Power Conversion Electronics

[Phil Allison]

"kony"


** No man is an island ......




..... Phil

 

[Michael A. Terrell]

kony wrote:

Which cage are you in, I will stop by and throw you a
peanut. And some lithium.

Throw him some Dilitium. His mind needs a recharge. ;-)




--
You can't have a sense of humor, if you have no sense!

 

[UCLAN]

Phil Allison wrote:

** This arrogant IMBECILE is about to get a lesson !!!

I suggest you do a little reading. Start with:

http://www.fairchildsemi.com/an/AN/AN-42047.pdf

Until then, I suggest you get back on your meds - quickly.

 

[CBFalconer]

John Larkin wrote:

"Phil Allison" <philallison@tpg.com.au> wrote:

.... snip ...

** TOTAL BOLLOCKS !!!

They are not capacitive, there is no phase angle.

Active PFCs correct WAVEFORM distortion.

Take you meds and lie down for a while. What he said was
perfectly reasonable.

Also, kindly give a complete description about how you determine
that an isolated waveform is distorted?

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

 

[CBFalconer]

Phil Allison wrote:

"John Larkin"

.... snip ...

Take you meds and lie down for a while.

** Drop dead.

What he said was perfectly reasonable.

** It was totally FALSE , you insane fuckhead.

I suspect he failed to follow your advice, above. It doesn't
appear to have improved his language, either.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

 

[Phil Allison]

"UCLAN" = Monkey's Uncle


** This arrogant IMBECILE has had his lesson.

But he didn't learn anything -

cos he is a congenital fuckwit.




....... Phil

 

[Franc Zabkar]

On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN <invalid@invalid.com> put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]

As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.

PA could easily put at end to this argument by enlightening everyone
with his own example ...

http://groups.google.com/group/aus.electronics/msg/fe5b24eacbfeb277?dmode=source&hl=en

.... but instead he chooses to elevate himself by demeaning others.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Eeyore]

Franc Zabkar wrote:

On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN <invalid@invalid.com> put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]

As much as I dislike the man, he's right.

He is. Actually, from modelling, I've found a big hulky inductor between the rectifier and
storage caps is pretty good at correcting harmonics. Trouble is, they're big, heavy and
expensive.

Sadly active PFC produces even more RF 'hash' that needs to be dealt with.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.

PA could easily put at end to this argument by enlightening everyone
with his own example ...

http://groups.google.com/group/aus.electronics/msg/fe5b24eacbfeb277?dmode=source&hl=en

... but instead he chooses to elevate himself by demeaning others.

Sadly so.

Graham

 

[Sylvia Else]

Franc Zabkar wrote:

On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN <invalid@invalid.com> put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]

As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.

It does show that the current leads - look at how it's not positioned
symmetrically about the 90 degree point, for example. It's not a 90
degree lead, of course, but it's still a lead.

Mind you, I think the graph is wrong. When it's flowing, the current
into a capactor should be proportional to the rate of change of voltage.
So you should see a rapid rise once the input voltage goes above that
already on the capacitor, followed by a progressive reduction towards
zero (plus the load current) at the voltage peak. I suppose you'd get
something closer to what's shown if there were an inductor in series
with the supply.

Sylvia.

 

[Franc Zabkar]

On Wed, 29 Apr 2009 12:28:36 +1000, Sylvia Else
<sylvia@not.at.this.address> put finger to keyboard and composed:

Franc Zabkar wrote:
On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN <invalid@invalid.com> put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]

As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.

It does show that the current leads - look at how it's not positioned
symmetrically about the 90 degree point, for example. It's not a 90
degree lead, of course, but it's still a lead.

A bigger capacitor would result in less ripple, which means less lead.
If you were relying on intuition alone, you would expect that the PF
would move closer to unity. In fact the PF actually becomes worse.

See the calculations in Phil's example.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

 

[Sylvia Else]

Franc Zabkar wrote:

On Wed, 29 Apr 2009 12:28:36 +1000, Sylvia Else
sylvia@not.at.this.address> put finger to keyboard and composed:

Franc Zabkar wrote:
On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN <invalid@invalid.com> put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]
As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.
It does show that the current leads - look at how it's not positioned
symmetrically about the 90 degree point, for example. It's not a 90
degree lead, of course, but it's still a lead.

A bigger capacitor would result in less ripple, which means less lead.
If you were relying on intuition alone, you would expect that the PF
would move closer to unity.

In fact the PF actually becomes worse.

With a larger capacitor, you get less lead, but higher instantaneous
currents. My intuition would be that the net result is far from obvious.

However, the higher current for shorter periods means higher harmonic
currents, which don't contribute to the power, so it wouldn't surprise
me that the PF would go down.

Sylvia.