Power factor correction experiment

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gar

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111130-2116 EST

topgone:

In a residential installation where the power factor correction capacitor is located at the main panel, the kWh meter is within a few feet of the main panel, and the customer is NOT charged a penalty for poor power factor, then theoretically there is no change in the power seen at the meter vs the power to the induction motor load at constant supply voltage resulting in no need for the PFC. There is not enough resistance in the circuit between the PFC and the meter. Further there is no change in the current to the motor to have any effect on the motor.

This can be demonstrated with sufficient accuracy with a small motor, a Kill-A-Watt meter, some suitable capacitors, including one that is sold for residential PFC installation. Certainly with sufficient accuracy to refute the claims of the PFC supplier. My measurements in post #1 demonstrated this.

Now suppose one had to confront a PFC manufacturer in court that their sales method was a fraud or scam, then you have be able to counteract various different arguments they might make. One would be that a bench test was not equivalent to an actual installation. Theory probably is insufficient as an argument. I might agree because maybe the real world conditions are different than the actually application.

My neighbor, now retired, was chief engineer of chassis for Ford light truck. He has told me many times that he had to insist on real world test of components, like oil seals, because many vendors would try to argue that the lab tests were sufficient. In many cases field tests would uncover problems not found in the lab. This did not mean he was against lab tests.

Not quite the same situation in 1931. The father of one of my classmates was a young engineer working in a small group on the development of the first Ford mono-block V8 engine. This group worked in the Edison Fort Meyers Laboratory that at that time was in Greenfield Village and still is. The small steam engine and/or a generator connected to it were used as a dynamometer load. Mr. Ford's desire initially was to use splash lube of the crankshaft as was common at that time. Sullivan thought the engine should really have an oil pump. So in field testing Sullivan had the test driver swing the car from right to left and back as fast as possible while driving down the road. Every engine could be burned out this way. Mr. Ford agreed to the oil pump. The result was that you could drive a Ford V8 from Dearborn to Florida and back at 70 MPH and not burnout an engine. Dyno testing alone would not have resulted in an oil pump in the engine.

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T

T.M.Haja Sahib

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Viability of PFC energy saving

Viability of PFC energy saving

Please see

http://www.samwha.com/fc/tech/tech4.pdf

See also post# 91 where fault level of 22 kv or less is mentioned for residential service 120v/240v.

If the fault level is 22 k,there is practically no reduction in voltage drop due to connection of capacitor of size say,3 kvar . But if the fault level is less say 4 kva (This is not unreasonable considering power supplies in developing countries),there can be considerable reduction in voltage drop.
 

mivey

Senior Member
Please see

http://www.samwha.com/fc/tech/tech4.pdf

See also post# 91 where fault level of 22 kv or less is mentioned for residential service 120v/240v.

If the fault level is 22 k,there is practically no reduction in voltage drop due to connection of capacitor of size say,3 kvar . But if the fault level is less say 4 kva (This is not unreasonable considering power supplies in developing countries),there can be considerable reduction in voltage drop.
So crunch some numbers and show the net savings.
 
T

T.M.Haja Sahib

Guest
Interesting comment. You call me an expert yet don't believe what I'm telling you?

And this that you submitted purports to:

Fanwithatx.jpg


Yet it tells you otherwise.
I straightened it out a wee bit and enhanced the contrast. I hope you don't mind.

Why not try that to convince yourself ?
Of what, I wonder...

As it happens, one of my erstwhile colleagues, who ought to have known better, tried voltage control of induction motors on a test fixture for a client. He used thyristors (called SCRs elsewhere) in an inverse parallel configuration - a W3C arrangement.

It didn't work.
It couldn't.
It doesn't.
 
"What we've got here is a failure to communicate."

Or, more accurately, a failure to understand scientific method. In the usual progression, someone presents their thesis, data, experiment information, and conclusion. IMHO, Gar (and Besoeker) have done this. The next step is for others to discuss the errors of fact or conclusion with their supporting data and conclusions. That essential part seems to be missing, without that it's "proof by blatant assertion". The main (only?) person arguing against Gar and Besoeker's statements seems to be T.M.Haja Sahib, however I don't think I've see him post any relevant data to support the statements made.

Mr Haja Sahib (I hope that is the correct form, my apology if it isn't), please present us with your own data from an experiment similar to that in post #1, or possibly a SPICE model (will etap do this?) for the proposed circuit. That will greatly help the discussion. Please do not direct me to other message without sufficient direction to pull out the relevant points. (If I had a sufficiently accurate power analyzer at hand this week, I'd do a similar experiment myself and present that data.)

Otherwise, we've already discussed a couple of salient matters- measurement accuracy and whether the device will result in a meaningful reduction in power consumption. Everything else, while interesting, is down a rabbit hole.
 

Besoeker

Senior Member
Location
UK
Or, more accurately, a failure to understand scientific method. In the usual progression, someone presents their thesis, data, experiment information, and conclusion. IMHO, Gar (and Besoeker) have done this. .
Thank you, zbang.
Whilst I appreciate your post, I wasn't presenting a thesis. I'm not theorising. Not inventing anything.
Just using well known and reliable tools to calculate what will happen in real life applications.
In a sense, it is no different to the application of Ohm's Law. You don't expect it to be violated.
For sure, there is a bit more number crunching required, but none of it goes beyond a basic circuit diagram and a bit of algebra.
 

topgone

Senior Member
gar:
I do appreciate people scrutinizing details of small things that others don't care investigating. I just kept the idea from other engineers that for residential loads, PFC is insignificant and you have just expounded lengthily the many reasons lately. If all customers will do PFC, it helps the utility, not the consumers, IMO.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Interesting comment. You call me an expert yet don't believe what I'm telling you?

And this that you submitted purports to:

Fanwithatx.jpg


Yet it tells you otherwise.
I straightened it out a wee bit and enhanced the contrast. I hope you don't mind.

Why not try that to convince yourself ?

T.M.Haja Sahib, I think if you were witnessing the Wright Brothers' (inventors of the airplane) first flight in an airplane you would argue with them that their invention couldn't possibly fly and their numbers were all wrong! And as now, you couldn't show them anything done on you own. I think it is time to concede and move on.
 
T

T.M.Haja Sahib

Guest
T.M.Haja Sahib, I think if you were witnessing the Wright Brothers' (inventors of the airplane) first flight in an airplane you would argue with them that their invention couldn't possibly fly and their numbers were all wrong!
:rotflmao:
 
T

T.M.Haja Sahib

Guest
Interesting comment. You call me an expert yet don't believe what I'm telling you?

Yes.Because I am also an expert

And this that you submitted purports to:

Fanwithatx.jpg


Yet it tells you otherwise.

Please reveal it.It may also help the original author also.

It didn't work.
It couldn't.
It doesn't.
Hoist applications utilizing the principle of reducing supply voltage for speed control of induction motor make mockery of your prohibition,sir.Please see
http://www.jpsdesign.com/Portfolios/Hubbell/InstructionManual.pdf
 

Besoeker

Senior Member
Location
UK
Please reveal it.It may also help the original author also.
I thought that you had already got there in post#199

Hoist applications utilizing the principle of reducing supply voltage for speed control of induction motor make mockery of your prohibition,sir.Please see
http://www.jpsdesign.com/Portfolios/Hubbell/InstructionManual.pdf
You realise that this is for a wound rotor machine with an external rotor resistor, don't you?
I already addressed this point in post #177.
 
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