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Power Factor Controllers


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#41 cnavlekar

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Posted 20 July 2006 - 11:36 AM

QUOTE(mariomaggi @ May 27 2006, 02:04 AM) View Post

Link (not free)

Regards
Mario

Mark ,
I did some work can you see if power saver will work in this case .
Last week I have been to Bearing manufacturing plant and recorded power the work cycle on hydraulic power pack motor every second.

I am a bit surprise to see the very small energy saving prospects on this machine .as test case can you please let me know what would be prospective saving on this machine after putting Somar device.

I am also attaching actual reading set.
Iam anable to attach file properly to this message what is your email id ?

Regards,

CNavlekar






Axial Bore Machine at KOL Motor rating 22 kW 415 V






Seconds
Total kW/Sec
Units in 24.8 Min (kWh)
Units /hr









1
Observation period Total
1488(24.8 Min)
9417
2.61
6.3








2
Consumption <25%
839(14 Min)
1339
0.371
1.59








3
Saving possible @15%
---------------
-----------------------
0.055
0.133 ???????





#42 Tony Welsh

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Posted 08 August 2006 - 08:40 PM

QUOTE(jraef @ Oct 28 2005, 01:17 AM) View Post

Every one of them claim to be vastly different than all the others, no exceptions. They have all supposedly come up with some new microprocessor solution etc. etc. So if you believe them all, what are they all different than? It is all just marketing. The technology behind what they do is all based on the same basic principles outlined in Mark's paper mentioned at the beginning of this thread.
LOL, the Queen's Award. Last I checked, the Queen was not an Electrical Engineer. What Somar got in 2004 was not the "Innovation" award, but the "International Trade" award. Getting that award just means they were successful in exporting something from Great Britain. Other winners of that "prestigious" award exported corduroy fabric, magazines and remanufactured ink jet printer cartridges. I doubt that whatever commission hands that award out in the Queen's name has any idea what it is and what it does.


Fo what it's worth I have seen the award and as i recall it does mention Innovation as well as International trade.

The above says "every one of them...." but I am unaware of any other product which claims to save energy by changing voltage to match load as measured by power factor, a la Nola. Can someone provide details of these otehre products?

#43 jraef

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Posted 09 August 2006 - 02:19 AM

QUOTE
Fo what it's worth I have seen the award and as i recall it does mention Innovation as well as International trade.

From the way I read it, there are 3 categories for which that Queen's award is handed out.
The one that Somar received was only for International Trade, not Innovation.
http://www.queensawa...onal_Trade.html
Here is what Somar won and when;
http://www.queensawa...nners/2004.html
They are NOT on the list for "Innovation" that year or any other year.

QUOTE

The above says "every one of them...." but I am unaware of any other product which claims to save energy by changing voltage to match load as measured by power factor, a la Nola. Can someone provide details of these otehre products?

List of major player soft starters still offering Nola circuit:
Siemens,
GE,
ABB,
Schneider,
Emotron,
Weg,
Saf Canada,
Benshaw, (and brand labeled by several others),
Solcon, (and brand labeled by several others),
Aucom, (and brand labeled by several others),
Fairford (and brand labeled by several others)

Other "big names" are actually no longer making their own products, they are brand-labeleing one of the above, including:
Saftronics (Aucom and Emotron),
Baldor (Fairford),
Magnetek (Solcon)
Teco (Emotron),
TB Woods (Aucom),

Major players in Soft Starters who have stopped promoting the "energy saver" because it caused more customer anger and confusion than satisfaction:
Allen Bradley (although they still sell older versions through Sprecher+Schuh that have it)
Motortronics (and brand labeled by several others)
Eaton / Cutler-Hammer

Fringe players, but still sold primarily as soft starters:
Softac Systems (Canada)
Startco (canada)
Eaco (US, but may be out of business now),
DNH Industries (US)


Companies that have sprung up with the Internet selling them primarily as "energy savers":
Somar (and brand labeled by several others),
Power Efficiency Corp,
Ecopower,
Performance Controls,
SavaWatt
Inumerable Chinese and Indian companies that have yet to start marketing world-wide.

The Nola circuit design is free for the asking from NASA, so anyone who wants into that business can get the engineering documents and away they go, it is no longer "rocket science". What I didn't list are the countless small companies that sprung up in the '70s and early '80s when the promise was still untapped, but who ultimately bombed out when the truth became known. All that is different now is that the Internet has provided wider access to the marketplace which is still full of people who want desperately to believe there is some secret "magic box" that will solve their energy problems.

Want some interesting reading? Check this out, the patent started in 1970 and awarded to Vectrol Inc in 1980 for their energy saver based on the Nola circuit. Vectrol was bought out by Westinghouse, but split off again later to become Motortronics. Note that both Westinghouse (who became Cutler Hammer) and Motortronics have dumped this technology. That should tell you something.

http://www.freepaten...om/4384243.html

If you also follow the link that says "View patents that cite this patent" you will see that a lot of other soft starters and energy savers were based on this basic design.

I should also note that Marke of this very forum was also one of the earliest patent holders for this technology, and HE is no longer convinced that it is worth the effort in most cases.
"He's not dead, he's just pinin' for the fjords!"

#44 marke

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Posted 09 August 2006 - 03:08 AM

Hi jraef

AuCom dropped the energy saving algorithm from there soft starters when they went processor based, about 15 years ago, so they can be dropped off that list.

Emotron do have the functionality built in, but I have never seen it promoted by them.

Two more patents :
http://www.freepaten.../EP0079169.html
http://www.freepaten.../EP0092370.html

Best regards,

#45 Dan_G

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Posted 11 December 2006 - 10:53 PM

Hello JRaef and MarkE,
I'm a researcher/writer for an information service providing information to customer service reps and energy conservation program managers at electric and gas utilities, mostly in North America. We're frequently asked about the validity of motor voltage controllers, and for years have provided responses very much in line with what I've read in the posts on this forum (which I am very glad to have found, by the way!).

I was recently forwarded a case study conducted on behalf of Nevada Power by an outfit called Paragon consulting. They evaluated power draw by two escalators (one going up, the other down) and an elevator in Caesar's Palace casino in Las Vegas. Each escalator is driven by two 20-hp, 3-ph motors, and according to the study, peak load is about 30 kW. The escalators run 24/7/365. With no-one on the escalator, the load is about 6 kW, or about 15%. To make a long story short, the evaluators found that when they put a voltage controller by Power Efficiency Corp. into the circuit, the power draw of the unloaded escalators was reduced by 2 to 2.3 kW. As these motors spend a lot of time at very low load, this level of savings would result in payback of <2 years.

Given everything I've read about voltage controllers, I'm very suspicious of this study. Would you be willing to review and comment on the study? If so, is there a way to forward it to you via this website?

#46 marke

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Posted 12 December 2006 - 09:53 AM

Hello Dan_G

Welcome to the forum.

You can post the study on this forum as an attachment provided that it is not too large.

In terms of the potential savings, this is very dependent on the iron losses in the motors.
If the motor are 15KW each, I would expect that the efficiency would be greater than 80%, typically greater than 85%.
If we assume 80%, then the total loss would be in the order of 3KW, and the iron loss i the order of 1 - 1.5KW
You would only save a portion of the iron loss, so I would suggest that the figure is optomistic.
It is posible that the motors are very low efficiency and that they are over fluxed in the test case (440 volt designed running off 480 - 500 volt).
A exersize that I did recently in response to a "challenge" in regards to claims relating to an over fluxed motor, proved that there was far more saving to be made by replacing the ineficient overfluxed motor with a modern higher efficiency motor (not a premium eficiency motor), than by adding an energy saving device.
The price of such a motor was half the price of the energy saver on my local market. - This has been disputed, but I have he figures. The energy saved was double and the equipment cost was halved.

It will be interesting to look at the study, and if the motors are indeed wastin that amount of energy, then they need to be changed!!

Best regards,

#47 Dan_G

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Posted 12 December 2006 - 08:26 PM

Thanks Mark. Here is the evaluation report I referenced.

Attached Files



#48 jraef

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Posted 12 December 2006 - 08:54 PM

Hi Dan_G,

I know of the issue (although not that particular study), because I have some very close business associations in the Las Vegas hospitality industry. There is a big push going on right now to retrofit escalators with Nola controllers in Las Vegas. Kone, one of the biggest escalator manufacturers, has even recently signed a contract with one of the energy saver manufacturers who has now pulled up roots and relocated their entire company to LV in order to capitalize on the excitement.

From what I have been told, by reputable sources (by that I mean people equally skeptical as myself)) is that this application does in fact save energy, mostly because of the unique nature of escalator applications in Las Vegas resorts. Think about it:

They run 24/7/365, shut down only for maintenance.
The motors must be sized for the maximum load, which is 2 people on each step.
Their load profile is very sporadic, short periods of high load (i.e. when a show lets out), followed by long periods of comparatively light or even no additional load other than the normal friction.

What makes this somewhat unique to Las Vegas is the use profile, the 24/7/365 issue, as well as a "perception" issue of being accommodating to their customers. In department stores and office buildings, escalators can be shut down for long periods of time each day when there is no potential for traffic and when they are in use, the usage is relatively constant. In Las Vegas, the casinos and resort facilities rarely close (if ever) and in fact, they encourage the 24 hour nature of the environment, as well as emphasize the "luxury" of having every convenience available to you whenever you want it. One of their other unique issues is to NEVER inconvenience customers in any perceptible way, because they don't want to give them even the slightest excuse to go next door. So that means you can't turn off escalators at night or when not seeing heavy traffic. Combined with the mild weather that allows them to have quite a few outdoor escalators as well, there are 1000's of escalators in that city, even over 100 in each of several of the larger resorts. As a result, if they can save even a small amount of energy during light loading times, it adds up to big money for them, and we all know that Vegas is all about money!

This issue has been a bigger deal ever since 9/11 when the Vegas traffic dwindled for a short time and they actually started paying attention to their operating costs. Right after that I did some work on trying to come up with a VFD application on a test escalator for one of the casinos. We slowed the escalator to a creep, but when someone got on, we detected the added load and slowly ramped it to full speed; slowly so as to not make the user fall! What we found out was that people will not get on to a slowly moving escalator! They apparently perceive it to be "broken" and stay away from it. That caused panic with the casino managers!

So the bottom line is, because of the somewhat unique aspect of the Las Vegas environment, this may in fact be one of those few applications where the Nola controller makes sense. Once they saturate that market, I expect we will see them try to use that example as justification for every escalator on the planet even though the unique conditions that make this viable will not necessarily apply.

That said, don't neglect the issues Marke brought up. If you investigate and find that the motor is not running inefficiently when unloaded, even the Nola controller won't help much.
"He's not dead, he's just pinin' for the fjords!"

#49 Dan_G

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Posted 12 December 2006 - 09:11 PM

Thanks very much JRaef.
If there is a good energy-saving application for voltage controllers, this would seem to be it--long operating hours at very low load, as you point out. Thanks for validating that this appears to be a good application.

The project you mentioned applying a VFD to an escalator sounds very interesting. Did you or anyone else write up a report on it?

#50 jraef

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Posted 13 December 2006 - 12:36 AM

No, I don't typically document my failures!
Although technically it worked from an electrical standpoint, we completely missed the psychological aspect of escalator use. I have mentioned that fiasco to a couple of elevator guys I've met and they laughed. They could have predicted that outcome themselves without testing. There apparently have been experiments in the past with using proximity sensors to anticipate someone approaching an escalator with enough time to turn it on and get to speed. The problem was, people just don't approach an escalator that isn't already moving.
"He's not dead, he's just pinin' for the fjords!"

#51 marke

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Posted 28 December 2006 - 08:54 PM

Hi Jraef

A couple of years ago, I did an escalator instalation with a VSD and a light curtain. When the escalator was empty, it ran at 10% speed. When someone approached the escalator (detected by the light curtain) the escalator accelerated to full speed, so by the time the passenger got onto the escalator, it was almost at full speed.
This seems to have the desired effect.

In travelling around Europe, I have found it is common at airports to stop the escalator when it is not in use and start when a passenger approaches.

The subject of energy saving has been discussed at great length, and there are applications where the losses in the motor are higher than the mechanical losses, but in many applications the mechanical losses are far higher than the electrical losses and the best means of saving energy is to either slow the machine or stop it completely. I am not sure of the magnitude and source of the losses in an escalator, but suspect that there would be a reasonable level of frictional loss suggesting that slowing or stopping would provide a better result.

Dan_G
Can you please re post the attachment, it seems to have got lost in the migration between servers. ( This forum has been moved from it's original server to a new one and in the process a few messages have got lost)

Best regards,

#52 jraef

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Posted 30 December 2006 - 06:25 AM

Hi Mark,

10% creep speed, now that was a good idea. Wish I had thought of that! It would likely get around the psychological issue of people not bothering to approach a non-moving escalator, but still reduce the power consumption during non-use.
"He's not dead, he's just pinin' for the fjords!"

#53 Dan_G

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Posted 08 January 2007 - 09:44 PM

QUOTE(marke @ Dec 28 2006, 01:54 PM) View Post


Dan_G
Can you please re post the attachment, it seems to have got lost in the migration between servers. ( This forum has been moved from it's original server to a new one and in the process a few messages have got lost)

Best regards,


Hi Marke,
Happy New Year! This is the first I've logged on this year, so sorry for the delay. I tried to post the attachment, but I get an error message that the 428 kB file is too large. I'll send it to you separately for you to post.

#54 CadTech

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Posted 20 April 2007 - 01:38 PM


Is this product the same as those that have been written about here? (which appear not to work as advertised)

http://www.pwgtech.c...-overview.shtml



#55 marke

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Posted 21 April 2007 - 01:29 AM

Hello CadTech

Welcome to the forum

Well, what can I say, just more of the same!! You can only save a portion of the energy that is being wasted.
Quantify the energy wasted in the motor and that sets the order of magnitude. At very light load you will same a higher percentage of the losses than at a higher load.

Have a good day
Best regards,

#56 jraef

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Posted 23 April 2007 - 05:47 AM

QUOTE(CadTech @ Apr 20 2007, 06:38 AM) View Post

Is this product the same as those that have been written about here? (which appear not to work as advertised)

In a word, Yes.

"He's not dead, he's just pinin' for the fjords!"

#57 gentlesun

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Posted 24 April 2007 - 01:54 AM

Hello !
Now , efficiency of motor is higher than the past , Can the PFC work worthly?

#58 marke

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Posted 24 April 2007 - 06:50 AM

Hello gentlesun

welcome to the forum

If you are referring to the Nasa style energy savers commonly refferred to as power factor controllers, then the energy that can be saved is reduced due to the lower losses.

If you are referring to power factor correction, then there is no change as power factor correction will not give any appreciable energy saving to the consumer.

Best regards,

#59 jraef

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Posted 04 May 2007 - 07:40 PM

Hi everyone.

I thought you might find this article interesting.

http://www.chuck-wri...werplanner.html

Here is a quick excerpt just in case his site eventually goes down. This guy bough an "energy saver" called the Power Planner, and did some decent recording and observations on domestic appliance usage.

QUOTE
... I decided to buy the gizmo and try it out on my refrigerator, a late model KitchenAid with a high efficiency rating. I have monitored operation of the refrigerator for some period of time, and find that when it starts, it draws about 146 watts, decreasing to a steady state of about 130 watts. I measured the power using a Brand Electronics digital power meter. This instrument measures true power by measuring both the voltage and current, and multiplying their waveforms to determine the power waveform. Over a period of days, it estimated a monthly operating cost of about $2.80. (5-1-01 - this assumed $.08 per kwh, so the fridge uses about 35 kwh per month, or 1.17 kwh per day. At 130 watts when running, it must be running about 9 hours a day, or a third of the time).

Using the Power Planner, I can detect no difference in the power consumption of the refrigerator. Whatever the Power Planner is supposed to work on apparently doesn't exist with my refrigerator.

I decided to try it on my solar water heater, which has two pumps that together draw about 151 watts.

I plugged in the PowerPlanner and read 151 watts. Then a few seconds later I heard a change in the sound of the motors (more hum, which is funny, because the PowerPlanner literature asserts that it makes motors run more quitely), and suddenly read 147-148 watts. So, I suppose it works. It will save me about 2.3 percent. Assuming the water heater pumps run 8 hours a day, this amounts to 6.7 cents a month. It will take me about 50 years to pay back its $40 cost. ...

"He's not dead, he's just pinin' for the fjords!"

#60 Macabenta

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Posted 27 March 2008 - 05:23 AM

QUOTE (marke @ Aug 19 2003, 03:37 AM) <{POST_SNAPBACK}>
Hello Area

The energy saving concept is to reduce the voltage applied to the motor when it is operating at less than optimum efficiency in a manner to cause the operating efficiency to increase.
Reducing the voltage applied to a motor will reduce the magnetising current (inductive) and the iron loss (resistive) but will increase the work current (resistive).

So the bottom line is, yes there can be a reduction in both the KW and the KVAR. Under part load conditions, it is also possible to have a net increase in KW with an effectrive increase in copper loss due to the increased "load" current.
As you are only interested in KW savings (as most people are) the savings are generally very small relative to the motor rating and are highest on small motors at zero load. Many of the marketers involved in this technology quote percentages rather than watts, and you can save say 40% of the open shaft losses of the motor, but this is still very small relative to the motor rating.
Please rest assured, I do know the difference between active and reactive power. All the figures that I quote and use are true KW figures (active power), not KVA. I can not vouch for some manufacturers figures though.

If you are looking to justify the use of the technology based on watts saved, only look at small motors operating 24/7 with significant amounts of time open shaft. i.e. punch presses, plastic granulators etc.

In terms of your quoted example, my comments are:
[list]
[*]At 47% load with a 75KW motor, I would not expect to se any saving at all, certainly no significant saving
[*]In my opinion, you will not increase the efficiency above the rated full load evviciency, and I would not expect to equal it.
[*]I would not expect the power factor to exceed or equal the rated full load power factor
[*]You can not calculate the power consumed when the energy saver is operating based on measured voltage, current and power factor. The current in non sinusiodal and the normal formula do not work.
[*]Results must be measured on quality 3 phase metering equipment designed to operate with non sinusoidal waveforms.
[list]
I believe that you are right to question data claimed for many of these applications. Much data that I have seenover the years has been obviously "created" by people with a very poor technical understanding.
If we look briefly at the motor quoted, 75KW with a maximum efficiency of 94.5%, then at full load, the losses would be in the order of 4.3KW Of this, I would expect about half to be iron loss, say 2 - 2.5KW and under very light load conditions we may say 40% of this which is going to be in the order of 1KW. As the load is increased, the power saved will reduce.
I would never consider or expect to get real power savings unoless the load is light and the efficiency is low. I usually use a power factor of less than 0.4 as an indicator that there may be some potential to save energy.
I would expect that the figure of 0.7kw is very unlikely based on the above.
Best regards,






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