Balancing the Breaker Box

wrote:


No, the meter measures *power*. As others have been trying to tell you, the torque (hence RPM) of the disk is proportional to the current times the voltage in the respective coils. No "calculating" at all and *certainly* there is no power factor calculated or measured.

...and reduces the neutral current, if that's important to anyone.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Big secret here, in a single phase AC circuit, Power= Volts X Amps X Power factor, multiply by the square root of 3 for a 3 phase circuit.

Yes, to my complete suprise there are many others here more ignorant about it than me. At least I can understand how the high leg current calculates to more KWH then the average current of the 2 legs, others have suggested things like magic bullets and free electricity :-)

Torque without friction or other limitations is infinite RPM so how do you get (hence RPM)?

Without power factor you are being charged for apparent power, not true power. Are you claiming that power meters measure apparent power, not true power?

I think Jim Sweet and others have it right, but I'm surprised how many others are willing to show their ignorance when it's is obvious they don't understand the subject. Perhaps a better explanation here: If you were using 10 KWH between L1 and neutral, and 5 KWH between L2 and neutral, you would be using a total of 15KWH. From what I heard another electrician saying, the power company would charge you based on the high leg, in other words you would be using 15KWH but the power company would charge you for 10KWH (the high leg) X 2 = 20KWH. If this were true, what balancing the breaker box would do is draw 7.5 KWH from each leg so that you would be using 15KWH and paying for 15KWH. Sorry for all you electrical engineer wannabees, but that is not a magic bullet, getting power you're not paying for, or anything like that. It would simply be using the power you're being charged for, there is nothing wrong with that.
Sorry, I'm not generally trying to be a smart a$$ but the golden rule is to treat others how you want to be treated. So for those that gave smart a$$ replies I reply back to you as you have replied to my post.
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

You have it backwards. Power factor is P/VA. Power factor is a "fudge factor" that describes the difference between apparent power and real power. PF is not a physical entity and is not measured directly.

Right, as you were repeating here.

Torque * RPM = HP The motor (meter disk) is doing work.

Again, you have it backwards. PF is the conversion factor not what's being measured. POWER is being measured. Directly. No conversion needed.

Honestly, the only one here (ignoring Proteus) that doesn't understand this, is you.

Wierd way of looking at it, but sure. That's the way the meter is designed.

The power company would be stealing from you. That's not allowed any more than you stealing from them. Laws are funny that way.

It's NOT true, so saying "if it were" is a meaningless exercise.

No wannabees here. Well, perhaps you wannabe.

Of course it is. It's a promise that cannot be fulfilled. Hucksters sell this sort of magic pill all the time.

Sorry you feel that way, but what you're posting (and continue to post) is crap. That's not the way things work, as you've been told here by *everyone*. Your electrician friends need to go back to school (and I am being kind).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If Power factor is P/VA then solved for P, P = Power factor X VA.

If you have a given torque on the meter disk, what limits the RPM? Is it generating a back EMF?

Well, I don't understand the stuff that's wrong.

There's lots of things a person can save money on or use more efficiently and it's not illegal even though it is pretty near stealing. One example is a 20oz soda often costs more than a 2 liter bottle of the same soda.

Nobody is selling anything, the guy telling this is not trying to get business balancing breaker boxes or anything like that. We work at as electrical techs in a factory repairing automated manufacturing machines, not wiring or rewiring houses.

Well, it was you that told me my calculation using power factor was wrong but then gave the same formula solved for power factor instead of power. My education was in electronics technology and we didn't go into the details of power meters and such, that is why I bring my question here. I don't have a problem being told that what I heard is not how a power meter works, I have a problem with those that try to tell me that a meter could not work that way or if it did then balancing the load would be like stealing electricity.
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

None of us are telling you that meters *could* not work that way, or that *if they did* work that way you would not be correct. What we are telling you is that meters *don't* work that way, so speculating what to do if they did is like speculating if the moon were made of cheese how best prepare it to eat. We know that it's not, so why worry about what to do if it is?
Given the way meters *do* work (they accurately measure power used), getting them to read less (not accurate, false reading) is stealing power. If the meters were ever behaving in a manner that caused you to get billed for power you did not actually use, regardless of the load balance, that would be fraud on the part of the power company. Again, this is irrelevant outside of this imaginary situation because this is not how they actually work.
I'm not sure what is so difficult about this concept. There is nothing to optimize, the rest of the discussion is a hypothetical (imaginary) situation.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I agree, if meters are accurately measuring the power used then there is nothing optimize as far as the power bill, it would only help to get the full capacity from your service. I just don't understand when I post something about using the power I'm paying for (based on being misinformed about the operation of a power meter) others want to turn it into me wanting to steal power and such.
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

No, there is a difference between the physical quantities measured and the conversion factor between them. You can't measure power factor, only derive it from power and VA.

Nothing limits RPM, other than the power measured. The whole idea is to measure the revolutions.

Yet you accuse engineers of not understanding electricity. <boggle>

You're talking nonsense again.

magical savings devices, like "Watt Savers".

I didn't say your calculation was wrong, just that you had the horse before the cart. You don't measure PF directly. It's the difference between watts and volt-amps.

It *would* be stealing. In this case it would be the power company stealing form the consumer.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
krw wrote:

Nonsense. Ever see a 'power factor meter'?? I have, on old switchgear systems. These only measured the phase-based power factor (harmonic content wasn't a problem in these old systems). But they simply developed a position based on the phase difference between the applied voltage and current (one input polarized a moving vane in a magnetic field created by the other input). Because the position of the needle actually showed the phase angle, the meter face was marked in a cosine pattern (i.e. the distance between 0.9 lagging position and the 0.8 lagging position was small, but the distance between 0.1 lagging and 0.2 lagging was larger).
The position didn't vary with the magnitude of the voltage or current, only the phase relationship (of course if current was below a certain threshold, the meter wasn't reliable)
daestrom
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Exactly. They don't deal with harmonics, thus are really phase angle meters.

So what? Without measuring harmonic content, they only measure phase angle not PF. ...unless you assume the world is a sine wave.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
krw wrote:

In the 30's and 40's, when these were often used, the world of electrical loads was a sine wave :-)
daestrom
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I know. I used to have such meters (a mechanically resonant Hz meter too). My father was a power engineer and *collected* stuff (several tons of such stuff in the attic when he passed).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

<snip>
What percent error is typically caused by ignoring harmonic content? Do the harmonics fool the utility meter or how does my power meter deal with harmonics? It just seems logical that if a utility power meter can measure true power, and a meter can measure apparent power (VA), then why should it be so difficult to measure power factor?
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

30%, 40%, maybe more of the VA is in harmonic content, particularly with electronics. Switching power supplies are often *very* bad.

They deal with it perfectly. We keep telling you that they measure *POWER*.

You can calculate PF from VA and power, sure, but that's not the same as measuring PF. Your logic is backwards.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motors, inductive loads, voltage leads current, capacitors, current leads voltage. Is a switching power supply more like a capacitive load or inductive load? I'm curious, I installed a 10HP variable frequency drive on my retrofitted CNC lathe. I ran the motor at idle and the drive showed 13A, but a meter only measured 5A on the line side. I have heard that the reason for this is that the drive handles the power factor problem, drawing closer to true power from the supply. If I understand correctly, a VFD is sort of like a 3 phase SMPS with the motor being the inductors in the circuit. Just wondering how this affects my household power factor versus other motors running from the line.
Also, before using solid state drives to get 3 phase from single phase, I used an old 10HP 3 phase motor to make my own rotary phase converter. I ran 240V into two of the legs and am able to run my shop from L1, L2, and the 3rd leg of the running motor. I use a single phase motor to spin the 3 phase motor up and then switch on the power. This thing drew a lot of amps until I installed some motor run capacitors to balance out the voltages. I don't have drives for all of my machines yet but I do for the ones I use the most, they seem to be a real nice way of running 3 phase equipment from single phase.
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Neither. It's a harmonic load. ;-) Uncorrected it has a very crappy current waveform.

A fully loaded motor should have a PF pretty close to unity. What any particular VFD does to it is anyone's guess. I suggest you buy a "Kill-A-Watt" or "PowerAngel", or some such. These things are about $25 and will report V, A, VA, W, PF, F, kWH, and H (did I leave anything out?). You can then play with various loads to get a feel for what they're about.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

<snip>
Thanks for the info. I found the Kill-A-Watt at Newegg for $20, plan to order one next order.
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 27 Nov 2009 18:44:25 -0800 (PST), Proteus IIV

I know that you're the stupidest hack on the Usenet, and that is pretty damned stupid, Roy.

Cheap shots for dumb asses.

No, you are Roy the Retard.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Several of the guys who answered you are probably EEs. They don't generally say much about it. Once in a long while, one might mention something he did in college or something about their certification. They don't have to brag about it. They'll generally know by reading each other's writing. They'll know in an instant I'm not one if the subject is at all technical. I didn't see much that looked like wise assed remarks. There wasn't anything close to the flames I've seen other places. People are just stating facts. The public service commissions or possibly the states' attorney generals should be all over this if it was real. I know scales at farmer's coops are tested for accuracy by the state. Gas pumps have stickers on them assuring their accuracy. States have bureaus of weights and measures to make sure things are according to hoyle. Why would they ignore the utility companies? What about all the lawyers running around? Think of the money a lawyer could make from a class action lawsuit if he won against a major utility. Here's a list of some of the things lawyers have sued for: http://overlawyered.com/tag/class-actions / One example there is a lawsuit against the makers of Froot Loops because they don't contain fruit.
Dean
Not an EE, and I don't play one on TV.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Maybe you're not an EE but you gave a better reasoned answer than many. Stating that a KWH meter does not operate based on the highest leg is a good answer. Comparing balancing a breaker box to trying to steal electricity or a magically creating electricity is absurd.
I'm not an EE either but I did electrical controls design and programming for many years and still haven't used close to 10% of what I learned to get an AAS. I have worked for and with both PE's and EE's and have learned a lot from many of them, but not on utility meters, it was always more in the industrial automation field.
RogerN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Go back and read over the replies again because nobody (aside from perhaps one of the trolls) has ever said that is the case. Trying to balance the breaker box is absolutely not stealing, nor is it magically creating electricity. The simple fact is that it will have zero measurable effect on the meter reading.
It was simply stated that since the meter already reads correctly, anything that did cause it to read slower (which does not include balancing) would be stealing power because given it already measures correctly, to get it to run slower without actually using less power would mean you are using some power that it is not measuring. Again, balancing your panel will *not* cause this to happen.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.