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#1
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How does an electric meter work?
I did not check this out on snopes but have heard that the eletric
meters on our houses always read the higher of the two lines coming in to determine the amount of juice used. The rumor goes on that you should *balance* your panel so that the same number of constant users are on either side of your panel. An example might be that your fridge should be on one side and your furnace on the other, or electric range on one side and electric dryer on the other. Is there any truth to this or is it one of those tall tales based on some obscure Tesla theory? Would this gadget really save me money on my electric bill? http://www.renaissance-pacific.net/E...oduct_Info.pdf |
#2
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How does an electric meter work?
the only thing this does is bring more money to the merchant.
Yes both sides of the power line should be balanced, but BOTH items must be on at the same time. So the neutral doesnt carry current. SAVE YOUR MONEY! |
#3
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How does an electric meter work?
Wow.
I actually read that whole PDF just now. It's kind of interesting. Other than not explaining in technical terms, looking silly, and having a lame brochure, it actually doesn't make any wild claims like I would have expected. It makes a claim of 3-5% reduction. It specifically says it doesn't work for digital meters, and it is not a magnet, and it won't cause inductive heating problems. It mentions a handfull of other caveats too even. Since when does a scam make such modest claims and have so many caveats? What is the world coming to? Will I start getting "Enlarge your ***** by 3%!", or "Lose 1 to 3 lbs and keep it off as long as you keep exercising and maintaining a healthy diet!" emails? So can anyone answer the op's original question? Does a mechanical meter overestimate when the load is imbalanced? And if so, can anyone think of a plausible scenario, in any possible situation, real or imaginary, that would let the device in the PDF picture (I can't tell what it is -- just some kind of metal C-shaped thing I guess) do anything that could even have a remotely possible chance of having even a miniscule, undetectable, insignificant but still non-zero effect on the meter? I.e., is this just a not-very-useful and very poorly marketed invention, or a not very useful and poorly hyped scam? -Kevin |
#4
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How does an electric meter work?
I would look into power factor correction first.
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#6
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How does an electric meter work?
"Beachcomber" wrote in message ... On 24 Apr 2006 09:58:46 -0700, wrote: I would look into power factor correction first. Are you sure you want to mess with your power company based on some dubious claim from some website that this is "legal"? The Power Companies take theft of service very seriously and rest assured that if you device does what it claims to do, you could set yourself up for serious problems. At the very least, they can afford better lawyers then you. Power correction factor is different. It can be done inside, after the meter and is perfectly legal. I don't know if it is a viable option for residential, but for industrial use, there are savings to be had. |
#7
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How does an electric meter work?
I have wondered why certain appliances (espically washers and dryers)
didn't already have power factor correction already built in. |
#8
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How does an electric meter work?
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#9
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How does an electric meter work?
On 24 Apr 2006 06:59:12 -0700, "RayV" wrote:
I did not check this out on snopes Try doing so. That claim doesn't make sense. but have heard that the eletric meters on our houses always read the higher of the two lines coming in to determine the amount of juice used. The rumor goes on that you should *balance* your panel so that the same number of constant users are on either side of your panel. An example might be that your fridge should be on one side and your furnace on the other, or electric range on one side and electric dryer on the other. 240V appliances are always on both sides. They have 2 hot wires, 1 connected to each side. Is there any truth to this or is it one of those tall tales based on some obscure Tesla theory? Would this gadget really save me money on my electric bill? http://www.renaissance-pacific.net/E...oduct_Info.pdf Sounds like BS. |
#11
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How does an electric meter work?
My understanding is that large, commercial, installations
such as factories, supermarkets, refrigerated warehouses etc. use capacitor banks to adjust the power factor of their motors. In fact, power companies also have capacitor banks installed alongside the street, beside switches, to adjust the "average" power factor of loads to neighborhoods. On the individual scale, where a commercial consumer has a meter that measures amperes against time, that can be a benefit to both the consumer and the power company. The average homeowner has a meter that's called a VAR meter- Volt Amp Reactive. The cumulative power factor of the home's A/C, fan motor, refrigerator etc. are not measured by the meter and even a professionally calibrated and installed capacitor bank would make no difference in the 'Kilowatt Hours" consumed each month. To take advantage of this, the consumer would have to install a meter such as found in commercial installations. On some home-type of installations, such as an A/C compressor, pump, air compressor or possibly a refrigerator, a run capacitor to correct the power factor of the individual motor might benefit from a longer life or cooler operation, but it would be minimal and not seen on the electric bill. I'm sure that there are some engineers out there who can correct what I've written or expand on it. I'd sure like to learn more about this. Mark |
#12
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How does an electric meter work?
On Mon, 24 Apr 2006 18:22:10 GMT, "Edwin Pawlowski"
wrote: "Beachcomber" wrote in message ... On 24 Apr 2006 09:58:46 -0700, wrote: I would look into power factor correction first. Are you sure you want to mess with your power company based on some dubious claim from some website that this is "legal"? The Power Companies take theft of service very seriously and rest assured that if you device does what it claims to do, you could set yourself up for serious problems. At the very least, they can afford better lawyers then you. Power correction factor is different. It can be done inside, after the meter and is perfectly legal. I don't know if it is a viable option for residential, but for industrial use, there are savings to be had. Residential Meters do not measure for lagging or leading power factor. I've never heard of a utility charging a residence for low power factor. If this is true, there is no economic justification for making corrections to the power factor. Hence... I do not understand why you made the statement above: "I would look into power factor correction first" Beachcomber |
#13
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How does an electric meter work?
On Mon, 24 Apr 2006 16:51:21 -0500, unknown
wrote: On 24 Apr 2006 06:59:12 -0700, "RayV" wrote: I did not check this out on snopes Try doing so. That claim doesn't make sense. but have heard that the eletric meters on our houses always read the higher of the two lines coming in to determine the amount of juice used. The rumor goes on that you should *balance* your panel so that the same number of constant users are on either side of your panel. An example might be that your fridge should be on one side and your furnace on the other, or electric range on one side and electric dryer on the other. 240V appliances are always on both sides. They have 2 hot wires, 1 connected to each side. Is there any truth to this or is it one of those tall tales based on some obscure Tesla theory? Would this gadget really save me money on my electric bill? http://www.renaissance-pacific.net/E...oduct_Info.pdf Sounds like BS. Not only that, there is no explanation as to how this thing works that conforms to the known laws of physics. Any little piece of material that you wrap around your service entrance conductors is going to have little if any effect on "equalizing" the load between the hot wires. It is the current flowing that creates the magnetic field. Beachcomber |
#14
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How does an electric meter work?
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#16
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How does an electric meter work?
Thanks for answering (partially) my question. This thread is
interesting -- it seems to be filled with more BS and hype than the original link even was. I don't entirely understand your answer, though. I wasn't aware that there was a "neutral on the utility's side of the meter". And if there were, and I had a perfectly balanced load, then the neutral would have no current, right? Which means... no losses, and hence no cost? Obviously wrong... can you explain a little more? And moreover, there was a lot of BS in this thread about balancing the panel to begin with. To say that 240V devices are on both legs is irrelevant to the question of whether balancing a panel makes economic sense for the homeowner. Does a homeowner with a horribly imbalanced panel get charged more than the same homeowner if they just rearranged the breakers on the panel? -Kevin |
#17
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How does an electric meter work?
Dan Lanciani wrote:
In article .com, (kevin) writes: | So can anyone answer the op's original question? Does a mechanical | meter overestimate when the load is imbalanced? Yes, in the sense that the typical 4-terminal (1.5 element) meter most often used in residential split-phase service charges the customer for 150% of the losses in the neutral on the utility's side of the meter. (That's the simple case of one service drop from transformer to customer. For multiple connections the analysis gets more complicated.) This seems to surprise many people. Google for Blondel's theorem before trying to come up with an argument that the meter does not make this error. I believe you, and If I understood you, when speaking of mechanical meters the 1.5 element meter you describe has one voltage field across the 240 volt line and two current fields, one in series with each "hot" conductor. I think I see what you're referring to. Reducing it to absurdity, if you only load one side of the line, all the return current flows through the neutral, but the voltage field still "sees" the full 240 volts at the meter terminals even though the power you are using isn't the product of the current drawn time half of the 240 that voltage, it's the current times half of that voltage MINUS the voltage drop in the neutral. So, you get charged for the power equal to that current times the "full" voltage, when you are actually using power equal to that current times a slightly reduced voltage. Izzat it? Jeff N.B. This has nothing to do with the meter's being mechanical. You can build a 5-terminal (2 element) mechanical meter that does not have the error. I'm guessing that kind of meter must have TWO voltage fields? You can build a 4-terminal (1.5 element) electronic meter that does have the error. | And if so, can anyone | think of a plausible scenario, in any possible situation, real or | imaginary, that would let the device in the PDF picture (I can't tell | what it is -- just some kind of metal C-shaped thing I guess) do | anything that could even have a remotely possible chance of having even | a miniscule, undetectable, insignificant but still non-zero effect on | the meter? Maybe it's the AC equivalent of the "cow magnet" to be placed on the fuel ine of your car. :-) Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
#18
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How does an electric meter work?
kevin wrote:
Thanks for answering (partially) my question. This thread is interesting -- it seems to be filled with more BS and hype than the original link even was. I agree with almost everything said in this thread. I don't entirely understand your answer, though. I wasn't aware that there was a "neutral on the utility's side of the meter". And if there were, and I had a perfectly balanced load, then the neutral would have no current, right? Which means... no losses, and hence no cost? Obviously wrong... can you explain a little more? There is a neutral from the power transformer to the service panel (then beyond). A balanced load would result in zero service neutral current. An unbalance would result in neutral current, a small voltge drop and negligible power loss (small volt drop times current). If this were a big deal, all wire sizes including to circuits inside your house would be increased in size for lower voltage drop/lower losses. And moreover, there was a lot of BS in this thread about balancing the panel to begin with. To say that 240V devices are on both legs is irrelevant to the question of whether balancing a panel makes economic sense for the homeowner. Does a homeowner with a horribly imbalanced panel get charged more than the same homeowner if they just rearranged the breakers on the panel? -Kevin Far as I know meters accurately measure power used, balanced or not. The gizmo is a scam. (And if a steel (EMT) service entrance pipe is used the pipe shields the gizmo from the magnetic field.) Another scam, as others have said, is power factor correction - unless power factor is measured on residential meters, which I have never heard of. Even if PF is measured on residential some of these units are scams. bud-- |
#19
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How does an electric meter work?
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#20
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How does an electric meter work?
In article , (Jeff Wisnia) writes:
| Dan Lanciani wrote: | In article .com, (kevin) writes: | | | So can anyone answer the op's original question? Does a mechanical | | meter overestimate when the load is imbalanced? | | Yes, in the sense that the typical 4-terminal (1.5 element) meter most | often used in residential split-phase service charges the customer for | 150% of the losses in the neutral on the utility's side of the meter. | (That's the simple case of one service drop from transformer to customer. | For multiple connections the analysis gets more complicated.) This seems | to surprise many people. Google for Blondel's theorem before trying to | come up with an argument that the meter does not make this error. | | | I believe you, That's comforting. I've had some incredibly long threads (last in the alt.electrical.engineering group I think) trying to convince people that the meter could be wrong. | and If I understood you, when speaking of mechanical | meters the 1.5 element meter you describe has one voltage field across | the 240 volt line and two current fields, one in series with each "hot" | conductor. Yes, and I suspect most electronic meters are the same. After all, they plug into the same meter base as the mechanical meter they replace and there is usually no way for them to connect to ground/neutral reliably. | I think I see what you're referring to. | | Reducing it to absurdity, if you only load one side of the line, all the | return current flows through the neutral, but the voltage field still | "sees" the full 240 volts at the meter terminals even though the power | you are using isn't the product of the current drawn time half of the | 240 that voltage, it's the current times half of that voltage MINUS the | voltage drop in the neutral. Yes, though there will be some measured drop in the hot line as well so if hot-to-hot started out as 240V at the transformer it won't be 240V at the meter. It works out to your paying for 150% of the loss in the neutral: the sum of all the loss in the neutral itself plus half the loss in the loaded hot leg. Now on a multi-drop setup you could in theory make this work to your advantage. Take note of which hot leg appears higher with respect to the neutral (on account of your neighbors' unbalanced loads) and shift your own loads to this leg (but no more than will tend to pull the neutral to the other side of center). Now you are getting free power to the same extent of the metering error and at the expense of your neighbors. The power company always wins (or at worst breaks even if everything is perfectly balanced), though, which may be part of the reason they like undersized neutrals. | N.B. This has nothing to do with the meter's being mechanical. You can | build a 5-terminal (2 element) mechanical meter that does not have the | error. | | I'm guessing that kind of meter must have TWO voltage fields? Yes, the terminology seems to be (1 element) = (1 voltage field plus 1 current field). I don't really like this since it seems to me that "1.5 elements" could be ambiguous. Is the extra element a voltage or a current winding? Dan Lanciani ddl@danlan.*com |
#21
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How does an electric meter work?
Edwin Pawlowski ) said...
Power correction factor is different. It can be done inside, after the meter and is perfectly legal. I don't know if it is a viable option for residential, but for industrial use, there are savings to be had. It is not a viable issue for residential customers as they are charged for actual power used (kWh). Industrial users tend to have heavy motor loads that create a lagging power factor. With a power factor of 1, kVA is equal to kW, so the facilities needed to deliver 1000 kWh only has to be able to carry 1000 kVAh, and the losses due to heating that equipment is at its minimum. If the customer's power factor was 0.5, then the equiment need to deliver that same 1000 kWh needs to support 2000 kVAh! This means twice the current for the same power. Since heat losses are proportional to the SQUARE of the current, you lose FOUR times the power just heating the infrastructure. Industrial customers are charged for kVAh if they exceed a certain threshold, so it is in their interest to keep the power factor close to 1. They maintian large capacitor banks to do so. Residential customers do not generally run at a lagging power factor. In fact, it is likely they have a slightly LEADING power factor resulting from the combined capacitance of all the wiring in the home. I know this from when I used to work as a watchman in a plastics moulding plant. During the weekends when the plant was shut down, it was not unusual for the power factor to be about 0.9 on the leadinig side (there was a PF meter at the service entrance). As the plant was started up and various motorized equipment was started, the power factor would shift towards the lagging side and capacitor banks would be switched in. -- Calvin Henry-Cotnam "I really think Canada should get over to Iraq as quickly as possible" - Paul Martin - April 30, 2003 ------------------------------------------------------------------------- NOTE: if replying by email, remove "remove." and ".invalid" *** Posted via a free Usenet account from http://www.teranews.com *** |
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