Cahil. All of his ideas are blue sky, so you two have a lot in
| common.

No way. I'm keeping my perpetual motion machine all to myself!