power factor correction on laptop power supplies

[[email protected]]

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

Michael

 

[Eeyore]

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

 

[[email protected]]

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?)

Michael

 

[Phil Allison]

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

 

[Joerg]

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.

 

[Eeyore]

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

 

[Phil Allison]

"Joerg"

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

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.


...... Phil

 

[[email protected]]

Input power I think.



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

Graham

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

Thanks,

Michael

 

[[email protected]]

<[email protected]>





** 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?

Michael

 

[Phil Allison]

<[email protected]
"Phil Allison"

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

** Completely irrelevant reply.

Try again sometime, pal.



....... Phil

 

[Eeyore]

"Phil Allison" wtote.

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

Near as dammit.

Graham

 

[[email protected]]

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.

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

 

[[email protected]]

[email protected] wrote:

(snip)


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?

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.

Thanks,

Michael

 

[Joerg]

"Joerg"


** Not at all.

Just the usual rms to average ratio current of a rectifier and capacitor
filter - has a PF of about 0.5

A PF of 0.5 _is_ ghastly

** 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.

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.

 

[neon]

uderstand this. that is the inrush current only.

 

[Jasen Betts]

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

But if it doesn't it may be less than 75W input, and thefore not need
PFC...

Bye.
Jasen