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Power Factor Correction laptops and modified sine wave UPS?

 
 
Ron Hardin
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      07-31-2011, 11:06 PM
Do any Dell laptops find themselves unable to power from a modified sine
wave UPS?

No use springing for a sinewave UPS unless necessary.

So far I haven't noticed laptops failing but I suppose one might secretly
be on its own battery power and I didn't realize it.
--
(E-Mail Removed)

On the internet, nobody knows you're a jerk.
 
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RnR
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      08-01-2011, 05:17 AM
On Sun, 31 Jul 2011 19:06:58 -0400, Ron Hardin
<(E-Mail Removed)> wrote:

>Do any Dell laptops find themselves unable to power from a modified sine
>wave UPS?
>
>No use springing for a sinewave UPS unless necessary.
>



If I recall correctly, this has already been discussed here and no
need for special UPSs (anyone pls correct me if I'm wrong). Aside
from this, I still don't understand what a PowerFactor is and I recall
having a part of a lecture one day in an Electrical Engineering
college class going over it (I'm not an EE). I've also read about it
in a usenet newsgroup and still didn't quite get it but I also gather
it doesn't get used much my EEs (tho I could be wrong). No need to
explain it since I'm sure I can Google it if I really need to learn.
 
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Nick
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      08-01-2011, 10:07 AM

On Mon, 01 Aug 2011 00:17:29 -0500, in alt.sys.pc-clone.dell, "RnR"
<(E-Mail Removed)> wrote:

>On Sun, 31 Jul 2011 19:06:58 -0400, Ron Hardin
><(E-Mail Removed)> wrote:
>
>>Do any Dell laptops find themselves unable to power from a modified sine
>>wave UPS?
>>
>>No use springing for a sinewave UPS unless necessary.
>>

>If I recall correctly, this has already been discussed here and no
>need for special UPSs (anyone pls correct me if I'm wrong).


It depends on the power supply in the computer being hooked up to the UPS.

As I found out the hard way a year and a half ago, my XPS 9000/435T does
need a UPS with a sine wave output. Plugged into a UPS with a non-sine wave
output, my computer shuts down instantaneously when the UPS switches to
battery backup power.

No idea if any other models (desktop or laptop) are the same way.

> Aside
>from this, I still don't understand what a PowerFactor is and I recall
>having a part of a lecture one day in an Electrical Engineering
>college class going over it (I'm not an EE). I've also read about it
>in a usenet newsgroup and still didn't quite get it but I also gather
>it doesn't get used much my EEs (tho I could be wrong). No need to
>explain it since I'm sure I can Google it if I really need to learn.


Power factor is the phase angle between current and voltage in an AC
circuit.

In a pure resistive circuit, it's zero because the current and voltage are
exactly in phase. If there's unbalanced inductance or capacitance in the
circuit, then the power factor won't be zero because the voltage and current
won't be in phase.

--
Nick <(E-Mail Removed)>

"My mind is already made up. I do not want any facts,
as they would simply confuse me." M.E.
 
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RnR
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      08-01-2011, 11:07 AM
On Mon, 01 Aug 2011 06:07:03 -0400, Nick <(E-Mail Removed)> wrote:

>
>On Mon, 01 Aug 2011 00:17:29 -0500, in alt.sys.pc-clone.dell, "RnR"
><(E-Mail Removed)> wrote:
>
>>On Sun, 31 Jul 2011 19:06:58 -0400, Ron Hardin
>><(E-Mail Removed)> wrote:
>>
>>>Do any Dell laptops find themselves unable to power from a modified sine
>>>wave UPS?
>>>
>>>No use springing for a sinewave UPS unless necessary.
>>>

>>If I recall correctly, this has already been discussed here and no
>>need for special UPSs (anyone pls correct me if I'm wrong).

>
>It depends on the power supply in the computer being hooked up to the UPS.
>
>As I found out the hard way a year and a half ago, my XPS 9000/435T does
>need a UPS with a sine wave output. Plugged into a UPS with a non-sine wave
>output, my computer shuts down instantaneously when the UPS switches to
>battery backup power.
>
>No idea if any other models (desktop or laptop) are the same way.
>
>> Aside
>>from this, I still don't understand what a PowerFactor is and I recall
>>having a part of a lecture one day in an Electrical Engineering
>>college class going over it (I'm not an EE). I've also read about it
>>in a usenet newsgroup and still didn't quite get it but I also gather
>>it doesn't get used much my EEs (tho I could be wrong). No need to
>>explain it since I'm sure I can Google it if I really need to learn.

>
>Power factor is the phase angle between current and voltage in an AC
>circuit.
>
>In a pure resistive circuit, it's zero because the current and voltage are
>exactly in phase. If there's unbalanced inductance or capacitance in the
>circuit, then the power factor won't be zero because the voltage and current
>won't be in phase.



Thanks Nick for correcting me. Great explanation too !!
 
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Ron Hardin
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      08-01-2011, 12:46 PM
RnR wrote:
>
> On Mon, 01 Aug 2011 06:07:03 -0400, Nick <(E-Mail Removed)> wrote:
>
> >
> >On Mon, 01 Aug 2011 00:17:29 -0500, in alt.sys.pc-clone.dell, "RnR"
> ><(E-Mail Removed)> wrote:
> >
> >>On Sun, 31 Jul 2011 19:06:58 -0400, Ron Hardin
> >><(E-Mail Removed)> wrote:
> >>
> >>>Do any Dell laptops find themselves unable to power from a modified sine
> >>>wave UPS?
> >>>
> >>>No use springing for a sinewave UPS unless necessary.
> >>>
> >>If I recall correctly, this has already been discussed here and no
> >>need for special UPSs (anyone pls correct me if I'm wrong).

> >
> >It depends on the power supply in the computer being hooked up to the UPS.
> >
> >As I found out the hard way a year and a half ago, my XPS 9000/435T does
> >need a UPS with a sine wave output. Plugged into a UPS with a non-sine wave
> >output, my computer shuts down instantaneously when the UPS switches to
> >battery backup power.
> >
> >No idea if any other models (desktop or laptop) are the same way.
> >
> >> Aside
> >>from this, I still don't understand what a PowerFactor is and I recall
> >>having a part of a lecture one day in an Electrical Engineering
> >>college class going over it (I'm not an EE). I've also read about it
> >>in a usenet newsgroup and still didn't quite get it but I also gather
> >>it doesn't get used much my EEs (tho I could be wrong). No need to
> >>explain it since I'm sure I can Google it if I really need to learn.

> >
> >Power factor is the phase angle between current and voltage in an AC
> >circuit.
> >
> >In a pure resistive circuit, it's zero because the current and voltage are
> >exactly in phase. If there's unbalanced inductance or capacitance in the
> >circuit, then the power factor won't be zero because the voltage and current
> >won't be in phase.

>
> Thanks Nick for correcting me. Great explanation too !!


The apparent trouble is that the modified sine wave confuses the circuits in
PFC power supplies and they decide to shut down rather than deal with it.

The trouble is not in the modified sine wave itself but in faulty design of the
PFC supply.

The question is whether these supplies (that shut down) are used on laptops.

Some dell adapters claim to be PFC supplies but I don't know that they shut
down with a modified sine wave.
--
(E-Mail Removed)

On the internet, nobody knows you're a jerk.
 
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RnR
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      08-01-2011, 02:16 PM
On Mon, 01 Aug 2011 08:46:47 -0400, Ron Hardin
<(E-Mail Removed)> wrote:

>RnR wrote:
>>
>> On Mon, 01 Aug 2011 06:07:03 -0400, Nick <(E-Mail Removed)> wrote:
>>
>> >
>> >On Mon, 01 Aug 2011 00:17:29 -0500, in alt.sys.pc-clone.dell, "RnR"
>> ><(E-Mail Removed)> wrote:
>> >
>> >>On Sun, 31 Jul 2011 19:06:58 -0400, Ron Hardin
>> >><(E-Mail Removed)> wrote:
>> >>
>> >>>Do any Dell laptops find themselves unable to power from a modified sine
>> >>>wave UPS?
>> >>>
>> >>>No use springing for a sinewave UPS unless necessary.
>> >>>
>> >>If I recall correctly, this has already been discussed here and no
>> >>need for special UPSs (anyone pls correct me if I'm wrong).
>> >
>> >It depends on the power supply in the computer being hooked up to the UPS.
>> >
>> >As I found out the hard way a year and a half ago, my XPS 9000/435T does
>> >need a UPS with a sine wave output. Plugged into a UPS with a non-sine wave
>> >output, my computer shuts down instantaneously when the UPS switches to
>> >battery backup power.
>> >
>> >No idea if any other models (desktop or laptop) are the same way.
>> >
>> >> Aside
>> >>from this, I still don't understand what a PowerFactor is and I recall
>> >>having a part of a lecture one day in an Electrical Engineering
>> >>college class going over it (I'm not an EE). I've also read about it
>> >>in a usenet newsgroup and still didn't quite get it but I also gather
>> >>it doesn't get used much my EEs (tho I could be wrong). No need to
>> >>explain it since I'm sure I can Google it if I really need to learn.
>> >
>> >Power factor is the phase angle between current and voltage in an AC
>> >circuit.
>> >
>> >In a pure resistive circuit, it's zero because the current and voltage are
>> >exactly in phase. If there's unbalanced inductance or capacitance in the
>> >circuit, then the power factor won't be zero because the voltage and current
>> >won't be in phase.

>>
>> Thanks Nick for correcting me. Great explanation too !!

>
>The apparent trouble is that the modified sine wave confuses the circuits in
>PFC power supplies and they decide to shut down rather than deal with it.
>
>The trouble is not in the modified sine wave itself but in faulty design of the
>PFC supply.
>
>The question is whether these supplies (that shut down) are used on laptops.
>
>Some dell adapters claim to be PFC supplies but I don't know that they shut
>down with a modified sine wave.



Funny Ron, as I was writing the last post, I was wondering about
laptops too. I haven't heard of it but that doesn't mean anything. I
will let someone else more qualified answer this question. Also I
wonder besides Dell, if this question affects other brands too??
 
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Daddy
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Posts: n/a
 
      08-01-2011, 03:32 PM
Ron Hardin wrote:
> Do any Dell laptops find themselves unable to power from a modified sine
> wave UPS?
>
> No use springing for a sinewave UPS unless necessary.
>
> So far I haven't noticed laptops failing but I suppose one might secretly
> be on its own battery power and I didn't realize it.


Is there something about a laptop that makes it different from a desktop
w/r/t a sine wave UPS? If so, apologies in advance and ignore the rest
of this post.

I had a similar question when I purchased my desktop (Studio XPS 8100),
which also has a power factor correcting power supply. The problem was
that a pure sine wave UPS would have set me back roughly half the cost
of my computer.

I had deep suspicions about the need for a pure sw UPS, but I won't
repeat the long back-and-forth discussions I had about this topic.
Suffice it to say that, on paper, you need a pure sw UPS...but the real
world is much different. Try this test before you spend the next two
months eating sandwiches:

Pull the UPS' plug from the wall socket. Does your equipment still run?
Are you getting error messages? If the answers are yes and no,
respectively, then you're good to go without an expensive new UPS.

If you're using your laptop for some very critical purpose, you want to
spend the extra money, but then you're talking about a completely
different situation from the norm.

Daddy
 
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