I’m back home. Thanks to everyone who helped while I was offline with family medical issues. There are larger challenges ahead but for now things are back to near normal. Thanks to everyone who left kind words in the announcements thread – I feel like Jimmy Stewart at the end of “It’s a Wonderful Life”.
One thing I always like to do on trips south is to visit Fry’s electronics. There, I can take in the full measure of what’s new in the electronics world. While there, I picked up a gadget that solves an ongoing problem in my home. This is worth a read if you want to save money on your power bill.
While some of my incendiary foes like Joe Romm would like to make you believe that I’m anti-everything (his favorite word is “anti-science” when describing anyone who doesn’t agree with him), those of you who read WUWT know that I’m proactively energy efficient. For example, earlier this year I wrote about installing super efficient LED recessed lighting in my home. I’ve yet to see Joe Romm write a single positive thing about what he is doing personally to practice what he preaches.
I recently went through a home energy audit related to my recent Smartmeter installation (which is another story all by itself) and one of the things I decided I needed to do something about was the growing number of vampire power suckers in my home. As we added more technology, the number of always on power sucking wall-warts (120vAC to 12Vdc power transformers) increased.
Until now, there wasn’t any really practical way of dealing with them all, so I thought I’d share this solution since I’m sure many of you have similar problems with vampire power.
First some background. Here’s a video on vampire power from iGo:
Defining the problem:
Lawrence Berkeley National Laboratory has a whole website dedicated to standby power issues and offers this assessment:
An individual product draws relatively little standby power (see here for examples) but a typical American home has forty products constantly drawing power. Together these amount to almost 10% of residential electricity use.
That 10% for me is an issue, because on hot summer days when we need a/c the most, that standby power baseline adds to our allowed PG&E baseline use, and when we go over it, our electricity costs escalate rapidly. PG&E actually punishes residences who consume over the allowed 445 kwh baseline in tiers, such that by the time you exceed 200% of baseline, your cost per kwh is now at 40 cents per kWh, which is outrageous.
Unfortunately, PG&E is a monopoly, and the Public Utilities Commission in California actually approved this outrageous rate hike for over baseline use while simultaneously dropping the allowed residential baseline from 512 kWh/month to 445 kWh/month in the last year. It was a major blunder, and this is why Smartmeters have been getting such a bad rap. PG&E chose the worst possible time to start, in May. Combine new rates, smartmeter swaps, and summer temperatures and you get a PR disaster and people up in arms.
Here in the Sacramento valley, we have temperatures here that reach 110 degrees at times, requiring a/c use. My only option now with these new rates is to reduce energy use. Now that’s something I don’t mind doing, I’ve been proactive at it, but I must say I feel discriminated against compared to Californians who live on the more temperature coast, because I already live in an energy star rated newer (4 years) home. They don’t have a/c issues like we do in the central valley.
So in a nutshell, I’m hosed by my location and its summer climate. That’s why my July 2010 energy bill was $620.16 (electric, plus gas, plus loads of taxes and other taxes – like “public purpose programs”, part of which supports climate change research in California) last month for 2052 kWh of use. If it were at regular baseline rate the bill would be half that. So anything I can do to get closer to baseline will be helpful.
Measuring the problem:
I went around my home with an LCD meter called the Kill-a-Watt EZ and determined that I have 3 areas of significant vampire power use that could benefit from a makeover.
These can be ordered from Amazon for about $30 plus shipping and are dirt simple to use. They can show you instantly how much standby power is being drawn on any appliance or power strip. There’s also a graphing version and a power strip version.
While I had all sorts of spots all over the house, I identified three areas where phantom power was concentrated and working to kill the vampires would be a worthwhile effort.
- My computer workstation where I manage WUWT and research
- My wife’s computer workstation with central printer
- Our entertainment center and TV (#1 draw)
All of these had a collection of wall-warts for network switches, speakers, USB hubs, amplifiers, and accessories. The main devices like the TV, DVD player, DVD reorder, satellite box, all had “instant on” features and drew a fair amount of load and most of these were on 24/7. Just looking at them in infrared shows where that power was going:
So not only are they wasting electricity, they are dumping waste heat into the house 24/7, adding load to the air conditioning.
According to this interactive page at Lawrence Berkeley National Laboratory, I had all the vampire family members. My own readings from the Kill-a-Watt meter were right in line with these:
What was the biggest surprise to me was how much standby power my set-top satellite receiver boxes were drawing. I have a newer model and older model from DirecTV. The older model was drawing 31 watts in standby! Again right in line with what LBL says:
You can see the LBL master list of appliance tests for standby power draw here.
Finding a solution:
One way to solve phantom power draw is with power strips. I already use these to corral wall-warts, and when we go on trips I make it a point to reach behind the computer, under the desk, and behind the TV to shut these off.
However, doing that every night is a bit of a pain, and often forgotten in my house. So, the little suckers live through the night and during the day when we aren’t home.
So while a switched power strip *does* solve the problem in principle, it doesn’t in practice due to access. The strips are all behind and/or below something.
I had been toying with the idea of making some sort of remote switch for my power strips so I could easily turn them off when I shut down my PC, or turn off the TV and go to bed. Fortunately, I found a solution at Fry’s yesterday that did just that.
A way cool plug-in gadget that kills power vampires:
I was really happy to find this power strip gadget at Fry’s:
Apparently this was introduced at CES in 2008, but this is the first time I’ve seen it. It pays to advertise I suppose.
In case it isn’t obvious, this is a power strip with a wireless remote switch. The switch can be handled like a TV remote or wall mounted, making it easy to remember to kill the vampire when you turn out the lights to leave the room.
The remote has a range of 60 feet and can be set for 8 different channels so you can have multiple outlet strips in the home. Here’s some features:
Here’s the manual (PDF)
Installation was quick and easy for me, I just daisy chained from my existing power strip and chose which devices to plug in to “always on” and which to put into the “switched” outlets. See below:
Of course I had to make two wall-wart exceptions: answering machine and my home weather station (which has a data logger and automatically updates a web page). Now that I have it working and can easily kill off most of my office vampires, I’m planning on buying two more for the other locations that have heavy wall wart populations.
I highly recommend this product. Amazon.com has the best deal on the base model at $34.99 and there are other models which you can see here. There are also UK/European and Australian power outlet versions I’ve found.
While we might disagree on climate change, saving money by reducing energy use is something I think we can all agree on.
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Even if the total for your entire hours is 200W, this amounts to a kWh every 5 hours, or 144kWh/month. Let’s assume you install switches and turn this draw off for 8 hours a night, this will cut the vampire consumption a third, saving your 48kWhs, or about $20/month at the highest rate.
I mean it’s not chump change, but it’s marginally worth the inconvenience – and my cable box doesn’t like to be sans power. It forgets everything and has to re-download the cable guide.
One theory has it that the number of lives lost due to 230 volt electrocutions is balanced by the number lost in fires caused by overheated wiring and socket connections in the high current draw 115 volt systems. One might attribute the early and effective setting up of the Underwriters Lab to the 115 volt system.
Japan is an interesting case study for the 115/230 volt debate. Initially when electric lighting and appliances were introduced to Japan, each town purchased its own generating plant, way before talk of a grid. The company that repped AEG sold European 230 v 50 Hz plant, and the company that repped Westinghouse sold 115 volt 60 Hz. This patchwork was a nightmare when trying to centralize generation for economy of scale, and it was not until just before WW II that the government, or the military if there was a distinction at that time, grasped the nettle and set a standard. Of course it is not polite to tell half the population that they are wrong, so the compromise was to make the standard an even, neutral, 100 volts. That is why you will often see a 100 volt tap on some Japanese equipment transformer primaries. The 50/60 Hz question was harder to solve, and when I last looked, a while ago, the country was still fairly evenly divided. This gave their manufacturing industry a great start in exporting, as they were already making their products line frequency compatible, or at least available for both.
When it came to setting TV standards, US and UK/European “experts” claimed that a 625/50 system would be incompatible with 60 Hz power, and a 525/60 incompatible with 50 Hz power, based on their own experience. The Japanese proved that if you made your TV set to a good engineering standard, keeping the power line fields where they belonged, there was no compatibility problem. Which gave them another “unfair” advantage when they started exporting to the rest of the world. Putting enough iron in the power transformers helped.
Anthony, am glad you are back and hope your family medical issues were successfully resolved. You have motivated me to do an energy audit of my house.
I would like to comment on 2 home energy issues not discusses above (unless it missed it in the comments). First: I didn’t see ceiling fans in the . I have 6 along with remote control modules. We do forget to turn them off when we go to bed. Second: I am fortunate enough to live in an area where heat pumps are effective. Last winter I found out the expensive way that if you set them more than 2 deg (?) warmer than the room temperature they automatically kick on the emergency heating strip. See page 4 of this .
When measuring power draw with the kill-a watt, be sure to look at the “VA” (volts * amps) power, not the Watts. You pay for the VA. Check out the standby draw of a typical UPS in VA, I have one that shows about 15 Watts in standby, but about 80 VA. The power factor on modern electronics is horrible!
Apparantly I screwed up the HTML tags. My previous should read
Anthony, am glad you are back and hope your family medical issues were successfully resolved.
I would like to comment on 2 home energy issues not discusses. First: I didn’t see ceiling fans in http://standby.lbl.gov/summary-chart.html. I have 6 along with remote control modules. We do forget to turn them off when we go to bed. Second: I am fortunate enough to live in an area where heat pumps are effective. Last winter I found out the expensive way that if you set them more than 2 deg (?) warmer than the room temperature they automatically kick on the emergency heating strip. See page 4 of http://www.sdge.com/documents/forms/heatpumps.pdf.
Brewster,
Ohm’s Law: Volts X Amps = Watts. So VA = Watts.
$620 electric bill!!!! No wonder California is going down the toilet, but like they say, so goes California, so goes the country. I have a fit when our electric bill approaches $100!
Wow! The extent some feel compelled to go in order to save a few dollars is mind boggling, but after reading Anthony’s electric bill, just WOW! It’s hard to believe we still live in America. Now energy is a political tool to force us to lower our standard of living to satisfy a small minority of environmental kooks bent on controlling our lives, not to mention money for politicians to waste.
Geothermal is the way to go; that’s what we did. Total cost for heating/cooling/hot water? Under $500 per year in Northern Michigan.
Anthony since you indicated you have a substantial A/C load, here are a few tips.
Measure the attic temperature. Look and see if you have radiant barrier insulation installed. Here in SC one vendor indicated it had become a code requirement in California. If you don’t have it go get it! Vendors can install enough for the typical house for $3000. You can buy the material for $300 and do it yourself (it is pretty easy). You can expect a 20% decrease in A/C load just from this stuff. It also helps out in the winter as well. While you are at it check and see if you have a thermostatically controlled attic exhaust fan. The style here in SC is to use the Eave/Ridge vent system which doesn’t work real well. The last thing you might consider is a roof irrigation system. After a rain you will find that attic temps will fall 20 deg F or more. You can thermostatically control that if you are really ambitious. Just a few tips but the idea is to decrease the load on your A/C. You could also install Solar assisted DHW which will pay for itself in about 5 years.
There’s another huge power-hog out there that isn’t very amenable (at least as yet) to individual saving measures: single-phase electric motors.
In actual fact there’s no such thing. A mechanical crank is metastable — the slightest move off dead center produces a moment that makes it keep going. Your car engine’s crankshaft is an example. The electromagnetic equivalent is stable — a push off dead center produces a moment that returns it to center. An electric motor therefore requires at least two out-of-phase magnetic fields to turn at all.
Motors that apparently run on single phase have internal means of creating the second phase. In old-fashioned DC motors it’s the commutator. “Brushless” DC motors are actually AC induction motors containing electronics that convert DC to polyphase AC. Small, cheap AC motors are “shaded pole”, in which a shorted winding produces the second phase. Larger motors use combinations of capacitors and inductance, usually special windings within the motor, to accomplish the same thing. All of those methods have something in common: they waste power. A shaded pole motor can dissipate as much as a third of its input power in heat generated by the shorted winding. Medium-sized motors have to have switches (“starters”) to provide an extreme phase shift at startup and change over to a lesser shift at speed, because running with full shift all the time would melt the motor but the amount of phase shift while running isn’t enough to start the load. Big motors have to be fed polyphase power from outside, because they can’t economically be built to dissipate the heat generated by the phase shifting mechanism; that effect becomes notable somewhere around half a horsepower/400W. Motors up to two HP/1500W with internal phase converters are available, but they are bigger, heavier, and more expensive than they need to be, both to dissipate the heat created by the phase shifter and because the phase shift mechanism uses capacitors rather than inductance, which is more efficient but bigger, bulkier, and more expensive, besides being notoriously a point of failure, as are the switches that shift from “start” to “run” mode.
Another pernicious effect of “single phase” motors is feedback into the distribution system. The phase shifter is across the input lines, and its effect is to reduce the “power factor”, which is the voltage-current relationship. Reduced power factor makes everything draw more power than it should, even resistance heaters. The effect is magnified because induction motors are inherently synchronous, meaning that the feedback push from all of them adds rather than being distributed randomly. Factories and shops that use a lot of motors aren’t allowed to run on single-phase because of that effect, because the power-factor shift would affect everyone negatively.
Go through your house and add up the power draw of all the small motors. Most of them are air-movers of one type or another, fridge fans and HVAC air distribution and condenser blowers (combined in window AC units), but washing machine and dryer motors are mostly shaded-pole because it’s cheap, and window AC units use shaded-pole compressor motors for the same reason. Roughly a quarter of that power, somewhere between a fifth and a third, is wasted in the motors’ internal phase shifters; you also pay for, but don’t get the use of, another 1-2% of your total bill because your meter actually measures current, and the power factor shift increases current draw without increasing actual power usage. The electric company isn’t cheating you with that, either, because the generating distribution system has to have expensive (and power-wasting) means of correcting the problem at their end. That effort is harder and more expensive than it might be here in the United States, because local distribution is “delta” rather than “wye”; the power-factor imbalance causes circulating current in the transformers, which wastes heat to the atmosphere before the energy can ever be used.
A total changeover from internal-shift to polyphase-fed motors could save as much as a third of the total power used by motors; the estimates I’ve seen are that this would amount to between 5% and 10% of total power usage. Unfortunately the capital cost of the change would be enormous — it would mean rewiring every home and small office on the planet and replacing almost every motor-driven appliance, and just smelting the copper to do that would eat up all the energy savings in at least a five-year period.
Modern electronics might come to the rescue. The fans in computers and electronic gear used to be shaded pole; they have almost all now gone to polyphase induction with transistor-based phase converters (the so-called “brushless DC” motor). Machine shops and other users of medium to large motors are rapidly changing over to electronic phase converters that rectify incoming single phase to DC and create a polyphase output; the conversion is more efficient than the motors’ internal phase converters, and as a bonus the converters can also vary the frequency, giving variable speed without complicated (and power-robbing) gears and belts. At present such converters are too expensive for use in most appliances, but I’ve already seen one high-end refrigerator that uses brushless-DC fan motors to meet “energy star” requirements, and one can hope that it is only a matter of time before advances in engineering and economies of scale bring those advantages to HVAC units, washing machines, and dryer blowers, all of which could benefit not only from the power saving in bulk polyphase generation but from the ability to run at variable speed without mechanical arrangements that cost money, rob power, and require maintenance.
Regards,
Ric
Interesting find,
I know of a builder in Washington State,who deliberately build in shut off switches in the walls where you would find the light switch.It would shut down any outlets in the house.
He showed in a “Green” home he built in the Ellensburg area a few years ago. He was very aware of such low level power consumption,even when the units appear to be “off”.
He showed me a meter showing the changes as he turned the units off totally.When he got all of the units off,the meter went to zero.
Some builders are aware of it and are incorporating methods to zero the power leaks.
I have been shutting off the power source to my two working computers,because all those shining little lights bugs me when I sleep.I like deep darkness where I then feel restful.
We still have a long way to go because homes are still poorly designed to reduce energy loss and the absurd waste of street lighting where there are little traffic in them.
What will it take to wake up America,to the solutions of saving money and increase their independence?
If the “problem” is defined as incremental increases in power useage, why would California encourage illegal immigration?
Each person who slips across the border uses many times what you, with your out-of-pocket expense, save. The State has supposed shortages of electricity, jobs, housing, water, schools, jails and freeways which it simultaneously exacerbates with its unacknowledged policies.
All at your expense, and if you mention it, you’re a bad person.
Paul ZZ says:
September 6, 2010 at 4:38 am
It may be worth going to the root of the problem – the Air Conditioning is using too much power, and having a go at this.
http://mb-soft.com/solar/saving.html
____________________________________________________
Looks interesting. Have you tried it?
I am always worried that this type of stuff is an expensive scam. I am in NC (62F ground temp) and our A/C bill is about $300 so it sure could be useful.
My other big electric user is the well water to water our animals. Ponds are a possibility except for the wild life carried diseases -mosquitoes (Eastern Equine Encephalitis ), Opossums (Equine protozoal myeloencephalitis), or beaver (Giardiasis )
Also at this point I hate to go to the trouble and expense of making ponds now only to have to fill them in as the farmers are being required to do in California. See: http://articles.sfgate.com/2009-07-13/news/17218619_1_food-safety-cookie-dough-food-borne.
I am considering the other option, a wind mill, a large storage tank and gravity feed on one of my wells.
I have to keep an eye on future regulations before I make any improvements and pray I do not have to rip it all out and do it over because of some %$#$ government inspector’s whim.
I also believe in room power switch outlets. When the room switch is off, the lights and all the outlets in that room are turned off. Easy to install and no extra gadgets required. I live in a way old ranch house that when wired for electricity, there was only one switch that turned the entire room on and off, including all the plug ins (which were typically hanging from the light or at most, only one on the wall for everything).
This tech has been around for a decade or more. It is called X10. A slicker solution is to buy some x10 outlets. http://www.activehomepro.com/accessories/pro/pao11_wa1_s.html and put a remote by your bed that you can turn everything off when you go to bed. Or even cooler buy this. http://www.x10.com/automation/firecracker.htm and use http://www.lickey.com/flipit/ to write a linux web interface for everything. You could then set up a schedule using crontab. I have done all of this and only takes a small amount of technical know how. One work of warning, the X10 does draw a very small current to work and will shorten the life of CFL bulbs.
$68 in June and up to 90 in July. We use electric stove and bake very little in the summer. We also wash dishes but have an electric clothes dryer. We do not turn on a tv every month. Electric rates in the prairie seem lower.
Glad you’re back Anthony. Hope things improve or go easier on you in future.
These tech notes for energy saving are great!
PS: The biggest problem people have with technology is keeping up with it.
AND, and… the older people get the farther they seem to fall behind the pack.
I bought a 3-outlet remote (RF) monitoring set from a gadget shop around the beginning of this year. There are 3 sensors that plug into outlets and a wireless display/counter. Very handy if you’re wondering how much it’s costing to watch TV, etc..
The outlet meter into which I’ve plugged all my computers, etc. shows 1182 kWh consumed over 2860 hours. Very little of that is standby power. Quiescent, the stuff draws about 360W. I turn off the “desktop” computer if I’m away for more than a couple of days but the server and firewall are on all the time.
OTOH, when I’m using the colour laser printer to print, it drinks heavily from the wire; drawing over 1 kW. But that’s for 30 seconds a day on average.
The outlet meter into which I’ve plugged my TV, Hi-Fi, etc has recorded 195 kWh over 2883 hours. The standby power, when I’m not away for more than a couple of days, runs at 21 watts. There are about 20 devices plugged in, but only 8 draw “standby”. One is a network switch (always on) to slurp media from the net through the Digital TV PVR/STB, Blue-Ray DVD which shows AccuWeather (and other stuff), or the DAB receiver which can also play streaming media.
Most of the equipment that I have in the house which has a “standby” mode consumes less than 3W on standby. Much of it consumes less than 1W.
I waste more energy having to leave CFL lights on so that I can see what I’m doing when I walk into a room. When I had proper light bulbs, I’d switch on the light when I entered aroom, and switch the light off when I left. Now it seems that I leave the kitchen light on for 6 to 10 hours a day, instead of the hour or so that I actually need it.
While renovating the bathroom, I put in a motion sensor and (now) LED lights, for both convenience and to save money on electricity. The motion sensor uses less than 1W. The LED lights had better last 10 years to pay for themselves.
The US has missed that train, therefore they are stuck with their ridiculously thick dryer-cables, and their flimsy 110V-plugs.
Um…no, we’re not. As stated elsewhere on this thread, US clothes dryers (and air conditioners, and cookstoves, and everything else that pulls a large amount of power) operate at 240V. Power in the US enters the home as two 120V lines, 180 degrees out of phase, and a neutral line which is tied to ground. The breaker box is designed to make it easy to send either 120V or 240V wherever you want it. Kind of like the best of both worlds.
I just installed a 50A subpanel in my garage that includes a 240V breaker for an oven (for powder coating small automobile parts) and a host of 15A to 30A 12oV outlets. Very easy to do. Everything is current-limited at the breaker box (twice, for the subpanel…once at the subpanel and once at the main breaker box).
The US power system may be different than in Europe and elsewhere, but it works extremely well.
Smokey: VA are NOT watts when you talk about AC circuits. Has to do with power factor. If volts and amps are in phase, like DC, then yes. But usually not. So you draw more amps and VA’s (OK, VAs) And pay for it. Even if the power company tells you they charge for kWh’s.
Here in southern CO, my electric bill runs about $45/mo. Of that $25 is Customer Service Charge, for the honor of being connected to the utility. $20/mo of actual electricity. I have a handful of these vampires, no where near 40. And hard to imaging much savings if I turned them off. $2/mo? Long payoff time.
As for the 120/240 debate (there is no 115, 117, 110), 120 is less likely to kill you than 240. 480 will throw you across the room, 240 will not. 120 takes more copper. And, after my travels in France and the U.K., electricical safety codes on the east side of the pond are a joke. Which is not to say ours are a lot better. Conduit is the only sane way to wire a house. Romex is a disaster waiting to happen. Build a Colorado style house near Chicago and go to jail.
My 8 year old desktop, router, network disk drive, and fairly new LCD monitor use about 80w according to my power monitor (and display on the UPS). A notebook would take less, but not near as much fun. Big displays are nice. Full size keyboards, separate numeric keypads. And a real mouse instead of that @ur momisugly#$% touchpad.
I’ll pay the $20.
Anthony,
You and the good people of California are getting RIPPED OFF!
My August bill came in at $465.07.
$109.96 for the off-peak rate at $0.053/Kwh
$79.06 for the mid-peak rate of $0.080/Kwh for anything over 2074.75 Kwh
$76.61 for the on-peak rate of $0.099/Kwh for anything over 2074.75+988.31 Kwh
Delivery charges: $89.26
Regulatory charges: $26.64
Debt retirement: $25.94
HST tax: $53.50
Non-electricity charges represent almost 40% of my electricity bill. But I pay less than half the rate of Californians. No wonder the State is bankrupt. You can’t afford your electricity bills!
Come on up to Canada. You’ll freeze your a$$ off, but you’ll save money with every shiver!
Steamboat Jack says:
September 6, 2010 at 6:56 am
” get the Californians to move to Texas……………..”
I think that, if you do the aritmetic, all the people in the world 6.7 billion [approx]could fit into Texas and have about 1000 square feet of space each.
NO?
Lots of room it seems. 😉
Texas is big
a jones says:
September 5, 2010 at 10:59 pm
“Here I pay flat rate at 10p, say 15 US cents, day or night per KWh and in any quantity I choose up to my maximum supply rating which is 30 kilowatts.”
The UK doesn’t have the air conditioning loads the US has.
As a result, in the US we have a number of power plants that only run a few months a year.
Power plants cost the same to build and maintain whether they are running 24/7 or just a few days a year. Hence, many utilities have a ‘peak load’ surcharge that reflects the cost of building and maintaining ‘low utilization’ power plants.
Alexej Buergin says:
September 6, 2010 at 3:10 am
” inversesquare says:
September 6, 2010 at 1:06 am
The main advantage of this system is that nothing in the system is at a higher potential than 115 Volts relative to ground. This simple safety advantage has saved countless lives compared to 230 Volt systems.”
So that is why people all over the world are dropping like flies? Can you show us a statistic about that? Were there more electrocuted folks when Europe changed to 220V?
(And they did not have the modern security devices then, that automatically shut off the power. And yes, 220V feel exactely like 110V.)
I think you’ll find that I didn’t say that….. It was someone else;)
This item is also available in Canada at Best Buy and Staples.
Brewster says:
September 6, 2010 at 7:05 am
I don’t believe that’s true, I think it is watts you pay for. Industrial users have more complicated rate scales with peak demand and power factor components.
The spinning disk meters electromechanically multiply the instantaneous voltage and current, whereas “VA” (or “apparent power”) is computed by multiplying the RMS voltage by the RMS current. That’s important in things like UPSes, which is why they are rated by KVA. (RMS is root mean square – the square root of the average of the square of the voltage/current/whatever. RMS voltage makes sense since resistive loads draw current proportionate to the voltage, so watts = voltage² / resistance.
AFAIK, power factor computations go back to phase angle offsets thanks to things like electric motors and other inductive loads. They feature points where the voltage is positive, but the current is negative. Solid state switching power supplies that try to extract a steady power wind up drawing more current in the low voltage part of the cycle, and less at the high voltage parts. A very different beast, but has some similar issues for power distribution and generation.
There probably should be two separate definitions for power factor.
Smokey says:
September 6, 2010 at 7:13 am
No, Ohm’s Law is Amps X Resistance = Voltage. That’s the primary reason resistance is measured in ohms.
Apparently no one ever was honored with a law for Volts X Amps = Watts, it’s generally just called the power equation. Perhaps I’ll start calling it Anthony’s Law.