voltage Optimiser - A Load Of Bull?!?!

[VMan]

Hi Guys,
Just reading through my spam and got an email for a voltage optimiser - claiming to save you money by reducing the voltage!!!

MyPlanet Voltis Voltage Optimiser

To me this is bull, if something need 1kW to work then it will consume 1kW..no?

My Math example:

At 240 volts:

1000watt appliance = 240 volts x 4.16Amps (240 / 4.16 = 57.7ohms)

My said appliance is heating a said volume of water and needs 1kw to boil. i.e 1000Watts for one hour

------------------------------

if i put a voltage reducer to 218V

At 218 Volts:
( V/R = I ) 218 / 57 = 3.77Amps

(P = I x V) 3.77 x 218 = 821.86 watts - ok customer maybe convinced and may buy one.


Now my said appliance still needs to boil the same amount of water, and will need the same amount of energy.

So 1 hour of the appliance on will only heat the water to 82% of needed value. there for will need to be on a total of 73mins to heat said water (deliver 1kW of energy to the water) - well maybe a bit more due to heat losses whilst heating the water.?!?!

so 1 Kwh will still be 1kWh regardless of voltage?!?!?

Am I right or wrong? or can anyone else explain how this may work -

(I believe a kW meter does not record Power factor(where a k/VA meter will) so even the power factor bull isn't right here.)

cheers

 

[plugsandsparks]

I did look at the Vphase units seriously, they were being promoted at a NAPIT conference and that is how i heard of them. What was clear is that they are not design to do anything other than drop the output volts and realistically the VA they can handle is limited even for a domestic. As already mentioned anything that is a heating load is automatically ruled out so this limits the installation to the lighting ccts and sockets in some parts of the house as there is some energy savings due to reduced losses in PSUs that are scattered around the house. I was interested in it for a client that was enduring a supply voltage of 250+ and his bulbs were blowing weekly / daily. In the end i converted them to a combination of low voltage and fluorescent.
Personally i cannot see them adding much value

 

[UNG]

BBC’s watchdog filmed some one doing just that. An empty patress box with a blank plate and a bit of 1.5 T+E vanishing in to the CU. It wasn’t even connected to anything.

What savings did they make or was that the problem

 

[Des 56]

If you installed an empty box it would be interesting to see what savings where claimed as there is obviously some placebo effect with these units

Well done ung, he has finally cracked the technology behind the infamous V phase :39:

 

[Knobhead]

They are based on multi tapped auto-transformers with solid state switching. Any transformer will have inherent losses. As the load increases the higher the losses. It then reaches the point where it goes in to bypass. Even at minimal load you can’t escape the transformer losses.

Many years ago I did an experiment on a large scale. Four 20MVA 33/11KV transformers with on load tap changers. Over several weeks I lowered the voltage available the plants. Voltage went down, current went up.
1KW = 1KW no matter what you do to it.