Energy Saving to 25%

It's true that older meters measure active power only. The distribution companies have been on a push to install new digital meters that have many upgrades. One being the abitlity to charge the customer for its reactive power. These caps will correct the customer's power factor essentially increasing the efficiency of the power entering the building. As far as a 25% savings, it all depends on your current power factor. Large industrial customers will buy capacitors to correct this. The big push in the residential market is to replace the incadescent lightbulbs with CFLs with electronic ballasts that increase PF. These caps add a capacitive load in your house to correct the PF. If you're going to invest in these, you should ask the utility if you're type of meter can measure reactive power. It's in the best interest of the distribution companies to put these every home. The most efficient power runs at unity(PF = 1). As an example, say your home has a combined PF of .7 The utility has to supply you with 30% more power than you would need if you would need if your

PF = 1.

thanks your comment, but in my house there are active power meter only. we pay active power fee only.

Hello JReaf: I believe we are thinking along the same lines. You correctly stated the only energy that is actually lost is that due to the increased current therefore increased resistive losses.

Pure inductance lags by 90°. Pure capacitance leads by 90°. Neither the energy stored in the magnetic field of the inductance or the charge on the capacitors plates is lost to the utilities, it's simply shuttle's back and forth to the grid.

I thought the original poster might be interested in knowing that even if his power factor was being monitored the savings would probably only be 11% not 25%.

http://me.oregonstate.edu/iac/downloads/Power%20Factor%20401.pdf

BTW I intend to refer a friend to this forum. He'd seen a demonstration of the device mentioned (which we know is just some capacitors) and was not thoroughly convinced by my explanation and my assurances that it would not actually save him money on his utility bills.

PS. Score 1 for a good answer. If your post convinces my friend I'll try and find some way to make it two.

Good answer, you've saved me saying the same, so I've voted it.

All I can add is, in a commercial or industrial situation PF correction can become essential on large lighting circuits from an inrush point of view. Lazy or uneducated electricians chop put failed PF capacitors rather than replace them, then they wonder why the circuit breaker pops on start up. When faced with this fault, after meggering the circuit, I try a few caps until the inrush reduces, then replace them properly. What goes unrealised is that when the fluoro is starting and the filaments are in circuit PF is low and impedance is low. With a large amount of fluoros on a circuit the inrush can soon exceed the breaker (and therefore cable) rating for a short time. The correctly sized capacitor connected directly across the light fitting puts a capacitive (XC) path in parallel with the combined R and XL creating a "Rejector Circuit" increasing the circuit impedance and reducing inrush. The reactive power required by the ballasts (traditional choke types) is provided by the cap.

Summing up, for power factor correction to be of direct benefit to the consumer it needs to be installed at or close to the device requiring correction.

There have been scam devices people make to try and fool the meter by phase shift, because at 0.5 PF mechanical meters don't register reliably. In this country if someone has such a device installed they get prosecuted.

Please expand this sentence so that I am sure that I understood you fully and correctly:-

There have been scam devices people make to try and fool the meter by phase shift, because at 0.5 PF mechanical meters don't register reliably. In this country if someone has such a device installed they get prosecuted.

The arrangement of the current coil and the voltage coil works quite well at the usually expected power factor of .8 to unity. When the power factor gets to .5 the disc can stop turning and can even run backwards. For instance 415 vac welders of some designs cause the meter for one phase to run backwards (where 3 seperate meters are used instead of polyphase). The welders are actually 415v single phase connected to 2 phases of a 3 phase system the resulting phase shift causes one meter to reverse. The supply authorities claim a leading PF of about .5 will also reverse the meter for exactly the same reason, (then they inform any Lecky who may wish to try it what the consequences will be). The coils and pole faces are fixed in position so can't adapt to radical phase shifts.

"the TOTAL LOSSES are already only 10% of 750W, or 75W. Of the 75W, maybe 35% is I²R loss, so we are down to 26W of I²R losses. If by improving the power factor from .8 to .95, you reduce the I²R losses by 25% (another very generous assumption), you are now down to a savings of just 6.5W. "

You are right! These are the I²R losses in the motor. But these losses will not go away when adding power factor correction capacitor before the motor. The capacitor has no effect whatsoever on the motor losses. It only reduces the losses of the supply system that are much less than the motors. So it will take more like 100 years to pay back for this capacitor.

Power factor compensation techniques are only useful for large industrial loads. They also bring risks of damage from resonance when too much compensation is added. These capacitor tend to fail after a few years if sized improperly as they are exposed to destructive line voltage transients and harmonics.

We see many weirs installations in this field and some of them cause more problem than they solve. And this is for informed industrial users.

Good answer.

I rate your answer as good and give you a GA point.

You neglected to mention though that the reactive power flows also circulate and add to the current flowing through the cables and that it is at least theoretically possible that a weak point in the cable (outside the home) could be damaged......or a transformer overheats in a substation.....

I personally feel that it may be a good move eventually to try and correct ones own PF, especially if a more modern and correct method of power metering comes into use.

Maybe we should have a separate blog on designing such a system for home/small business usage?

Hello Andy you said :

Maybe we should have a separate blog on designing such a system for home/small business usage?

I think you're right it could be worth exploring this issue. So let's start a blog, I figured it was your idea , so it's your turn this time I'll do it next time.

Both you and the guest that posted below me have a perfectly valid point. A straight up and down power factor is best. As the guest mentioned utility companies correct their local power factors with capacitors, there are multiple reasons to do this on the large-scale.

What bothers me about the device the original poster was referring to is the exaggerated claims. Everyone knows a good lie contains as much truth as you can twist. This is the premise that most free energy claims operate on.

In the specific case one of the demonstrations is to show a drop on an amp meter when a capacitor is put across the load and inferring this is energy saved. I personally have done the same demonstration when explaining inductive and capacitive reactance to a vocational class I was teaching. The advertising for this device states that they are recovering waisted energy, a lie.

The energy that is stored in the capacitor is utilized in the motor. However the energy that is stored in a magnetic field of the motor is utilized by other devices in your house or returned to the grid. The only real net energy savings is less resistive loss. The wiring runs a little cooler less heat less loss, however for correctly sized wiring it would be an extremely minimal savings.

The advertising for this product shows heat loss of the appliances as wasted energy and infers their device stops this. Again a lie. Having a capacitor across the circuit feeding the refrigerator changes nothing internal to the refrigerator.

Additionally having too much capacitance would cause a leading power factor putting as much extra load on the circuit as a lagging power factor. Since the lagging power factor of your house or small business is constantly changing with the number of motors running so how does the device compensate for this? If it does compensate then it must be using energy both when utilized and when not.

On the large-scale, a plant, a section of the grid is pretty easy to figure a constant average power factor . On the small scale such as your house the power factor changes dramatically when your air conditioning runs.

Possibly a better way of correcting power factor in residences would be to install a capacitor inside the device that is the culprit. I.e. your air conditioning condenser parallel a capacitor across the contactor that energizes with the condenser and correct your power factor, for about $10 instead of 299.95.

Deceptive advertising, I can easily construct a device that will allow you to plug a 220 V motor into 120 V outlet and you will see 220 V at the motor. You could advertise this as cutting your power in half when in reality nothing is changed.

By the way I'm not talking about a transformer merely putting a capacitor of the correct value in series with the motor will do it, I know I've actually done it with a fractional horsepower motor when I did not have the correct voltage available.

So correcting power factor good. Deceptive advertising bad. That is of course unless I can market my energy saver that saves you 50% off your voltage, a plus to my device is it also corrects your power factor. So my actual savings would be 75%.

I Am including a link to take you to the power saver 1200 site.

http://www.powersavemi.com/product.html

PS. Send me a private message if you think we can sell my device, I will give you a piece of the pie.

You know Andy, in Canada back in the '50s, service men went to all the houses and businesses in Canda and installed capacitors in the appliances to adjust the power factor. I believe that the motors in use before that had a lousy PF, and this unusual and expensive move actually provided the 25% savings from adjusting PF.

I don't know much about this...it was before my time, and was mentioned in my electrical training courses. I remember it specifically because the question was "could increasing capacitance in the house reduce your electric bill", and the answer then was, "No, because it has already been done".

All motors in my experience have a large capacitor attached to them now and the antique ones out in the shop do not. I always assumed that was the reason why. Do you suppose these claims of great savings are based on pre-50's ways of distributing power?

As you can see, my concept of PF is fairly solid, but the idea of saving appreciable amounts of money by adjusting it needs some work. (Actually, my experiences are a bit different....the huge electrical runs in aircraft hangers result in a detrimental PF the 'other way", because of the excess capacitance resulting from the supply lines reacting with their conduit. I support a separate blog dealing with these issues since corrrectly adjusting PF might result in fewer tonnes of coal being burnt in the power plant.

Interesting I did not realize that the capacitance of the supply line could cause such a dramatic impact.

As far as motors the old ones were a lot bigger and heavier and probably had a little poorer power factor. At least the single phase motors. Many different starting techniques have been used over the years, some even predate me. Currently the most common starting devices for midsize single phase motors are capacitor start or permanent split face capacitance. The PFC motor would have a slightly better power factor however the net result is still a lagging power factor.

Three phase motors power factor should have largely remained unchanged over the years.
I would be interested in knowing if Canada at the time was penalizing residential customers for having a poor power factor.

Hola (no, I am not actually Spanish) Anyhow, while the above poster's comment about power through capacitors not being lost is true, that is simply shuttled back and forth across the grid, it should also be noted that by shuttling power back and forth you lose energy in the utility mains. Is it worth trying to improve your power factor? Well, the lad above did the math and it appears not (I'm not the same guest that posted earlier, by the way). Also, most power utility companies have very large capacitive networks, so they already do quite a bit in the way of correcting pf.

Most of these particularly related to lighting reduce the voltage and consequently the lumens as well.But it is not perceptible.thus they achieve the savings.many controllers for motors also sense load currents and reduce the voltage.The other thing is a fair one where we have lower wattage lamps giving higher outputs in terms of lumens.

I was thinking about that while I was doing my posts, and almost deleted that line. I left it in for two reasons.

The first is that I am an agitator, I love stirring things up, but you never know what will be the final outcome of the discussion. There's always something to be learned.

The second reason is the validity of your point. It could ultimately save money by cutting transformer size and wire size that the utilities have to supply for a given area. Along with the small savings the consumer would see in reduced resistive losses. Hopefully the utilitys savings would be reflected on our electric bill's.

Many who frequent this website will be able to safely install capacitors in devices that have poor power factors. This would be a simple and economical solution as you suggested, and can be automated using the equipment's internal controls.

For the average consumer however this would be a dangerous proposition. The returned would never justify the expense of having a professional installation.

However while thinking about the subject another solution came to mind. Air-conditioners, refrigerators, washing machines anything with a relatively large motor are the major contributors to poor power factors in residential and small business. The cost to modify this equipment at the manufacturing level would be extremely small, probably less than $10 for most applications.

The power factor correction for any motor varies with the load, so it would be impossible to cheaply correct the power factor to unity under all conditions. However it will be very inexpensive as mentioned to get close.

If all new small equipment was to be modified in this manner there could be potentially a dramatic savings in infrastructure costs, as well as transmissions losses with very little investment. That might be worth discussing or proposing to the green guys.

PS. I can think of the few other people ,without mentioning any names that like to stir things up. Great fun isn't it!

Liked your post (all of them really) especially the PS (Pool Shit?) on the last one.

Yes I have to agree, the correction should be made inside the device, that is the best way to go for all.....

Do you have a diagram for a simple PF phase meter or add on for a normal meter? that is really the first requirement!!

With three or four different value capacitors, you can wire them in series or parallel or a combination and probably get 15 different values, (without doing the math).

BTW. The HVAC supply houses are currently sell a capacitor, that is actually a 4 in 1 with a wiring diagram to do just that. I guess this is so you don't have to do what I was talking about in the middle of the night to come up with the right capacitor.

As far as savings personally I think if you were lucky and got the capacitor at a good price, put it in a brand-new air-conditioner, it might pay for itself in 15 or 20 years but I've been wrong before.

On the large scale if the manufactures corrected power factor in their equipment there might be a substantial savings in reduce infrastructure, and transmission losses. We probably wouldn't see it, but it might be good for the environment.

I somehow feel that a "private venture" is simply not worth the trouble, unless electricity meters are replaced with a more accurate version that takes into account the wattless current......but I will not forget your idea, many thanks for sharing that with us.

Hi, if you want to make your own P.F. meter, put a rated ac voltmeter across the line and a rated ac ampmeter in series with the load and read volts times amps equal volt/amps or VA or KVA

Is that not the "cheap version" eg. the "Wattless Amps" with No PF indication.

I want a PF meter.....