Good link. Another clue is that domestic power bills (mine at the very least) are for = units of=20 power in kWh, which is real/true power. If power factor were part of the eq= uation=20 then I presume the units would be kVAh. Perhaps not entirely correct - from= my=20 student days I seem to recall being told that industrial electricity users = were charged=20 higher rates if their current usage went over set limits in peak times - he= nce the=20 benefit of power factor correction. An actual power factor correction device for a changing load (typical house= hold)=20 would need to make adjustments as load power factor varies - which seems no= t to=20 be the case with the power panda total saver if the diagram on their web si= te is=20 anything to go by. My favourite question fromt he auction site was this one: Q. you seem to have a lot of pictures of the stickers, are these what helps= stabilise=20 electrical currents?=20 Also on their web site is a device for saving power with electric hot water= heaters=20 (NZ$479). They say heater element turns on and off to maintain setpoint=20 temperature in cylinder - true. They say resistance of heater element is ne= ar zero at=20 switch on (not true) implying an inrush of current hence power savings are = possible=20 if this were controlled (therefore also not true). In reality there is no d= oubt the=20 resistance if the element will change with temperature by some percent, but= the nice=20 thing about a heater element is that being a predominantly resistive load p= ractically=20 all the electrical power you put into it is turned into heat, even if it's = more or less=20 than the nominal power rating of the element, that just heats the water whi= ch is what=20 it's supposed to do. Also, domestic hot water is typically (here) on a sepa= rate meter,=20 and likewise it is measured in kWh not kVAh so there is no room for power f= actor=20 arguments. As an aside - I recently upgraded my hot water cylinder. My old one had a 1= kW=20 element, the new larger cylinder came with a 3kW one. I checked the wiring = voltage=20 drop from element to switchboard with the 1kW element, and determined that = with=20 the 3kW element I would be looking at a 4% drop (5% allowed). That would ha= ve=20 been 120W I2R losses in the wiring (heating my house, not the water). I spl= it the=20 difference and used a 2kW element, about 50W loss which seemed more=20 acceptable. On 17 Jan 2011 at 11:22, William Couture wrote: > I asked about devices like this last January, and was pointed to this > excellent website by John Coppens > http://www.nlcpr.com/Deceptions1.php >=20 > Bill >=20 > On Mon, Jan 17, 2011 at 2:41 AM, RussellMc wrote: > > This device just sold on a NZ auction site for $600 (about $450 US) > > > > I put this in EE because the comments and discussion make the > > otherwise ludicrous snake oil claims worth thinking about. Doesn't > > stop them being snake oil, but worth being able to deal with them. > > > > =A0 =A0 =A0http://bit.ly/YRPandaPowerSaver > > > > Deep in the Q&A discussion are two interesting comments. I leave the > > examination of the validity of these as an exercise for the student: > > > > 1. Comment on power factor measurement by home meters > > 2. Comment on power factor of non-heating domestic load. > > > > ________ > > > > > > Copied here. > > See website for much more > > > > 1. > > > > Q: hey dont the meters on house measure true power? power factor > > correction unit like this correct apparent power and will not effect > > the reading of the meter. also most househols appliances have pfc > > built in theses days cbksmum (1653 ) =A07:24 pm, Mon 17 Jan > > > > A: =A0Hi, No the meters on the house do not. The meters just assume you > > have true power. It affects you because you use electricity. It's like > > a 98 car, you put 91 petrol into it, the car has to work harder, and > > you go through more fuel. You are absolutely 100% wrong about most > > household appliances having pfc built in. I'm sorry but this just > > bollocks > > > > 2. > > Q: =A0Hi. I understand your "waves" and "in sync" and you are on the > > dollar. And this being a power factor correction device/power > > conditioner I understand you will achieve 0.98 PF. (98 % efficency). > > What I don't understand is that the power factor of a house would be > > about 0.5 or 0.6 as you have quoted in %. Is this assuming everyone > > has 2 fridges and a deep freeze and a water pump to drag the PF down? > > jayydee (80 ) =A07:45 pm, Mon 17 Jan > > > > > > A: =A0Fridge + heatpump + washing machine + dryer + all the lighting in > > most houses does it. Even just lighting and fridge will do it in some > > properties. Our face to face agents in the field actually measure the > > power factor in the places they sell to. 0.5-0.6 is the most common > > range. > > > > > > _________________ > > > > See website above for much more in Q&A > > > > > > THEY CLAIM: > > > > This auction is for one Power Panda Total Saver. > > This is a residential Total Saver and will fit a house with one, two, > > or three meters. > > > > This fantastic device will see you save 15-40% on every Power Bill. > > This device works with most electrical equipment, fridges, freezers, > > anything that chills, washing machines, driers, anything with a motor, > > fluorescent lights, energy efficient lights, heat pumps, spa pools, > > water pumps, fans, computers, LCD screens, HD televisions. > > > > The only thing it doesn't make more efficient is electric hot water > > heating, and most heaters. > > > > How it works is that the electricity coming into your house is highly > > inefficient. Your electricity should be a set of smooth waves, but > > instead it's a disjointed mishmash. What the Total Power Saver does is > > to push this electricity into a smooth wave, a process that makes your > > electricity more efficient. > > > > The Total Saver achieves three main things > > 1) Conversion of electrical spikes into usable electricity. > > 2) Ensuring that the volts and the amps are in sync so your > > electricity is 98% usable. (Your house is probably about 50-70% usable > > currently) > > 3) Maintains voltage at 240V. (Your electricity is probably at a lower = voltage) > > > > This auction is for a cosmetically scratched Total Saver. It still > > works fantastically, but as it is scratched we are just selling this > > to get rid of it. We've paid for it, we can't sell it at full retail > > ($3500) so we may as well give somebody a bargain. We have tested the > > Power Panda Total Saver and it works fantastically. > > -- > > http://www.piclist.com PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > >=20 >=20 >=20 > --=20 > Psst...=A0 Hey, you... Buddy...=A0 Want a kitten?=A0 straycatblues.petfin= der.org >=20 > --=20 > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist >=20 --=20 Brent Brown, Electronic Design Solutions 16 English Street, St Andrews, Hamilton 3200, New Zealand Ph: +64 7 849 0069 Fax: +64 7 849 0071 Cell: +64 27 433 4069 eMail: brent.brown@clear.net.nz --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .