Would this really save electricity?

[T i m]

Understood, anything with a SMPSU for example.

Well yes, but my point was no matter how *hard* you boil the water it will still take the same time to cook the egg. ;-)

T i m

[T i m]

Indeed and your para above confirms my (and the TV presenters) point about using appliances at their design voltage.

Of course 'multi voltage' devices will cope so they don't really count in any case, it's the stuff being designed to run on a fixed 230 being run on 240 (as it is here right now) where I think they think there could be a saving.

T i m

[Harry Bloomfield]

T i m presented the following explanation :

Agreed, but other than incandescent lamps, there are not many (if any) other items which have an absolute design voltage or not able to work as efficiently at a range of voltages.

Such as? You buy lamp bulbs to match your supply voltage, so they should already be working at their best efficiency. Kettles simply need to run for less time to boil the water on the full voltage. Ovens similarly. None of your tech equipment cares about the voltage and will simply increase their current draw for the decrease in voltage, so what am I missing?

[s0lstice]

The interviewee is VPhase Chief Exec Dr Lee Juby; his parents had a sense of humour, or perhaps he was born in 1977.

[john jardine]

Looks like you're spot on.

a Triac feeding that buck winding. Their main worry (rightly!)seems to be overheating of the core. Myself, I wouldn't have one given.

[T i m]

Well, if you are going to exclude incandescent's I can't think of many specifics but I was playing devils advocate re the theory that '*some* savings could be made by using said product. Like, Our fridge and freezer are quite old and therefore probably wouldn't have the energy saving bits in them. The washing machine, and dishwasher have induction motor pumps that may be drawing more current than they need and kettles and toasters that *may* not be running as efficiently as designed (hearing the water less efficiently (too fast)) or burning the toast slightly more than it might at a lower voltage etc.

If you do, you didn't so who know how many other people have?

Of course, but you can't say they are as efficient (to the .001 of a %) until you did the tests. For any given thermal loss and energy transfer there would be an optimum heating rate. Too slow and thermal loss would overcome the heating effect and too fast would simply instantly boil the water around the element, possibly affecting the energy transfer.

Ovens would probably suffer less as they are generally thermostatic and the usage times are longer.

I agreed that one.

The spirit of my reply? ;-)

Did I mention I wasn't going to buy one.

T i m

[Harry Bloomfield]

..judging by the thermal trip.

I would guess they have based there figures on short term measurements of the reduction in current demand, rather than any longer term measurement of actual reduction in consumption.

All resistive loads will use less if the voltage is reduced (Ohms Law), but they will make up for it by running for increased periods to produce the same work output.

[Harry Bloomfield]

Harry Bloomfield explained on 30/07/2009 :

There is no stuff designed to be run on a fixed voltage any more, just check the specification pages of equipment. My electric razor will happily charge itself up on anything between 12v and 240v. My desktop PC will run on anything between 105v and 245v. The exceptions are old style lamp bulbs and heating elements, though the later usually have a little wider tolerance than lamps.

Older PC power supplies had a switch on the back to select 220/110 volt input. The fuse to protect the PSU at 110v was double the amperage rating of the 240v one, because as the voltage was reduced by 2 the current had to double to produce the same output to the PC.

The video mentioned many of these gadgets being installed in lots of commercial premises to good effect. I get around lots of these places and I have never seen one.

[Harry Bloomfield]

T i m was thinking very hard :

No :-)

[Harry Bloomfield]

True, but if they are that old then they were probably designed to work on 230 -250v. Reduce the voltage to 220v and your risk them not being able to start at all and burning out the motors.

Motors draw the current they need to do the work. Reduce the voltage and they draw more current to make up for the decreased voltage.

Due to the design of kettle elements almost all of the heat will be drawn out of the element by the water. If you watch the element when switched on from cold, there will be localised steam created on the element, until convection gets going, then steam bubbles created again around the element as it gets nearer actually boiling. The bubbles burst, imparting there heat into the water.

Pretty efficient already this trickery, once it gets to where it is to be used :-)

[john jardine]

Snake oil indeed. They would have every right to call it and sell it respectably as a 'mains voltage stabiliser'. Technical kit with perfectly valid applications in a number of areas. But they don't. They know there's only a small market and profit for this kind of gear, so they show themselves as disingenuous marketing scum by calling it a 'money saving device', tagging on the Green/Enviro' ticket and keeping their fingers crossed, hoping no one can look deeply into the somewhat arcane technical aspects. As per the Mony Python sketch ...'it makes me sooo mad'. (the newsgroups win out yet again! :)

[T i m]

Understood.

And there is no resistive 'loss' for that increased voltage and fixed load, ever?

So, what if the initial phase continued throughout the entire process, do we know it that would be more or less efficient? (I'm not suggesting such a minor change in voltage would have that effect btw).

As long as you remember to turn clockwork timer on your toaster down a tad and don't mind you toast done as the designer intended. ;-)

T i m

[dennis]

It is probably still true though. "Many" doesn't have a definition to tell you what percentage of premises have these devices so you can't know what the odds are of you seeing one. Many could be 10, 100, 1000,.. you just don't know. Its one of the weasel words used by marketing folk.

[Andrew Gabriel]

oooer...

Actually, it's not as clever as I guessed. I can think of better ways to do what they are aiming to do, but I'm not going to give them ideas for free (except unfortunately the one I already gave above;-), for them to go and try to patent!

Also, it's a surprisingly poorly produced patent, unnecessarily restricting it's scope to some of the poorer design decisions, which means it's likely someone else can fix those and patent a better design -- that's something you try to avoid when writing a patent. Maybe the better ways are already patented? (Perhaps I've been spoilt by having really good patent attorneys, who I could never afford if I was paying myself.;-)

OTOH, buck/boost regulators have been around for donkey's years and are commonplace in areas of the world with poor mains regulation. I'd be surprised if there's much this basic still left to patent, and wouldn't be surprised if much of this patent has already been covered by earlier patents and/or prior art.

Me neither. The principle of regulating voltage to save energy is broken from the off.

[Andrew Gabriel]

In general yes. However, domestic fridge and freezer motors are actually both designed and expected to fail to start on occations, and include the necessary protection and retry circuitry (even very old ones).

and become less efficient with more slip.

[dennis]

It is a requirement for a patent to be specific. If you try and make it too broad you wont be able to enforce it latter. You couldn't patent the idea of saving money by dropping the mains voltage for instance. You could patent the way of dropping the voltage unless its obvious like using a transformer.

I'm surprised how trivial some patents are.. like dyson putting cyclonic separators in household vacs and getting patents by copying existing technology.

[Dave Osborne]

Well, that's not true Harry. Anything with a transformer and a linear regulator is going to use less energy as the mains voltage falls right down to the point where the dropout voltage in the regulator is reached. The regulator will then shut down and your tech kit won't be using any current at all...

IOW Up to a point, for linear regulated power supplies, reduced mains voltage will reduce unnecessary heat dissipation (and more than likely prolong the life of the electrolytic caps to boot.)

[Harry Bloomfield]

Dave Osborne was thinking very hard :

Agreed, but I can't think of any item of equipment in this house which is in regular daily use, which still uses a linear regulated PSU. Even my phone charger is a SMPSU. I do of course have lots of test gear and lots of home built stuff which uses linear supplies, but these are not in what I would call regular domestic usage.

[Laurence Payne]

I once mistakenly plugged a stage amplifier into a dimmer-controlled circuit (why a stage lighting outlet was a 13 amp socket rather than a

15 amp is a whole other story of misunderstood building regulations).

It didn't quite let out smoke, but things were getting that way. The resident electrician explained it quite simply. The power supply had excellent regulation. As it couldn't get enough volts, it tried to take too many amps.

[T i m]

Much of our background 300W is just that, old linear_heavy_wall-wart type PSU's for all sorts of kit that is on 24/7, including 6 x DECT phone PSU's, 4 (of the 5) router / switch / APs, the electric curtain opener, portable DAB radio / recharger, a SCART to TV UHF modulator and (3) Kenwood PMR handset / cradles to name but a few. There is even a Nokia charger that seems to get left in quite a bit and that's for my 6310i. ;-)

T i m