cfl's , poor Power Factor and your power meter

With all the fuss over powerfactor correction (or lack of) with CFL lamps and with some cfls with poor powerfactor (like 0.4) the actual power usage can be double the stated Watt rating. I didn't really care as my powermeter measures Kilowatts , ie its not a VA meter but doing a little more reasearch I realise we are paying for the poor power factor. What a scam!

Take a look at your power meter; I think it measures apparent power thought its actually called KWH meter that is contradictory to one another KVAH meter is apparent power while KWH is real power, if you look upon the construction of the meter itself it acts like a simple induction motor running both is current and in voltage, the line current is usually the total current you use in your household, P=VA , this is actually the formula for apparent power in an AC circuits, because P=VA X power factor is the formula for real power in AC circuits and I don't see any provisions of power factor reading in the KWH meter that makes me conclude that indeed the meter used in our homes measures apparent power not real power. :) though it states KWH meter on the nameplate.

Reply to
tuppy
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"tuppy the troll "

** Inrush surge is a FAR bigger issue with CFLs than the distorted current wave issue.
** Utter BOLLOCKS !!

The stated power consumption in watts for CFLs IS the REAL power consumption.

** More BOLLOCKS.

Domestic power meters ARE watt meters.

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** Totally false.

..... Phil

Reply to
Phil Allison

From Wiki

Electromechanical meters The most common type of electricity meter is the Thomson or electromechanical induction watt-hour meter, invented by Elihu Thomson in 1888. The electromechanical induction meter operates by counting the evolutions of an aluminium disc which is made to rotate at a speed proportional to the power. The number of revolutions is thus proportional to the energy usage. It consumes a small amount of power, typically around 2 watts. The metallic disc is acted upon by two coils. One coil is connected in such a way that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic flux in proportion to the current. The field of the voltage coil is delayed by 90 degrees using a lag coil. [1]This produces eddy currents in the disc and the effect is such that a force is exerted on the disc in proportion to the product of the instantaneous current and voltage. A permanent magnet exerts an opposing force proportional to the speed of rotation of the disc - this acts as a brake which causes the disc to stop spinning when power stops being drawn rather than allowing it to spin faster and faster. This causes the disc to rotate at a speed proportional to the power being used.

From me

So the meter has two coils, one for voltage and one for current. Try putting some big inductors or capacitors on your circuit as a load, what does the power meter do?

Reply to
Davo

Fundamental misunderstanding of physics. The VA usage (apparent power) may be higher but NOT the actual power.

Graham

Reply to
Eeyore

On Thu, 9 Apr 2009 17:27:30 -0700 (PDT), tuppy put finger to keyboard and composed:

From Energy Australia:

=================================================================== ... most residential classification customers are metered by a spinning disc meter, or a basic electronic meter which does not have enough "smarts" in the meter device to enable billing to be carried out at a KVA pricing.

Currently small customers are billed on KWh pricing, and KVA Demand pricing usually relates to large commercial and industrial installations where poor power factor may impact upon the EA network ... ===================================================================

- Franc Zabkar

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Reply to
Franc Zabkar

thanks Franc,

looks like I dont have to worry about paying for powerfactor.

thanks again for good answer.

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Reply to
tuppy

That part is phrased interestingly - does it mean that if we get "non-basic" electronic meters, that they'll start KVA pricing?

I think I remember hearing that we're all going to get new electronic meters in Victoria in the medium term. I wonder what type of meters?

Peter

Reply to
Pete

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