Unbalanced electrical load

[LD1]

An electric meter is a simple device. It only measures the amperage on the highest leg and charges accordingly.
To prove this theory check which leg has the highest amperage flow and measure the dial rotation. Then plug a 1500 watt electric heater into an outlet on the leg that has the lowest amperage flow and measure the dial rotation. You might find the dial rotation has changed. Then plug the heater into the leg that has the highest amperage and check the dial rotation. You will find it has increased.
The reason for this is the meter is baxed on 220-240 volt equipment which is supposed to draw equally from each leg..

I moved into an older house which had been remodeled several times. My electric bill was very high. An industrial electrician friend of mine explained this theory to me and loaned me an ampmeter to check the electrical panel over several days and several times during the day. I found one leg to be 8 amps higher than the other. I checked individual circuits and found by moving the breakers to equal the load on the incoming legs I saved $45 a billing cycle.
Check it out before you call BS on this.. Buying an ampmeter and balancing your home electric panel load will pay for the meter.. This is "probably" only necessary on older homes or maybe on newer homes that the electrician didn't care...
I have done the balance on my panel and know it works.. Dave

Ok orezok let me try again then.. Inside your mechanical type electric meter there is an induction motor that spins the wheels..with me so far ?? There are 2 wires on it that come from your house.. Lets say you are drawing 500 watts on one leg and nothing on the other.. Then you are being charged for 500 watts.. Lets keep the 500 watts going on the first leg and add another 500 watts to the second leg now you are paying for 1000 watts,, Still with me,,, Now lets unbalance the load lets add another 500 watts to leg number 1 now you are drawing 1500 watts total and are paying for 1500 watts..
Did I do better this time ??

We are still getting two opposing Ideas here

Based on daveomak's theory, IF you are drawing 1000watts on 1 leg, and only 500 on the other, you could add 500watts of consumption to the low side and the meter wouldnt read any more juece Not really free, just using what you are getting charged for becasue the meter assumes a balanced load.

Based on HR3's theory, 1000w on one leg, 500w on the other, and you are paying for 1500w. Add 500 to the lower leg, and now you are paying for 2000w.

Boy I wished someone know 100% for sure. But either way, I dont think it will make that much difference and there is NO way to be perfectally balanced ALL the time. All the big drawers are 240 so they are already balanced. And I dont have any major 120 items. They are all computer, lights, things like that. And daily consumption and usage changes A LOT. So it is hard to pin down.

 

[orezok]

Ok orezok let me try again then.. Inside your mechanical type electric meter there is an induction motor that spins the wheels..with me so far ?? There are 2 wires on it that come from your house.. Lets say you are drawing 500 watts on one leg and nothing on the other.. Then you are being charged for 500 watts.. Lets keep the 500 watts going on the first leg and add another 500 watts to the second leg now you are paying for 1000 watts,, Still with me,,, Now lets unbalance the load lets add another 500 watts to leg number 1 now you are drawing 1500 watts total and are paying for 1500 watts..
Did I do better this time ??

Much better thank you, but from what I understand, one leg provides the voltage reading and the other the amperage for the "induction"motor. Together they measure wattage. But what if the leg measuring amperage is out of balance? The voltage leg will always be constant, the amperage leg can vary.

 

[EMB5530]

load balancing is somewhat important
but only if you are using plenty of power
energy use= heat
heat=resistance
resistance=inefficency
therfore you pay more if you are using a lot of power on one leg and not on the other because you are losing power to heat.
but most of the time there is not enough draw on a leg to make a diff unless you are using a lot of high amp 120 volt devices.

 

[BobRip]

Much better thank you, but from what I understand, one leg provides the voltage reading and the other the amperage for the "induction"motor. Together they measure wattage. But what if the leg measuring amperage is out of balance? The voltage leg will always be constant, the amperage leg can vary.

They measure the current on both legs. This is basic electrical engineering.

Follow this link, it is for a 3 phase meter, but the concept is the same.File:Block Diagram.JPG - Wikipedia, the free encyclopedia

If you only measured on one leg, rather than balancing the load, you should move as many loads as possible to the unmeasured leg. Why do they not propose this? The power companies know this could happen so they measure both current legs.

 

[cttractor]

FOR THE RECORD: the devices on homes and businesses are watt-hour meters. That means they measure the actual watts of power consumed whether the loads are balanced or not. They DO NOT have induction motors -- they have synchronous motors and turn the wheel we've all seen. The shaft that turns that wheel also drives a small gear network that drives the shafts of each of the small gauge needles that display total killowatt hours (kWh) consumed and that the meter reader reads each month..

In many utility districts across the country (and the world, now), the older meters we all knew have been replaced with digital meters -- in time, they will all be replaced. These, too, measure the actual watt-hours consumed regardless of balanced or non-balanced loads. The future, whether we like it or not, will be for utilities to move to time-of-day rates. That means that when electric loads are higher during a hot summer day due to higher A/C loads and higher cost generation assets are being brought on line, that we will be paying more per kWh. Power will be cheaper in the evenings and weekends when loads are less because many businesses are not producing and cooling offices.

The discussions I'm hearing are that customers that don't want to switch to a time-of-day rate will be allowed to stay on a flat-rate as we are now, but that the price per kWh will be higher for flat rates so as to capture a more accurate average cost compared to time-of-day rates. In addition, those meters will be sending our minute-to-minute usage to the utility company for analysis. This analysis is so the utility can perform capacity planning computer simulations so as to determine how much more generation they need to build to accommodate future load increases. it also allows them to see who's creating the largest demand from existing feeders and substations.

I know many won't like reading this post, but it is the truth and where the industry is going.

 

[DaveOmak]

Ok, let me try this again....
For those of you who think the 2 legs can be unbalanced and the watt/hour total is correct, you must assume there are 2 inductance motors in the meter reading each leg and then there is a third device that averages the reading from the 2 legs and charges you accordingly...

Wow, that would be one expensive meter...

Or you think if one leg is running 10 amps--1200 watts and the other leg is using 0 amps--0 watts, then the induction motor on the 10 amp leg must somehow record only 5 amps--600 watts of consumption..

Or each leg is balanced 10 amps--1200 watts...
Then the meter somehow has to add these 2 readings together and charge 2400 kwh ...

I will again describe the meter function.. It reads the highest leg and assumes both legs are the same... the meter is not smart enought to balance and calculate different loads on each leg...

If you want to possibly save yourself some money, check the amperage on each supply leg.. if there is a continual difference between the 2, there is an unbalanced load and you are paying too much on your bill.

Say the imbalance is 1 amp. (basically a 100 watt light bulb for demonstration)
1 amp is 120 watts/hour (amps x volts = watts)
120 watts x 24 hours/day = 2880 watts/day
2800 x 30 days/billing cycle = 86400 watts/billing cycle = 86.4 kilowatt hours / billing cycle
86.4 kwh @ $.10 / kwh = $8.64 biling cycle you are giving to the power company....

I know there are folks who will not believe this..
They think the power company would not allow this type of situation to continue.. (overcharging for power used):mur:

 

[LD1]

I will again describe the meter function.. It reads the highest leg and assumes both legs are the same... the meter is not smart enought to balance and calculate different loads on each leg...

If it is not smart enough to calculate and balance different loads, then how is it smart enough to know at every exact moment which one is using more???

I dont believe this is the case, but I could be wrong.

I do agree with those who say that you pay for what you ACTUALLY use regardless of balance.

Becasue the balance is never perfect. You can arrange your breakers however you want, but what if you turn off a light in one room and go to another? SAME exact wattege bulb. If you were perfect balance before, taking 1 amp (as per your example) from leg and adding it to the other will now magically make your electric bill increase. I really can see this being the way things work.

And what about the digital meters. You keep talking about the old "wheel" meters. Do you believe the new meters are the same way? Because I know if they are smart enough to send all my imfo to the power company, they are sure smart enough to take an ACTUAL reading as opposed to only the higher leg.

 

[tsteahr]

We can do a simple test. Vary the loads on each leg and measure the time it takes the wheel in the meter to make one revolution.

Make sure all of the major loads in the house are switched off. Then get a couple good 110v loads going on one leg, say a hair dryer and a portable electric heater. Together draw 20 amps or more. Go measure the time, then plug a power tool (like a 15 amp skill saw) into a outlet on the other leg. Use a extension cord and you can stand at the meter and watch the meter change speed as you turn the tool on and off.

On my meter, the more I draw, the faster the wheel spins, regardless of which leg or how the loads are balanced. I have one of those newer electronic meters.

 

[Stonehaller]

There are multiple types of electric meters. They do not measure current in the neutral leg. Most measure current in both legs and will correctly measure unbalanced loads. But there are probably still some old ones around that only measure current in one leg and therefore will not measure an unbalanced load correctly.

 

[LD1]

We can do a simple test. Vary the loads on each leg and measure the time it takes the wheel in the meter to make one revolution.

Make sure all of the major loads in the house are switched off. Then get a couple good 110v loads going on one leg, say a hair dryer and a portable electric heater. Together draw 20 amps or more. Go measure the time, then plug a power tool (like a 15 amp skill saw) into a outlet on the other leg. Use a extension cord and you can stand at the meter and watch the meter change speed as you turn the tool on and off.

On my meter, the more I draw, the faster the wheel spins, regardless of which leg or how the loads are balanced. I have one of those newer electronic meters.

That would be an excellent test. IF you are drawing 20A on one leg, and fire up a 15A load on the other, according to daveomak, you would see no change in how fast the meter spins, as it would still only see the "high" leg @ 20A.

But I believe there would be a change. But I cannot test this theory cause I have a digital meter:confused2: