Here comes the Power Perfector! What this "amazing" device does is drop your mains voltage down to the lower limit of the spec to "save" you energy...

I'm surprised that they don't claim that it'll make your CDs and MP3s sound better by 20% as well

Well, for devices with simple resistive loads, like light bulbs, this will indeed save power. For something like a computer, the power supply will just pull more amps.

It's going to be losing power from having to drop the voltage down to 210V as well though. I doubt the amount saved on your light bulbs and electric heating elements is significantly greater if at all than that lost in the unit.

Seems to be pretty genuine, for companies with a lot of equipment that will benefit it appears to produce good results. They have a case study listing Tesco and Woolworths who reduced consumption by quite a lot. Obviously "saving" power is not quite accurate since it will only be effective in certain ways.

However I am not convinced that the average house would make a massive saving - for instance the major useage of power in out house is probably washing, drying, cooking, televisions and computers. I don't think any of these would benefit. For lighting we use compact flourescent lamps for most rooms which are already very efficient, presumably the only effect would be a slight dimming, and if I wanted to save energy I would swap it with a lower powered version!

Gareth

Hmm. Good point. If it's in an industrial or commercial situation then it's possible that they've got huge numbers of incandescent lamps and motors which would make a difference when all added up.

It seems it's just a transformer. Look at the data log on this page:

http://www.powerperfector.com/perfector.php?src=perf10

It's not stabilising the voltage any, it just lowers it. They even use the word "tap".

These things are common in the States. We call them "Buck/Boost" transformers. It seems from their ad that overvoltage conditions are common. Not here. We always use the transformer in boost mode to bring undervoltage up.

Inductive loads become less efficient at lower voltages, and not linearly. I've never had cause to consider if they become inefficient at higher voltages.

I'm actually off to a meeting tomorrow morning to try and convince a developer that running his 220volt air conditioners on the 197volt supply is not a great idea. The local power company says that 197 is ok by them.

Over the life of my current UPS the supply voltage has varied between 207.3 and 260.6, though it does normally hover around 240. It very rarely registers and under voltage condition, there are typically one or two over voltage events a day.

The UPS output, on my APC at least, comes set to 246.2V in the UK.