Stupid Question

     OK, I'm not the electrical genius in the family, but it seems to me that
if this power factor business somehow means that power is flowing out of
your home and back to the power company =after= it has been through your
meter and you've been charged for it, how would you go about recovering it
from the cable?
    I may be intelligent, but in this area I am completely uneducated and
freely admit it.
    Jim

  Jim brought forth on stone tablets:

Not quite that, Jim.  Because of reactance in the load, the current and
the voltage are not tracking each other simultaneously.  For inductive
reactance (the usual case), the current lags 90 degrees behind the
voltage.  This means in turn that the power available in the load
(voltage x current) at any point along the waveform is less than what
you would assume if you just measured the average voltage and the
average current and then just multiplied them.

But the power company has to generate the current and use conductors big
enough to carry the current, and they have to use insulators suitable
for the voltage, so they charge you for the current x voltage, *not* for
the actual power used.  Correcting the power factor by adding the
opposite reactance - in the case of an inductive load, a capacitor is
used - brings the voltage and current back into phase with each other.
Thus, when you pay for average current x average voltage, you are
getting what you pay for.

bob
s/v Eolian
Seattle

 

In PECO/Exelonland, homeowners have no demand or power factor charges.
Businesses do, with a penalty if the average power factor is below 0.9.

Nick

 RW Salnick wrote:
...

Funny, around these parts they bill the average consumer on the
actual power used. Perhaps we've got better meters?

Anthony

 

    It seems to me that we do mangle the beautiful sinusoidal current we
use, but sending it back for free strikes a nerve....