On Fri, 05 Oct 2007 17:17:00 -0700, wrote:

On 5 Oct, 23:51, Rumble wrote:
wrote:

snip

When you measure the power factor, are you measuring it for the device
in question, or are you measuring the average for the neighbourhood?
A plug-in device can only measure it for the load running through it.

Are you suggesting it somehow compensates for the power factor of the
supply automatically?

T

Is this a trick question? The supply doesn't have a power factor; only
the load has a power factor.

It wasn't supposed to be a trick question. The supply has a power
factor by definition. The question is whether it equals unity or not.
Are you implying that a domestic supply is guaranteed to have a power
factor of 1?

T



?????

Not so!

The numerical power factor eg 1, 0.9 etc - is a measure of the phase
angle between the LOAD current and the applied voltage. It is also the
measurement of the ratio of real power and apparent power or the ratio
of watts (W) to voltamperes (VA).

Look at Google:

http://www.google.co.uk/search?hl=en...ition&ct=title


The power companies worry about the overall power factor of the supply
for obvious reasons.