Measuring power dhs at
Wed Apr 29 12:05:21 BST 2009

On Apr 29 2009, Chris Benson wrote:

[ ... ]

>I have a similar meter from Efergy at home and once spent a frustrating
>weekend trying to get it to agree with the official meter.
>Eventually I realised that these meters are measuring VA, not W.  The same
>for resistive loads, but considerably different for inductive loads such
>as CFL and electric motors.   I have one "32W" CFL that draws 67VA.

Indeed: one of those "simplifications" they make in teaching O-level 
(sorry, GCSE) physics (that dates me... :-)

>Of course VA maybe what you want.

Probably: that's what the power company bills you for...


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