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Amilkar
November 29th, 2007, 11:56 PST
The "Operation Manual" (actually a single sheet, one side) for the Kill-A-Watt Power Meter reads as follows:

"The watt/VA key is a toggle function key...The LCD will display Watts as the active power, where VA is the apparent Power..."

When I try to measure the power consumption of my small freezer and I select, for example, "Watts", the P4400 reads "64". Now, if I select "VA" it reads "90". Which is the right reading? How many watts is the freezer really consuming.
Can anyone tell me the difference between "real watts" and "apparent Power"?

Thanks.

crewzer
November 29th, 2007, 12:51 PST
Amilkar,

Your fridge is drawing 64 W of power, or “real watts”. The “apparent power” is the mathematical product of line voltage and current, and does not take into account “power factor”, or the time delay between the voltage and current cycles.

You can read all about “power factor”, “real power” and “apparent power” in this Wikipedia article: http://en.wikipedia.org/wiki/Power_factor (http://en.wikipedia.org/wiki/Power_factor)

HTH,
Jim / crewzer

Amilkar
November 29th, 2007, 12:53 PST
Crewzer:

Thanks.
Once again I am in debt.

mike95490
November 29th, 2007, 13:07 PST
What's the story on the Kill-A-Watt's relating to mod-sine inverters - are they now usable with them, or still strictly "sine wave" only? Which does NAWS stock ?