box hooked to panel to save money

[electricalist]

Has anyone installed one and what's inside them.
The ones I did were a 6x6x6 box with a 240v 20 amp whip.
Hook it to a 2 pole 20 amp breaker.
Supposed to save customer money.
Unless it a box full of electricity I don't see how.

 

[growler]

It works on faith, you must be a believer for it to work.

 

[Buck Parrish]

It's like Snake oil.

 

[infinity]

Probably for power factor correction. General consensus here a while back is that they are snake oil and useless.

 

[gar]

141129-1319 EST

electricalist:

It is a fraud. What was the total cost to the customer, box plus installation? I heard from one builder $1600.

Inside is a single high quality capacitor, probably polypropylene, about 70 mfd. And some MOVs.

Real value of the box is about $100. Usually sold from $200 to $400.

Essential no saving in electric bill.

.

 

[Ponchik]

IMO and from the little knowledge that I have, these units are similar to and have the same concept to power factor capacitors.

PF capacitors do work on industrial establishments that have multiple motors but the tiny device probably will not save any significant dollars to offset the cost of the installation.

 

[don_resqcapt19]

...PF capacitors do work on industrial establishments that have multiple motors but the tiny device probably will not save any significant dollars to offset the cost of the installation.

But even in industrial applications PF correction does not save much money unless the utility charges a penalty for low power factor.

 

[meternerd]

IMO and from the little knowledge that I have, these units are similar to and have the same concept to power factor capacitors.

PF capacitors do work on industrial establishments that have multiple motors but the tiny device probably will not save any significant dollars to offset the cost of the installation.

Electric meters charge by Watt hours, not VA hours. We test them at 50% PF and they have to still run at the same speed as at 100%. Tolerance is +/- 0.2%. Additional charges for PF are separate, and apply only to commercial meters.

Capacitors may reduce current slightly (assuming an inductive load), but at no cost saving to the residential user. If it's also a surge suppressor, that may add some protection, but not a cost savings.

Waste of money. In my HUMBLE opinion (to which everyone is entitled), of course.

 

[electricalist]

We were paid by a builder to install them in his custom houses,that trend passed.
Now many years later a small city we do work for had us install them on all the well pumps,fire dept and police dept panels.
I asked, why are you sure they work. He said they have the analysis of how and where they will save the money.
I said unless you already have them installed then there's no proof of the savings as well as no proof they won't save money

 

[gar]

141129-1704 EST

With a well controlled experiment you can not show any benifit by use of capacitor power factor correction for a customer that does not get charged a PF penalty, and the PFC is placed at or within a few feet of the meter.

Following is some data I put in my notes on "Electrical Energy Measurement, Conservation, and Methods to Reduce Your Electric Bill":

1. The motor is an old 1/3 HP 115 V induction motor. Unloaded very poor PF.
2. Test with no external mechanical load.
3. Motor was run long enough to reach thermal stability.
4. Input voltage was held constant at 117.0 V
5. A Kill-A-Watt was the current, VA, and power measuring instrument. This is quite good with varying power factor. A TED ststem is not.
6. Results

Capacitance  Input   Input   Input    Input 
     mfd     Amps    Watts   VA       PF

       0      4.71     140    552      0.25
      30      3.44     141    400      0.34
      60      2.30     141    270      0.52
      90      1.45     142    168      0.83
     102.5    1.33     142    158      0.90
     120      1.58     143    185      0.78

If the municipal organizations put PFC at the load, switched with the load, and have long wire runs, then some small saving in energy will occur. But a loaded motor will not have a real bad PF. So there is not a lot of current change. If the motors are single phase capacitor run, then their power factor alone is quite good.

.

 

[meternerd]

141129-1704 EST

With a well controlled experiment you can not show any benifit by use of capacitor power factor correction for a customer that does not get charged a PF penalty, and the PFC is placed at or within a few feet of the meter.

Following is some data I put in my notes on "Electrical Energy Measurement, Conservation, and Methods to Reduce Your Electric Bill":

1. The motor is an old 1/3 HP 115 V induction motor. Unloaded very poor PF.
2. Test with no external mechanical load.
3. Motor was run long enough to reach thermal stability.
4. Input voltage was held constant at 117.0 V
5. A Kill-A-Watt was the current, VA, and power measuring instrument. This is quite good with varying power factor. A TED ststem is not.
6. Results

Capacitance  Input   Input   Input    Input 
     mfd     Amps    Watts   VA       PF

       0      [B]4.71[/B]     [B]140[/B]    552      [B]0.25[/B]
      30      3.44     141    400      0.34
      60      2.30     141    270      0.52
      90      1.45     142    168      0.83
     102.5    [B]1.33[/B]     [B]142[/B]    158      [B]0.90[/B]
     120      1.58     143    185      0.78

If the municipal organizations put PFC at the load, switched with the load, and have long wire runs, then some small saving in energy will occur. But a loaded motor will not have a real bad PF. So there is not a lot of current change. If the motors are single phase capacitor run, then their power factor alone is quite good.

.

Not to be nit-picky (is that a word)?....but in your test at .25 PF. should be 117V x 4.71A = 551 VA x .25PF = 137.77 Watts

.90 PF should be 117v x 1.33A = 155 VA x .90PF = 140.05 Watts

So your voltage must have not been exactly 117 at .25 or your PF was not quite what it said it was. Ohm's law states that V x A x PF = Watts, so the test should have shown no change in watts for a constant voltage. Our testers are pretty sophisticated and the PF test is variable from 1.00 to 0.00 leading or lagging. The meter must remain within tolerances at any PF to be considered calibrated. The solid state ones are dead on. Mechanicals will drift some, but not much. I don't see how PFC with long runs could possibly save energy (watts) at the meter. VA yes, VAR yes, but Watts? Hmmmm.....

 

[gar]

141129-2347 EST

meternerd:

All the values in the table were read from the Kill-A-Watt. Further the 117 V is manually controlled by a Variac that can not be adjusted to 0.1 V. Approximate step values are about 1 V at 120 V, sometimes slightly better. Note, the Kill-A-Watt is not a precision instrument but is rather good and something almost anyone can afford to purchase at less than $30.

The measurements were not meant to be precision, but sufficiently good to demonstrate that there is virtually no power change.

Sufficently good meaning that the data is adequate to prove that there is no economic value in these boxes.

If you would run a similar test and provide data with greater accuracy that would be useful.

.

 

[electricalist]

Its my guess that in the new homes we put them in it was a selling point to help the customer believe they got a better deal.
In the city install probably a way to get more funding cause"were doing every thing we can to be efficient."

A product that uses electricity so you use less electricity.

 

[kwired]

Its my guess that in the new homes we put them in it was a selling point to help the customer believe they got a better deal.
In the city install probably a way to get more funding cause"were doing every thing we can to be efficient."

A product that uses electricity so you use less electricity.

Exactly right in both instances. How the sellers market these is easy to convince someone that doesn't know electrical theory very well that they will have some savings benefits.

They often use a simple set up with a small unloaded single phase motor, an amp meter, and of course their device they want to sell.

When someone that don't understand enough theory sees the amp meter has a lower reading with their "black box" in the circuit, it seems like a good deal. Little do they know that the motor is running at a low power factor, that the typical single phase service is not charged power factor penalties, and that if they were to put a watt meter (which is what is more important for billing purposes) on the circuit instead of a amp meter that there would be very little difference in readings. What they also don't know is that if you have no inductive load running at any given time that box is adding some current instead of cancelling the inductive reactance from an inductive load.

They have probably carefully sized these units (maybe in more then one size) to apply them to some average sized installations to show best overall power factor correction results to a few common situations - but again if the POCO doesn't charge penalties for low power factor - the savings just isn't nearly as high as they may claim it can be.

Your city officials that have agreed to utilize these devices - are likely not electrical professionals, if so they are not fully aware of what these are all about or how they work, or they would not agree they are needed. They are just average people that bought the sales pitch.

 

[gar]

141139-1222 EST

meternerd:

On review the data in my table is actually quite consistent. Not that I necessarily expected that.

Power factor is not a directly measured value, rather it is calculated from power and VA. In line one of my table 140/552 = 0.2536, and rounding to 2 places produces 0.25 . In line 5 we have 142/158 = 0.8987, and this rounds to 0.90 .

Line 2 comes out 0.35 instead of 0.34 .
Line 3 rounds to 0.52, no difference.
Line 4 divides to 0.85 instead of 0.83 .
Line 6 divides to 0.77 instead of 0.78 .

I don't know the source of these errors. Could be normal line voltage fluctuation between the time of one measurement, and another.

.

 

[electricalist]

You can tell a customer, I can put motion sensors on lights that are on too long and upgrade lighting to be more efficient all for 1000.00 and they'll so no but you can say or I got this Greg box that warranty is void if you open it. It hooks to a breaker and goes no where. Plus it comes with a fact sheet so complicated you won't know where to file it , I can install it in 30 min.for 2500.00 They all say........
Femme the grey box every time.:thumbsup:

 

[kwired]

You can tell a customer, I can put motion sensors on lights that are on too long and upgrade lighting to be more efficient all for 1000.00 and they'll so no but you can say or I got this Greg box that warranty is void if you open it. It hooks to a breaker and goes no where. Plus it comes with a fact sheet so complicated you won't know where to file it , I can install it in 30 min.for 2500.00 They all say........
Femme the grey box every time.:thumbsup:

When you give them two offers like that and they choose the one that doesn't make much sense....I guess you probably profit more on their ignorance in those instances, but you also tried to tell them something that is reasonable. Electricians don't seem to do it as often, but a lot of service companies as well as outright retail sellers have in recent years have made big profits from these "extended warranties", which I myself never buy on anything. But maybe I should start selling them, as I've seen many that don't even think about it and just agree to purchasing these warranties when asked.

 

[meternerd]

Exactly right in both instances. How the sellers market these is easy to convince someone that doesn't know electrical theory very well that they will have some savings benefits.

They often use a simple set up with a small unloaded single phase motor, an amp meter, and of course their device they want to sell.

When someone that don't understand enough theory sees the amp meter has a lower reading with their "black box" in the circuit, it seems like a good deal. Little do they know that the motor is running at a low power factor, that the typical single phase service is not charged power factor penalties, and that if they were to put a watt meter (which is what is more important for billing purposes) on the circuit instead of a amp meter that there would be very little difference in readings. What they also don't know is that if you have no inductive load running at any given time that box is adding some current instead of cancelling the inductive reactance from an inductive load.

They have probably carefully sized these units (maybe in more then one size) to apply them to some average sized installations to show best overall power factor correction results to a few common situations - but again if the POCO doesn't charge penalties for low power factor - the savings just isn't nearly as high as they may claim it can be.

Your city officials that have agreed to utilize these devices - are likely not electrical professionals, if so they are not fully aware of what these are all about or how they work, or they would not agree they are needed. They are just average people that bought the sales pitch.

Kwired....I'm certainly not expecting that test setup to be as accurate as an umpteen thousand dollar meter test bench. No offense meant. I just was trying to point out that there will be NO cost savings by correcting power factor if all that is charged for is KWh. To believe otherwise means the advertising is working, saying you MAY save. You won't. Ohm's Law. Sorry I can't do a test on the high dollar equipment. Being retired I no longer have access. But take my word for it. KWh meter test results done at 100% and 50% PF consistently show no change in accuracy (within 0.1% on solid state meters). I suppose it's possible there may be some tiny saving due to lower I2R losses if total current was reduced, but I doubt it.

 

[kwired]

Kwired....I'm certainly not expecting that test setup to be as accurate as an umpteen thousand dollar meter test bench. No offense meant. I just was trying to point out that there will be NO cost savings by correcting power factor if all that is charged for is KWh. To believe otherwise means the advertising is working, saying you MAY save. You won't. Ohm's Law. Sorry I can't do a test on the high dollar equipment. Being retired I no longer have access. But take my word for it. KWh meter test results done at 100% and 50% PF consistently show no change in accuracy (within 0.1% on solid state meters). I suppose it's possible there may be some tiny saving due to lower I2R losses if total current was reduced, but I doubt it.

There issavings, but there is not enough to matter, and depending on load conditions there could be times the capacitor is actually adding more true watts then it is reducing. Cut the total amps down by reducing the "apparent" power does reduce how much line loss occurs. But in a typical dwelling or light commercial building those losses are typically such a small amount that they have almost no impact on the energy bill. The thing may correct PF enough to make some difference when the AC is running, but the constant draw of the capacitor does have some resistance value to it and possibly wastes enough energy when the AC is not running that it all kind of washes out in the end. Many other motors just don't run long enough period of time to have much benefit at all from correcting PF.

 

[gar]

141201-1123 EST

Correcting power factor at the main panel does nothing to reduce line losses that the customer pays for. Normally there are only a few feet of wire between the panel and the meter.

And the main panel is where these whole house PF boxes are installed.

.