- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
What is the name of the product?
Home PF Correctin
- Thread starter ATSman
- Start date
- Status
My guess:
My guess:
My guess is that they have hidden a small resistance in series somewhere. A reduction in current would result in a small reduction in power, therefore the meter spins a bit slower.
As long as the caps draw current they will dissipate a tiny amount of power. With no inductive load, the caps will create a leading PF, and with no other load of any kind the caps will create a PF of zero.
It is quite possible that the demonstrator really believes his sales spiel.
My guess:
My guess is that they have hidden a small resistance in series somewhere. A reduction in current would result in a small reduction in power, therefore the meter spins a bit slower.
As long as the caps draw current they will dissipate a tiny amount of power. With no inductive load, the caps will create a leading PF, and with no other load of any kind the caps will create a PF of zero.
It is quite possible that the demonstrator really believes his sales spiel.
weressl
Esteemed Member
The meter IS the 'counter' so regardless how they faked the current reading, you will be paying the meter. The change is about 10%.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Oooo, good trick, I never thought of that!
weressl
Esteemed Member
So, here is the answer:
Take an unloaded motor. Ususally power facor is really lousy at no-load conditions.
If you had an unloaded motor and it had a 0.23 p.f. then if you correct that to 0.92 the currents would be legitimate.
W=E*I*pf and pf=W/(E*I)
W=120*6*0.23=165.6
p.f.=165.6/(120*1.5)=0.92
Of course if you have an additional inductive load wired and you switched that out while switching in the capacitor and even better p.f. of the motor would be possible.
As you load up the motor the power factor would be increasing and eventually go into the leading mode where it would increase the current above the measured 1.5A.
Kartracer087
Member
- Location
- Milwaukee WI
Power factor is basically a measure of how much electricity is being used to create a magnetic field since it ties in with inductive/capacitive loads. Changing the power factor changes the apparent power which is not what a watt hour meter reads. Remember, one watt is a unit of REAL power, a Volt Ampere or Kilovolt Ampere (kVA) is a measure of apparent power which is the combined real (resistive) and reactive (magnetic) component of power. This is why transformers are rated in kVA since they are basically big inductors. So basically this guy is full of it!
weressl
Esteemed Member
Which guy?
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Well, I have been described as being "full of it," at least once or twice,
but I think he means this guy:
weressl
Esteemed Member
Well, I have been described as being "full of it," at least once or twice,
I wasn't sure if you were talking about/to me........
Maybe I need an ego check
... jes kidding, nothing wrong with my ego........Kartracer087
Member
- Location
- Milwaukee WI
I meant the guy at the expo in the original post who said he can sell a device which improves power factor and makes the meter spin slower. I did not mean anyone who posted here on the thread!!!!
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
090320-2038 EST
This afternoon I went to the local home builders show.
Here was a booth with a guy selling one of these power factor correction boxes. This display board had what was probably a capacitor start motor with no mechanical load, his PF correction box, some meters, and switches. Note: two different meters, so these could even be fudged.
I did not have him run the demonstration, I should have.
I told him it was a fraud. He would not get into a technical discussion other than to claim that by improving power factor, which he did claim this was the method being used, that it improved the motor efficiency. And he claimed many satisfied customers. Typical salesman.
What can be done to put this kind of person out of business? It was absolutely impossible to get anything thru his thick head. He probably really knows it is a fraud, but won't admit that fact because he can make money from these sales. No honesty at all.
.
This afternoon I went to the local home builders show.
Here was a booth with a guy selling one of these power factor correction boxes. This display board had what was probably a capacitor start motor with no mechanical load, his PF correction box, some meters, and switches. Note: two different meters, so these could even be fudged.
I did not have him run the demonstration, I should have.
I told him it was a fraud. He would not get into a technical discussion other than to claim that by improving power factor, which he did claim this was the method being used, that it improved the motor efficiency. And he claimed many satisfied customers. Typical salesman.
What can be done to put this kind of person out of business? It was absolutely impossible to get anything thru his thick head. He probably really knows it is a fraud, but won't admit that fact because he can make money from these sales. No honesty at all.
.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
090321-1201 EST
My experiment this morning.
Item tested Shopsmith motor from mid 1950s, 115 V 7 A 1/2 HP continuous duty.
Test equipment Fluke 27 for AC current, "TED" power monitor, 21-25 mfd motor capacitor.
The motor was run for a short time to stablize load. Other than spindle and belt there was no load on the motor.
Measured power without power factor correction capacitor across the motor was 0.410 KW and current ws 7.46 A. Added the 25 mfd capacitor and power was still at 0.410 KW while current dropped to 6.38 A. The capacitor current was 1.17 A. This is additional confirmation that TED is doing a good job of measuring actual real power and removing the reactive component.
Working backwards as a check. The reactive current without the capacitor is 6.63 A and the resistive component is 120 V and 410 W = 3.42 A. With the capacitor the reactive componet is 6.63-1.17 = 5.46 A. The total current calculates to sq-root of (3.42^2 + 5.46^2) = 6.44 A. For a rough check this is close enough to 6.38 for verification.
By adding the capacitor there was a 14% reduction in current for 0% change in the power measured.
.
My experiment this morning.
Item tested Shopsmith motor from mid 1950s, 115 V 7 A 1/2 HP continuous duty.
Test equipment Fluke 27 for AC current, "TED" power monitor, 21-25 mfd motor capacitor.
The motor was run for a short time to stablize load. Other than spindle and belt there was no load on the motor.
Measured power without power factor correction capacitor across the motor was 0.410 KW and current ws 7.46 A. Added the 25 mfd capacitor and power was still at 0.410 KW while current dropped to 6.38 A. The capacitor current was 1.17 A. This is additional confirmation that TED is doing a good job of measuring actual real power and removing the reactive component.
Working backwards as a check. The reactive current without the capacitor is 6.63 A and the resistive component is 120 V and 410 W = 3.42 A. With the capacitor the reactive componet is 6.63-1.17 = 5.46 A. The total current calculates to sq-root of (3.42^2 + 5.46^2) = 6.44 A. For a rough check this is close enough to 6.38 for verification.
By adding the capacitor there was a 14% reduction in current for 0% change in the power measured.
.
Last edited:
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
090321-1401 EST
Larry:
Since power is what is measured and integrated relative to time to obtain KWH this means if the power, P, remains constant that the KWH over some specific time interval, T, will be E = P*T. If there is another time period of equal length and P is the same as before, then the energy over this time is still E = P*T.
The "TED" device is looking to be quite good. I need to see if our fork lift charger provides any large load that I could use as a possible large non-linear load for testing. Also I could use my DeWalt radial arm in a locked rotor condition to get about 80 A at 120 V and fairly inductive.
I have not seen the TED unit to have any zero current drift problem. Meaning DC drift of the zero reading.
This device also has a true real time clock with battery backup. It came with the clock set, and within 1 second of NBS (National Bureau of Standards -- I use NBS because do not like the new name, NIST -- NBS is simpler and rolls off the tongue easier).
Any tests relative to the service entrance meter will come later.
.
Larry:
Since power is what is measured and integrated relative to time to obtain KWH this means if the power, P, remains constant that the KWH over some specific time interval, T, will be E = P*T. If there is another time period of equal length and P is the same as before, then the energy over this time is still E = P*T.
The "TED" device is looking to be quite good. I need to see if our fork lift charger provides any large load that I could use as a possible large non-linear load for testing. Also I could use my DeWalt radial arm in a locked rotor condition to get about 80 A at 120 V and fairly inductive.
I have not seen the TED unit to have any zero current drift problem. Meaning DC drift of the zero reading.
This device also has a true real time clock with battery backup. It came with the clock set, and within 1 second of NBS (National Bureau of Standards -- I use NBS because do not like the new name, NIST -- NBS is simpler and rolls off the tongue easier).
Any tests relative to the service entrance meter will come later.
.
Ass't Lord-High Commish
Member
Checking in...
Checking in...
:smile: Every-so-often I get an email saying someone has replied to this thread and today I decided to see what progress was being made to confirm or deny the validity of these devices.
Despite some great posts explaining everything from PF, KVA, KW to the internal workings of 'old school' meters :roll:, I'm disappointed to see that no real tests showing the effects of one of these capacitive devices in a reactive environment on an old-school meter have been conducted!
What happened to rich000? Didn't they give you one to test?
I wish someone would give me one!
KUDO's to Gar for getting close...but no ciGar...yet!
Checking in...
:smile: Every-so-often I get an email saying someone has replied to this thread and today I decided to see what progress was being made to confirm or deny the validity of these devices.
Despite some great posts explaining everything from PF, KVA, KW to the internal workings of 'old school' meters :roll:, I'm disappointed to see
that no real tests showing the effects of one of these capacitive devices in a reactive environment on an old-school meter have been conducted! What happened to rich000?
Didn't they give you one to test? I wish someone would give me one!
KUDO's to Gar for getting close
...but no ciGar...yet!
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
We had the KVAR display at the shop for a few days. Had 2 meters, 2 amp probes, and a motor. I steered clear of this due to the fact that it only leads to conflict between the owner and myself. I was there early one morning and turned it on. The motor was drawing about 5A and when the KVAR was switched on the motor dropped to about 1.7A. This would be pretty convincing to the layman. (and the owner of our company:roll
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
090322-1258 EST
chris:
Any idea what these "Had 2 meters" really measured? I assume they were supposed to measure power, but did not, or were falsified somehow. Clearly the Amprobes measure current.
Ass't Lord-High Commish:
I am not going to buy somebody's expensive capacitor to prove it won't reduce an electric bill.
The data of my earlier post of 090321-1201 EST is adequate proof that power factor correction does not change the amount of "real" power used. I made an adequate change and that is enough proof.
Admidtedly I gave the salesman that I talked to at the show a hard time, but he is ignorant and is typical of the type that will say anything to make a sale.
He may not know that what he is selling is a fraud, but I really suspect he knows it is a fraud, and that is why he is unwilling to discuss what really happens relative to power factor correction.
Unfortunately his customers are also ignorant. In far too many areas customers fall for testimonials as proof that an item does what is claimed. These customers do not do any independent evaluation of the claims, and unfortunately may not have the ability to do so.
One of the arguments of this salesman was that the PF correction improved the motor efficiency. Total nonsense other than if it changed the voltage at the motor terminals and shifted the motor to a more efficient operating point. Even if the shift was in this direction the improved efficiency would be minuscule. If the test were run so the motor terminal voltage was unchanged and in both cases a pure sine wave voltage was applied, then there would be NO change in efficiency. If precisely the same voltage is applied to a motor with and without a shunt capacitor across the terminals, then there is no change to the excitation of the motor nor internal to the motor and therefore there can be no change to the characteristics of the motor, including its efficiency.
.
chris:
Any idea what these "Had 2 meters" really measured? I assume they were supposed to measure power, but did not, or were falsified somehow. Clearly the Amprobes measure current.
Ass't Lord-High Commish:
I am not going to buy somebody's expensive capacitor to prove it won't reduce an electric bill.
The data of my earlier post of 090321-1201 EST is adequate proof that power factor correction does not change the amount of "real" power used. I made an adequate change and that is enough proof.
Admidtedly I gave the salesman that I talked to at the show a hard time, but he is ignorant and is typical of the type that will say anything to make a sale.
He may not know that what he is selling is a fraud, but I really suspect he knows it is a fraud, and that is why he is unwilling to discuss what really happens relative to power factor correction.
Unfortunately his customers are also ignorant. In far too many areas customers fall for testimonials as proof that an item does what is claimed. These customers do not do any independent evaluation of the claims, and unfortunately may not have the ability to do so.
One of the arguments of this salesman was that the PF correction improved the motor efficiency. Total nonsense other than if it changed the voltage at the motor terminals and shifted the motor to a more efficient operating point. Even if the shift was in this direction the improved efficiency would be minuscule. If the test were run so the motor terminal voltage was unchanged and in both cases a pure sine wave voltage was applied, then there would be NO change in efficiency. If precisely the same voltage is applied to a motor with and without a shunt capacitor across the terminals, then there is no change to the excitation of the motor nor internal to the motor and therefore there can be no change to the characteristics of the motor, including its efficiency.
.
chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
Couldn't tell you Gordon, the owner shows up shortly after I open, and really didn't want to get involved. About a week before this showed up at the office, I was given the KVAR promo package to take home. I went in the next morning and presented my own package, this IMO the most telling post I printed. At that time I thought the battle had been won.
BTW, I heard through the grape vine that TED is developing a 3? model.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
090322-1441 EST
chris:
Yes they claim to be developing a 3 phase unit.
Some further comments on TED.
The 1 second averaging period is too slow to properly measure the effects of most motor turn on inrush. Our motors all start up in a fraction of a second, except my 120 V DeWalt radial arm that takes 3 to 5 seconds because of somewhat over 100 ft of #12.
When I was talking to Energy, Inc. I asked where the product was made. The first answer was the US, then it was stated all components were made in the US and assembly was in the far east. This I questioned becasue it almost certainly was false. But no change in their statement. No need to argue this point. Functionally there is good value for the money.
I opened one of the modules yesterday and the first thing I saw on top of the transformer was made in China.
I would like to see heavier wires and thicker insulation on the wiring to the current transformers. Mechanically these wires are not what I would like in a main panel.
If one combined an oscillating load on the end of a circuit with TED at the same point, then the voltage and power plot would be useful to evaulate the circuit. However, if you get the previously mentioned HP meter, then its plot of voltage could be just as useful.
.
chris:
Yes they claim to be developing a 3 phase unit.
Some further comments on TED.
The 1 second averaging period is too slow to properly measure the effects of most motor turn on inrush. Our motors all start up in a fraction of a second, except my 120 V DeWalt radial arm that takes 3 to 5 seconds because of somewhat over 100 ft of #12.
When I was talking to Energy, Inc. I asked where the product was made. The first answer was the US, then it was stated all components were made in the US and assembly was in the far east. This I questioned becasue it almost certainly was false. But no change in their statement. No need to argue this point. Functionally there is good value for the money.
I opened one of the modules yesterday and the first thing I saw on top of the transformer was made in China.
I would like to see heavier wires and thicker insulation on the wiring to the current transformers. Mechanically these wires are not what I would like in a main panel.
If one combined an oscillating load on the end of a circuit with TED at the same point, then the voltage and power plot would be useful to evaulate the circuit. However, if you get the previously mentioned HP meter, then its plot of voltage could be just as useful.
.
It has been said here and on other electrical forums many times before:
Power factor correction is TOTALLY WORTHLESS on residential applications as the meter measures KwH, NOT KVAR. Residential customers are not charged or penalized for poor power factor in any event.
And 99% of homes do not have enough motor loads that run for long enough to impact power factor anyways.
I am also not convinced that the meters in those demonstrator displays haven't been altered to make the readings what the manufacturer wants them to read.
Snake oil big time.
Power factor correction is TOTALLY WORTHLESS on residential applications as the meter measures KwH, NOT KVAR. Residential customers are not charged or penalized for poor power factor in any event.
And 99% of homes do not have enough motor loads that run for long enough to impact power factor anyways.
I am also not convinced that the meters in those demonstrator displays haven't been altered to make the readings what the manufacturer wants them to read.
Snake oil big time.
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