On 18/04/14 22:45, Uncle Peter wrote:
On Fri, 18 Apr 2014 12:48:36 +0100, Daniel
wrote:

On 17/04/14 23:46, Uncle Peter wrote:
On Thu, 17 Apr 2014 13:50:32 +0100, Daniel
wrote:

On 17/04/14 10:07, Uncle Peter wrote:
Can someone confirm that power factor is NOT taken into consideration
for domestic supplies? I have a feeling it isn't, but I can't find
any
information on the internet. If it matters, it's a modern (5 years
old) electronic meter I have. The power factor in my house is an
average of 0.7 so depending if it's charged for or not, my bill
could be
completely different.

When I last dealt with this, power generator companies "assumed" there
would be an average power factor and set up their generators to handle
that. Your individual house (or, probably, even a small factory) would
not cause much variation in that power factor, considering the
generators are probably supplying hundreds of thousands of homes at the
same time!!

That won't apply to switched mode power supplies clipping off the peaks
though.

Wouldn't cause a very big blip in the grander scheme of things.

And what SMPS clips off the peaks?? Usually they vary the switch on
point in the A.C. waveform.

You can get power supplies with "active PFC" which is presumably what
you just described. However the cheap ones have "passive PFC" or no
PFC, so presumably they just top up the bulk capacitors at the peak of
each waveform. A basic transformer and rectifier will do the same.

What's "PFC" when it's at home?? Power Factor Correction maybe!!

To the mains supply, most things look like Inductors, which means the
voltage waveform and the current waveforms are not in phase. Power
Factor Correction simple means that capacitors are switched in to
counter-act the Inductance, so the Voltage and Current are more nearly
in phase.

Active PFC might be changing how a transistor "appears" (more capacitive
or less capacitive) to fix the phase angle.

And, as I typed earlier, your little power supply would have very little
effect on the phase angle of your homes mains supply!!

Now, when your refrigerator's (inductive) motor switches on, now that
might have a noticeably affect, but, in the greater scheme of your
regional Power companies operations, zero effect!!

Daniel