Voltage optimisers

I think mine has a 1/8 hp compressor, and it seems to take ~90W when running, so not much sign of anything being saved (mind you it's only A rated not A+++++++++ or whatever rating they're up to now)

Reply to
Andy Burns
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That was a 6% drop. Perhaps the other 4% kicks in at maximum rated load when leakage inductance and transformer winding resistance volt drop take their toll?

It sounds to me like it's a basic, if BFO[1], autotransformer. It also sounds like it's intended to be installed between the meter and CU to reduce the whole house supply, presumably to compensate for a PSU line voltage that's consistently on the high side of the nominal 240v used in the UK.

If it included automatic voltage adjustment to compensate for variations in supply voltage, it would make sense. If it's just an autotransformer, prewired to provide a fixed 10% reduction as your post implies, it doesn't make much sense since the proper solution is to complain to your PSU about the overvoltage and arrange for them to adjust the supply back to the nominal 240v.

However, 251v is within the +10% upper limit for a notional (harmonised)

230v supply upon which all domestic kit, excluding incandescent lamps, is optimised. If the supply never exceeds 253vac using an accurate voltmeter, then it's within tolerance and unless the supply regularly exceeds this, quite frankly, I can't really see the point of inserting such a BFO autotransformer between the meter and the CU.

If this has been installed in the mistaken belief that it will reduce electrical consumption by household appliances, as almost everyone else has pointed out, it won't. Indeed the additional losses, even if quite tiny, will increase consumption negating any small gain made with incandescent lamps which will become noticeably dimmer, yet at the same time may last twice as long as normal (so, not all bad news if you don't minder the dimmer look).

If the average line voltage is above nominal, the 10% reduction shouldn't be a problem to white goods appliances which use electric motors, especially if they're modern 'Harmonised' appliances. However, too little voltage can cause motors to overheat and burn out, especially during startup surges with compressor loads such as fridges and freezers and, to a lesser extent, washing machine drum motors.

Kit that uses smpsus such as TV sets, desktop computers and the like, will automatically draw exactly the same power, typically over a supply voltage that ranges from a low of 186vac to a high of 265vac. Some of this kit may, like universal mains voltage laptop chargers and other battery chargers, function over the range of 90vac to the 265vac limit, drawing pretty much an almost constant power level according to demand from their electronic loads.

Most appliances that rely on heating elements for their function will simply use a longer duty cycle controlled by a thermostat. So, again, no net saving in energy consumption there. Even electric kettles will simply take longer to boil before their anti-boil dry sensor conveniently switches the kettle off as a kindness to the user. The more protracted heating up time will allow a little more heat to escape increasing the energy consumption slightly as it will in the case of every other appliance that uses energy for heating.

In short, if this "Voltage Optimiser" has been sold to your customer on the basis of reducing electrical consumption, then it has been sold as a "Snake Oil Solution" to a non-existent problem.

[1] Assuming a 10% drop on a 250v 100A supply, you'd need a 2.5KVA rated autotransformer which would weigh in, afaicr, at around 25 to 30Kg which in a domestic installation is one Big Fuck Off autotransformer! :-)
Reply to
Johnny B Good

The phone battery was dead or I would have taken photos.

Basically (my guess) it's just a toroidal with 3 tap offs. Not sure what it weighed but it was impossible for me to hold it to the wall with one hand to mark out the fixing holes.

I don't think that money is a problem for this customer and I doubt that he is after a 10% electricity saving (brand new HSE Discovery for the wife to take the kids to school etc [1]). He asked for it fitting, we do not suggest them, that is probably why this is the first one I have ever fitted.

My other guess is that he has read that it could make appliances last longer and I know that he was aware that he has 250V to the house. I tested it when his washing machine and iron blew up on the same day a couple of months ago - although neither of them blowing up were related to the incoming voltage.

[1] And a full set of brand new alloy wheels with winter tyres.
Reply to
ARW

10%? Check out photonic induction's youtube vid overvolting kettles. ISTR he got one upto about 10kW.

NT

Reply to
tabbypurr

Wow! These scam merchants put Russ Andrews to shame!

Interestingly, they're using the upper 'harmonised' tolerance limit of the UK 240v supply specification to scare their marks into buying this 'Snake Oil Solution'.

As per any advertising 'blurb' they're careful not to make any definite savings claims, using weasel words like "could" in place of "will". Also, they've been careful with their choice of appliances to avoid anything that automatically draws the same power regardless of mains voltage over voltage ranges well in excess of the widest of mains supply tolerances (no desktop PCs or laptops running off their charging brick) as well as anything with a thermostat (other than for the dishwasher (full cycle) where it's quite telling that this demonstrates the least savings).

It's been said that "Advertising" is the art of lying by omission. Boy, do these bastards advertise through their teeth!

Reply to
Johnny B Good

Oddly enough they also had input into this

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Reply to
ARW

Twin 6ft T8, is that not supposed to be 140W? Hairdrier, takes longer to dry your hair? Vacuum cleaner, more runs to get the cat hairs up:-) Microwave? Well that like a quicky in the pub toilets, all done in 3 minutes and everything is hot and steamy. Infra red patio heater, put a jumper on Fridge, no one is sure about that but mine works OK on 253V Dishwasher, surely most of the energy is in heating the water so FA saving

Reply to
ARW

I saw a similar device that purported to save significant energy by power factor correction. Bollix of course.

Reply to
harry

ARW was thinking very hard :

I don't think anyone has mentioned, that lowering the voltage/increasing the current, will produce more waste heat in the internal wiring of the building. It will not be much extra waste heat, but...

Reply to
Harry Bloomfield

To be honest, I was sceptical as well. Just what is the point. I mean if you have a very touchy device, then some kind of transformer will sort it, and actually most touchy devices seem to work quite adequately on the end of a surge protector and mains filter socket bar from Maplin, with or without the pretty window. :-)

Brian

Reply to
Brian Gaff

That was what I thought. Do people not learn this simple fact at school any moor, or could I go into business selling perpetual motion machines?

Brian

Reply to
Brian Gaff

Lowering the incoming voltage will not increase the current on resistive loads.

Reply to
ARW

Now if it were a gadget to fool the electricity meter into thinking you were not drawing as much power that is a whole other subject to do with power factor and phase shifts. Brian

Reply to
Brian Gaff

Plus where you have a relatively fixed voltage drop - like a bridge rectifier in an SMPSU, the losses will increase: more current through that bridge for smaller power output.

All in all it is complete bollocks - only thing that will mayybe impriove is incandescmet bulb life - who uses those?

And the transformer itself is probably only 95% eff...

Reply to
The Natural Philosopher

ARW has brought this to us :

True, but it will for all of the none resistive loads.

Reply to
Harry Bloomfield

Thats not what he said

If you need to draw the same power at lower voltage, you will draw more current.

That will mean extra losses in the wiring.

The key is the 'same power'

Many things will automatically compensate for a lower voltahege by drawing more current.

All SMPSUS for a start.

Some regulated motors. - a synchronous motor will draw what it has to to match the load at synchronous output speed.

Reply to
The Natural Philosopher

i.e anything with explicit or implicit feedback to stabilise the outpout power levels

Reply to
The Natural Philosopher

I would say that the resistive loads are the ones that use the most power. So hair driers, cookers, kettles, immersion heaters etc.

I only fitted the thing because the customer wanted it. I am happy with my 253V supply:-)

Reply to
ARW

When I was regularly running my electric car (from ~30 years ago now), if you got into conversation with people about it (generally men) it surprised me how many basically tried to suggest I could make use of perpetual motion.

Anything from having a dynamo rubbing on a tyre to towing a dynamo trailer to a wind turbine sticking out of the top.

Similar with running an electric boat and then 'having a paddle wheel hanging out the side connected to a dynamo ...'?

All of these would have been ruled out in an instant if they had even the most basic understanding of energy, energy transfer and conservation.

Also the way the electrical energy was used is a factor. My EV was only 48V and to move any conventional 4 seater vehicle through the air and along the road (on the flat) at say 30mph would take quite a bit of energy. I think my car was pulling something like 200A in those circumstances and so the interconnecting cables had to be pretty big (and therefore also heavy).

Cheers, T i m

Reply to
T i m

As an exercise in the art of propaganda (aka, advertising) this is a work of 'creative writing' even Joseph Goebbels would have been proud to sign his name to.

Reply to
Johnny B Good

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