power factor correction on laptop power supplies

Guest
Do typical modern power supplies for Dell, HP, Gateway, etc. laptops
employ power factor correction?

Michael
 
mrdarrett@gmail.com wrote:

Do typical modern power supplies for Dell, HP, Gateway, etc. laptops
employ power factor correction?
Click to expand...
In Europe if they are rated at > 75W they have to.

Graham
 
mrdarrett@gmail.com wrote:
On Aug 4, 4:16 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:
mrdarr...@gmail.com wrote:
Do typical modern power supplies for Dell, HP, Gateway, etc. laptops
employ power factor correction?
In Europe if they are rated at > 75W they have to.

Graham


75W output, right?

The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)
Click to expand...
It's higher, just means that the power factor must be quite ghastly.
While a good meter may measure 1.6A input current a watt meter won't
measure as high as 160W.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
 
Joerg wrote:
mrdarrett@gmail.com wrote:
On Aug 4, 4:16 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:
mrdarr...@gmail.com wrote:
Do typical modern power supplies for Dell, HP, Gateway, etc. laptops
employ power factor correction?
In Europe if they are rated at > 75W they have to.

Graham


75W output, right?

The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)


It's higher, just means that the power factor must be quite ghastly.
While a good meter may measure 1.6A input current a watt meter won't
measure as high as 160W.

Or the 1.6A input rating is conservative, to handle inrush or just on
Click to expand...
general principles.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
On Aug 4, 4:16 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
mrdarr...@gmail.com wrote:
Do typical modern power supplies for Dell, HP, Gateway, etc. laptops
employ power factor correction?

In Europe if they are rated at > 75W they have to.

Graham
Click to expand...

75W output, right?

The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)

Michael
 
mrdarrett@gmail.com wrote:

On Aug 4, 4:16 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:
mrdarr...@gmail.com wrote:
Do typical modern power supplies for Dell, HP, Gateway, etc. laptops
employ power factor correction?

In Europe if they are rated at > 75W they have to.

Graham

75W output, right?
Click to expand...
Input power I think.


The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)
Click to expand...
Possibly a fault condition rating ? Odd though. It would get damn hot.

Graham
 
mrdarrett@gmail.com wrote:

"Phil Allison" wtote.

The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)

** So you are still bamboozled by the difference between VA and watts.

..... Phil

If the device employs power factor correction, the difference between
VA and Watts goes to zero, right?
Click to expand...
Near as dammit.

Graham
 
On Aug 4, 7:04 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
mrdarr...@gmail.com wrote:
On Aug 4, 4:16 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:
mrdarr...@gmail.com wrote:
Do typical modern power supplies for Dell, HP, Gateway, etc. laptops
employ power factor correction?

In Europe if they are rated at > 75W they have to.

Graham

75W output, right?

Input power I think.

The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)

Possibly a fault condition rating ? Odd though. It would get damn hot.

Graham
Click to expand...

Gets very warm to the touch when charging the battery. After it's
charged, it's quite cool.

Thanks,

Michael
 
On Aug 4, 4:59 pm, "Phil Allison" <philalli...@tpg.com.au> wrote:
mrdarr...@gmail.com



The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)

** So you are still bamboozled by the difference between VA and watts.

..... Phil
Click to expand...

If the device employs power factor correction, the difference between
VA and Watts goes to zero, right?

Michael
 
mrdarrett@gmail.com wrote:

If the device employs power factor correction, the difference between
VA and Watts goes to zero, right?
Click to expand...
If it employed perfect power factor correction, it would.
If it employs practical power factor correction, it gets
close enough. In this case, I don't know what the legal
definition of "close enough" is.

--
Regards,

John Popelish
 
On Aug 5, 5:24 am, John Popelish <jpopel...@rica.net> wrote:
mrdarr...@gmail.com wrote:
If the device employs power factor correction, the difference between
VA and Watts goes to zero, right?

If it employed perfect power factor correction, it would.
If it employs practical power factor correction, it gets
close enough. In this case, I don't know what the legal
definition of "close enough" is.
Click to expand...

Yep, nothing in life is perfect... same goes for heat exchangers,
electric motors, GAC contactors...

So, if I'm understanding this correctly, I'm paying more money for
electricity (and introducing some noise into the grid) if I don't
implement PFC?

Michael
 
mrdarrett@gmail.com wrote:
(snip)
So, if I'm understanding this correctly, I'm paying more money for
electricity (and introducing some noise into the grid) if I don't
implement PFC?
Click to expand...
You are not paying anything extra for that power factor
current if you are an ordinary residential customer in the
U.S.A.

You are wasting a little bit of power (that you are not
paying for) in the power distribution system, and generating
some harmonic distortion in the line waveform.

--
Regards,

John Popelish
 
mrdarrett@gmail.com wrote:
On Aug 5, 3:41 pm, John Popelish <jpopel...@rica.net> wrote:
mrdarr...@gmail.com wrote:

(snip)

So, if I'm understanding this correctly, I'm paying more money for
electricity (and introducing some noise into the grid) if I don't
implement PFC?
You are not paying anything extra for that power factor
current if you are an ordinary residential customer in the
U.S.A.


Ah, so industrial customers pay extra for not implementing PFC?
Click to expand...
Some do see a separate charge for power factor current. But
we all pay in the end for inefficiencies of power
distribution with a higher price for real power. If most
devices included power factor correction, the actual cost of
delivering power gets down and the system delivery capacity
goes up, Somebody gets that savings.

--
Regards,

John Popelish
 
Phil Allison wrote:
"Joerg"
mrdarrett@gmail.com wrote:
The one I'm looking at right now says 100-240V @ 1.6A input (160W
in?), and 65W output (19V @ 3.42A)

(Are they really only 40% efficient?)

It's higher, just means that the power factor must be quite ghastly.


** Not at all.

Just the usual rms to average ratio current of a rectifier and capacitor
filter - has a PF of about 0.5
Click to expand...
A PF of 0.5 _is_ ghastly :)

While a good meter may measure 1.6A input current a watt meter won't
measure as high as 160W.

** Often, the amp draw rating refers to the size of the AC fuse.

Eg, my PC monitor is rated at 240 volts and 2 amps, but in fact draws only
0.6 amps rms and 56 watts.
Click to expand...
Yeah, could be. Other times they state the max right after turn-on, when
the degausser is busy and other stuff spools up. If yours is a CRT
monitor then 56W is pretty decent.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
 
On Aug 5, 3:41 pm, John Popelish <jpopel...@rica.net> wrote:
mrdarr...@gmail.com wrote:

(snip)

So, if I'm understanding this correctly, I'm paying more money for
electricity (and introducing some noise into the grid) if I don't
implement PFC?

You are not paying anything extra for that power factor
current if you are an ordinary residential customer in the
U.S.A.
Click to expand...

Ah, so industrial customers pay extra for not implementing PFC?


You are wasting a little bit of power (that you are not
paying for) in the power distribution system, and generating
some harmonic distortion in the line waveform.

--
Regards,

John Popelish
Click to expand...

Thanks,

Michael
 
On 2008-08-05, mrdarrett@gmail.com <mrdarrett@gmail.com> wrote:
If the device employs power factor correction, the difference between
VA and Watts goes to zero, right?
Click to expand...
But if it doesn't it may be less than 75W input, and thefore not need
PFC...

Bye.
Jasen
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top