Home PF Correctin

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ohmhead

Senior Member
Location
ORLANDO FLA
I know what you are getting at. But it's more correctly inductive reactance and capacitice reactance you want to match and (nearly) cancel. The reactance depends on supply frequency rather than the natural LC resonance frequency. In fact, natural resonance is best avoided in most cases.
I measured this current waveform a couple of weeks ago:
Unwantedresonance.jpg

The fundamental is 50 Hz (UK) but clearly there is a whole bundle of other frequencies mixed in.
Not good.

Well yes we agree we kinda know why or how but just have trouble putting it into words . We didnt really mean resonant circuit just a better inductive to capacitive balanced one .
One thing i see is if you leave PF alone or increase your now bad PF your watt meter will actually read less wattage so your cheating the local power company maybe this why one box does fit all ? Comments lets look at not saving power but what about a increase in a BAD POWER FACTOR ?
Maybe thats what they are doing ? Take care naa cant be maybe Gar needs to put a O scope on that p1200 box lets look at the wave ?
 
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gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
090511-1906 EST

ohmhead:

One thing i see is if you leave PF alone or increase your now bad PF your watt meter will actually read less wattage so your cheating the local power company maybe this why one box does fit all ?

You statement is incorrect. A residential watt-hour meter measures the cumulative energy you use from one reading to the next. Energy is work done. Work is raising a weight, using friction to generate heat, running a fan to move air, heating a resistor, etc. This work is what the watt-hour meter measures.

If you have a motor with a bad power factor doing some work. For example: no external load on the motor, but thru bearing friction and windage work is being done. This motor will have a low power factor because it is not doing much work in comparison with its capability. Thus, the inductive excitation current is large compared to the resistive component. The resistive component is a result of the work being done.

Add power factor correction, a capacitor, this will reduce the reactive current as seen looking at the motor and capacitor combination. It has no effect on the resistive component. The resistive component does not change if the voltage, frequency, and load do not change.

An ideal watt-hour meter only uses the resistive component in combination with the voltage to determine energy usage. Improving the power factor does not cheat the power company,

Read thru this whole thread again and see if this has not been said many times.

The post where I provided experimental data with a lamp and capacitor showed that a large change in power factor had no effect on the power reading. The slight increase in power with the capacitor connected was from resistive losses in the capacitor.

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ohmhead

Senior Member
Location
ORLANDO FLA
090511-1906 EST

ohmhead:



You statement is incorrect. A residential watt-hour meter measures the cumulative energy you use from one reading to the next. Energy is work done. Work is raising a weight, using friction to generate heat, running a fan to move air, heating a resistor, etc. This work is what the watt-hour meter measures.

If you have a motor with a bad power factor doing some work. For example: no external load on the motor, but thru bearing friction and windage work is being done. This motor will have a low power factor because it is not doing much work in comparison with its capability. Thus, the inductive excitation current is large compared to the resistive component. The resistive component is a result of the work being done.

Add power factor correction, a capacitor, this will reduce the reactive current as seen looking at the motor and capacitor combination. It has no effect on the resistive component. The resistive component does not change if the voltage, frequency, and load do not change.

An ideal watt-hour meter only uses the resistive component in combination with the voltage to determine energy usage. Improving the power factor does not cheat the power company,

Read thru this whole thread again and see if this has not been said many times.

The post where I provided experimental data with a lamp and capacitor showed that a large change in power factor had no effect on the power reading. The slight increase in power with the capacitor connected was from resistive losses in the capacitor.

.
Well Gar we kinda were thinking not improving but making it worst meaning adding more capacitance into the circuit then needed meaning adding more to see how it would effect the wattmeter ?
Take care
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
090512-0718 EST

ttdezo:

When you run your test with a conventional watt-hour meter it is also important to monitor voltage.

Suppose you are testing a resistive load. If the voltage varies by 4 V relative to 120 V during the test, then an error of up 8% might occur in the measured energy.

I took a quick look at my voltage for couple days.

One day it was within about 2 V, but most of the time within a 1 V range. Sometimes within 0.2 V for many minutes.

On another day it was within about 4 V.

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gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
090512-0844 EST

In doing a Google search I encountered the following:

http://www.power-save1200.com/1200.html
Note the display of UL. Then the display of BBB Online. I have no idea what Reliability Program means.

Admittedly they say UP to 25%, and that does include 0.
Residential customers throughout North America could see a realized savings of 8% - 10% typically and as much as 25% on their electrical usage (and thus power bills). The Power-Save 1200? is UL Certified as the Cat. No. ABET 2201 and CSA certified.

http://www.bbb.org/online/
At BBB on page
http://www.bbb.org/us/bbb-standards-for-trust/
Advertise Honestly
Adhere to established standards of advertising and selling.

Tell the Truth
Honestly represent products and services, including clear and adequate disclosures of all material terms.
The Video at Power Save clearly does not adhere to trust and truth as related to power saving.

There is a real problem with the Power Save advertising and with BBB.

This is an interesting page
http://www.power-save1200.com/1200_specs.pdf
The major component of this device we believe is a pair of capacitors. Yet nothing in this specification about the capacitor size. From ttdezo's post #81 the current to a capacitor at 120 V is 6.25 A. I calculate this to be 19.2 ohms or Xc = 1/(2*Pi*f*C) and C = 138 ufd.

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ttdezo

Member
meter problem.

meter problem.

Guys! Looks like I need to postpone my experiment. I'm having problems with my Ted. Worked just fine until last night when I noticed that green led on the display unit flashing intermittently. Instead of once per second, it flashes in 5-10-15 second intervals. MTU is OK.
I might need to return this unit, we'll see.
Wiring, voltage looks good, don't know what's wrong.
Switched capacitors can cause transient overvoltages, harmonic distortions ....
K8MHz thanks for your offer. I have meters , sockets etc.
Gar, you're right, voltage must be monitored too.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
Checking a bit into the UL listing, here is what the device is listed for:

1.1 The requirements in Part i of this Standard apply to enclosed capacitors with integral protection intended to reduce the risk of rupture and venting of the capacitor enclosure under internal fault conditions.

I guess the assertion that a UL listing meant little or nothing was closer to being accurate than I thought. :mad:
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
090512-2124 EST

K8MHZ:

Thanks for looking up the Power Save UL listing. A good illustration of the marketing tricks companies play with the UL symbol. Nothing illegal but it does not mean anything in some cases relative to the usefulness of a product.

mivey:

Thanks for finding the page on BBB. I think Power Save violates the intent of the BBB. However, in reality the Reliability Program probably does not mean much.


I tried to re-access some of the Power Save pages tonight and some are crashing my Internet Explorer and in turn requiring reboot.

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rattus

Senior Member
The True Believers:

The True Believers:

For those of us who believe what our long dead profs taught us so long ago, we believe that no amount of testing can show home pf correction to be anything but a scam.

First off, we believe that unless the poco charges a pf penalty, there are only miniscule reductions to be had in energy costs. At age sixteen, yes that is right, I was recommending pf correction to our commercial customers. Didn?t understand it then, just doing what I was told.

Second, we believe that the device must be located at the load and must be switched in and out with the load in order to gain any advantage at all. If the device remains connected after the load is removed, it will create losses in the device and in the wiring. It may well increase the usage slightly!

Third, we believe that a single correction device, connected to one leg of a 240V service, cannot possibly correct the pf of a 240V AC unit which would be the main offender in a home.

Fourth, we believe this scam compares to the snake oils, goat gland extracts, and elixirs which claim to cure everything from warts to hydrophobia. BTW, they are still selling bowel cleansing regimens on TV! Maybe they would make a package deal for us??
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
090515-0853 EST

ttdezo:

On the TED system.

To get reasonably good communication from the TED Transmitter to Receiver I could not use the house wiring. So I ran an extension cord from an outlet at the main panel to my Receiver unit. Also I got absolutely no communication if I was on the opposite phase from the TED Transmitter.

If virtually all loads in the house are off I get the repetitive 1 second communication. When some loads are on, I am not sure what, there will be a random variation in the flashing of the receiver LED. Some times a couple second pause.

Where are you located? Are there possibly some people in your area that may have power meters by Fluke, Dranetz, etc. that you might borrow, or get them to help with your experiment?

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ttdezo

Member
test

test

I have another tester. Extech 380976. True RMS clamp on power meter.

Some results.
PS1200 box. L1 - L2 , 6.52A , 0.08KW , 0.79KVAR , Pf 0.98 lead.

Test load, two blowers , flood light, heater with fan. Red with PS1200

L1 , 4.61A , 0.6KW , Pf 0.98 lag , 0.11 KVAR
L2 , 12.8A , 1.52KW , Pf0.99 lag , 0.17KVAR

L1 , 7.7A , 0.69KW , Pf 0.69 lead , 0.7 KVAR
L2 , 13.9A , 1.55KW , Pf 0.91 lead , 0.7 KVAR


A/C just one leg

L1 , 16.3A , 1.43KW ,1.99KVA , Pf 0.75 lag , 1.29 KVAR

L1 , 13.65A , 1.62KW ,1.65 KVA , Pf0.97 lag , 0.36 KVAR

After that I used a residential watthour meter in meter socket with different loads. I measured the rotation time of the revolving disk / 5-10/ with stop watch.
Without exception when Ps1200 was engaged the rotation time decreased ,slightly.
Eg. Ten rotation ; 623 sec. - 611 sec.
561 sec - 550 sec.
Around 2% .
Looks like somehow power factor can influence electromechanical watthour meters. Dan
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
090520-2106 EST

ttdezo:

I have done a quick look at your post.

A/C just one leg

L1 , 16.3A , 1.43KW ,1.99KVA , Pf 0.75 lag , 1.29 KVAR no PS1200

L1 , 13.65A , 1.62KW ,1.65 KVA , Pf0.97 lag , 0.36 KVAR with PS1200
From 1.99 KVA and 16.3 A of the first line I get 122.1 V. This is reasonable. From 1.99 and 1.43 I calculate 1.38 KVAR. Not a good correlation with 1.29 . My calculated PF is 0.719 .

From 1.65 KVA and 13.65 A of the second line I get 120.9 V. Also reasonable. From 1.65 and 1.62 I calculate 0.31 KVAR. Not too bad for correlation with 0.36 . My calculated PF is 0.982 .

With the PS1200 the power consumption went up noticeably and KVA came down substantially. However, KVA is still higher than KW.

The power consumed with the PS`1200 was 190 W higher than without the PS1200. From previous data I might have guessed the power dissipation in the PS1200 capacitors was 100 W and thus 50 W per capacitor.


Your first test:
PS1200 box. L1 - L2 , 6.52A , 0.08KW , 0.79KVAR , Pf 0.98 lead.
has an error in the PF. It should be about 0.101 . My calculation for voltage is 121.2 V. This indicates 80 W of power dissipation within the two capacitors or 40 W within 1. Without looking back I believe with the PS1200 only that the TED power reading was 100 W. TED and this instrument would correlate.


Middle set of tests:
Test load, two blowers , flood light, heater with fan. Red with PS1200

L1 , 4.61A , 0.6KW , Pf 0.98 lag , 0.11 KVAR
L2 , 12.8A , 1.52KW , Pf0.99 lag , 0.17KVAR

L1 , 7.7A , 0.69KW , Pf 0.69 lead , 0.7 KVAR
L2 , 13.9A , 1.55KW , Pf 0.91 lead , 0.7 KVAR
Re-arranging:
L1 , 4.61A , 0.6KW , Pf 0.98 lag , 0.11 KVAR
L1 , 7.7A , 0.69KW , Pf 0.69 lead , 0.7 KVAR

Power increased by 90 W with the addition of the PS1200 because of its internal power dissipation. Without PS1200 the load was close to resistive. Thus, adding the PS1200 increased current, and KVARs as would be expected.


L2 , 12.8A , 1.52KW , Pf0.99 lag , 0.17KVAR
L2 , 13.9A , 1.55KW , Pf 0.91 lead , 0.7 KVAR

This data makes a little less sense. However, we still see 30 W increase with the PS1200.

The above data all showed the 40 to 190 W increase in power consumed when the PS1200 was connected.


The KWH meter does not correlate with the above.

.
 

ttdezo

Member
lag adjusting resistor.

lag adjusting resistor.

Gar ,you're right, some of my measurements are out of line probably due to measuring error. The wire's position inside the clamps and the angle can greatly influence results.
But we like it or not this PS1200 can influence the revolving disk's speed.
Not much, within a certain accuracy range.
If we want to figure it out we have to look at the construction of watthour meters.
Here's a link
http://www.usbr.gov/power/data/fist/fist3_10/vol3-10.pdf
page 12. lag adjusting resistor. This might be the answer. dan
 

ttdezo

Member
A/C

A/C

Another interesting link.
http://powerfactorunit.com/
very skillfully mixing facts with fiction. BUT
Another test today. A/C system , 3 Ton split ,cooling mode,motor load.
20 rotation of the disk , measured in seconds. red with PS1200

184 - 174 , 185 - 175 , 185 - 175 , 184 - 174.

That's it. I guess it would be pointless to deny that this device can reduce the electric bill.
2-5% ,depends on the nature of the load
That's another question , how?
The answer is inside that KWHour meter outside I beleive. Dan
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Another test today. A/C system , 3 Ton split ,cooling mode,motor load.
20 rotation of the disk , measured in seconds. red with PS1200

184 - 174 , 185 - 175 , 185 - 175 , 184 - 174.

That's it. I guess it would be pointless to deny that this device can reduce the electric bill.
Is time taken into account? Is it possible the run time of the A/C system changes so it has to run longer to achieve the same amount of cooling?
 

ttdezo

Member
ac

ac

Temperature was 80 inside the house , I turned down the thermostat to 65 and just started measuring ,PS on -off. AC was running continuously , time difference was very consistent.
We have something else here.
I don't have the necessary equipment and time to prove it, but I'm pretty sure I'm damn right . This so called KWHour meter measures real power at or near
PF 1. When Pf gets lower,it measures something between VA - KW.
That is what PS1200 " inventor " realized, consumers are misled and ripped off.
Home power saver businesses are unchallenged and thriving because unlike utility companies , they don't cheat , they making things right,providing a fair ,legal service.
I wish I could talk with this guy privately.
Of course they can not state " hey you overpaying, do yourself a favor ,buy this gray box"
They had to package their product properly.
Win Win situation. Utilities getting free kvar, environmentally friendly green product, reduces carbon footprint. Costumers paying less plus they have an entry level surge protector. Only drawback is the price. ~ $700 installed.
 
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