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Papers on energy savers.


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#1 marke

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Posted 25 August 2003 - 10:05 AM

I have a paper on energy savers here:
http://www.lmphotonics.com/energy.htm
You can also download it from the downloads tab above.
Best regards

#2 marke

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Posted 25 August 2003 - 10:06 AM

Here is another paper on the energy savers :
http://www.fairfordn...1 Snake oil.pdf
Best regards,

#3 satishrai

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Posted 27 May 2004 - 11:01 AM

[quote]Originally posted by marke
I have a paper on energy savers here:
http://www.lmphotonics.com/energy.htm
You can also download it from the downloads tab above.
Best regards [/quote

Hello......

We are dealing in Smart Motor Controller which can save true energy(Active) up to 40 %.

We wish to share one of our experience with you all.,.

The system is installed in leading automotive company in Spline Rolling Application.

Rating of Motor is 22 kW ABB Make. The running parameters of motor (at motor end) are 426 V, PF= 0.25 , I = 27 A, 5.32 kW (Running Load)

When we installed our system , the PF improves from 0.25 to 0.37 and current decreases from 27 A to 16 A and kW reduced from 5.32 to 4.2 kW.

The best thing what we found that the motor temperature drops from 62.5 Deg C to 49 Deg .

Wish to know more about the product.........please contact

satishrai@nnprojects.com

#4 marke

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Posted 27 May 2004 - 07:23 PM

Hello satishrai

Welcome to the forum.

Can you give more detail on your device?
Is this another Nola derivative, or is it a new concept?
Do you use SCRs to control the voltage applied to the motor?
I think that there are a number of people who would be interested to know more.

Best regards,

#5 satishrai

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Posted 28 May 2004 - 06:22 AM

QUOTE
Originally posted by marke
Hello satishrai

Welcome to the forum.

Can you give more detail on your device?  
Is this another Nola derivative, or is it a new concept?
Do you use SCRs to control the voltage applied to the motor?
I think that there are a number of people who would be interested to know more.

Best regards,


Hello Mark,

Yes we do use SCR's(Back to Back) to control the voltage applied to the motor. This device has intelligence that can monitor the load variation of the motor and hence matches the motor torque & load torque.

The product is so intelligent that it can use the store energy(Kinetic Energy) to save enormous amount of power in some typical applications like Fly Wheel applications.

We know about different products in the market which falsely claims about the True Energy savings.

Mark, I cannot understand about one of the concept which says that you can save energy when Iron Loss = Copper Loss.

Efficiency = Max , when Iron Loss = Cu Loss.

It is not possible to attain this figure.....

Please do tell about this product.

Regards,

satishrai.

#6 cdas

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Posted 15 July 2004 - 03:13 PM

Hi Marke,

I chanced upon your site / forum by chance. What a real eye opener it is. I have recently been in correspondence with a few companies for business tie-up.

Going through some of their claims it made me wonder if the people concerned knew what they were saying or talking about. One company claimed that their "saver" could be used even with high efficiency (eff=0.9 and above) motors.

Yet, the information offered is so well disguised that inspite of my experience marketing similar savers and particularly with such applications, I was really taken in by their claims. Fortunately I read your paper and am able to see the falasy of believing such claims.

I however am left confused about whether the energy saver concept is "science or snake oil".

Although it is true that "only part of the energy that is wasted can be saved", I have applications and sites where the customer/user of such a saver (albeit in specific cases and applications) where the actual number of units (KWh) consumed per month has reduced by 10 to 13 percent compared to the units consumed prior to using the saver. I must state here that the nature of load has not changed during this period (they are producing the same goods and same quantity). Further the units are as recorded by the "rotating disk" type energy meters installed by the Electric supply company. So there is no scope for errors due to non-sinusoidal waveforms as you suggest. Thus the observations are at variance with what has been expressed in your paper.

I however have not recorded the details of the motor characteristics or the actual measured values of the various parameters that were observed.

Not being very knowledgeable in this field I am now left thoroughly confused.

Could you explain where from such a saving could have occured?

I do agree with you however that most people out there are only out to make a fast buck. For this they are ready to go any lengths and make false and absurd claims, which in the long run can only harm the very business they are in and also those who are doing genuine work in this area.

Regards,

cdas

#7 marke

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Posted 15 July 2004 - 07:05 PM

Hello cdas

The technology is certainly not snake oil, and there are definitely areas where savings can be made.
The claims made by some however, are not able to be achieved and those put the whole technology into disrepute.
Small motors operating at very light load for significant periods of time will achieve reasonable savings. The ideal applications are small punch presses and the like where the motor runs keeping a flywheel spining and every now and then, a clutch engages the press itself. Most of the time, the motor is at almost zero load.
Small motors have a full load efficiency as low as 60%, this suggests that recoverable losses at light load may be as high as around 20% of the motor rating.
Large motors have efficiencies of greater than 90% suggesting that the recoverable losses at light load are less than 5% of the motor rating.
I believe that many have witnessed the results on small single phase motors and extrapolated to large machines without an understanding of the motor characteristics and this has led to the false claims.

Best regards,

#8 marke

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Posted 15 July 2004 - 07:15 PM

Hello cdas

Another point to consider, if you take a motor of any size, and run it under virtually open shaft conditions, you will make a significant reduction in the energy consumed, may be as high as 50%, but at that load, the energy consumed will be small compared with the motor rating. For example a 2 KW motor may have losses of around 1.2KW under no load conditions. You could see a savings of say 600 watts or 50%. Compared to full load rating, this equates to 30% and is still significant. (you will only save this energy at zero load, as the load is increased, the energy saved will fall and will usually reach zero before 50% load.)
With a large motor, say a 200KW motor, the no load losses may be in the region of 12KW. The openshaft savings could be as high as 6KW, but relative to the motor rating, this is only 3%. As the cost of the equipment is related to the size or rating, the payback period would be considerably longer. Additionally, the large motor reaches full efficiency at a much lower shaft load than a small motor so the potential to save any energy is restriced to very light shaft loads.

Best regards,

#9 cdas

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Posted 17 July 2004 - 06:34 AM

Hi Marke,

Thanks for your clarification. I guess the confusion arose as I overlooked the fact that you consistently refered to high efficiency motors (which are now becoming more and more common) in your analysis, particularly the higher HP motors operating in 3 phase circuits.

Also the example you have given shows that energy savings are posssible in higher HP motors albeit under specific conditions which need to be carefully evaluated before a recommendation can be made. Definetely, this technology is not a magic wand to save power in every single application as is being propounded by most of these companies.As you rightly said, by making such claims and dumping the "saver" on unwary customers these companies are putting the whole technology to disrepute.

Regards,

cdas

#10 homerjay

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Posted 19 July 2004 - 12:10 PM

Marke & cdas,

you are both quite right. but i think you are somewhat falling into the "marketeers" trap of percentage savings. Percentage of what?... this is a common phrase i use.
I have seen companies state they can save 50% of plated motor rating!!!. I would like to see that when the motor is off load!..... tell me where that technology lies & I will buy it tomorrow! :D

Flywheel presses & large rollers (clay crushers etc) are fantastic applications, especially with our "unique" stored energy feature where we turn the motor off mid cycle!, there is so much inertia in the flywheel or roller that in many cases it can accomodate motor switch off without slowing down.

Im beginning to believe some of the VSD (inverter drive) sales guys are jumping on the energy savings bandwaggon. I was recently at IBM to perform studies on some cooling motors to install soft start/soft stop on them. they have 2 systems identical, one with 4 x 55KW EFF1 motors. and another with 4 x 90KW eff2 motors and VSD's fitted. the VSD system was beand new (the VSD company specified new larger motors and VSD's!!!) and was sold to save 30k per annum of energy. HOWEVER, the motors need to run full speed to keep the cooling system operational. the savings report generated was unbelievable, 30k per annum stated, but how can this be? all the VSD's were operating at 50hz, and how can a 90KW EFF2 motor be more efficient than a 55KW eff1!!!. I took some readings and the 90KW were consuming significantly MORE energy than the 55KW original system.
What annoys me is, the VSD guys get no bad press!

#11 marke

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Posted 19 July 2004 - 07:05 PM

Hello homerjay

I am certainly not a "percentage" jocky. The point ai was making i=with the percentages is that the actual KW is very small. Some quote percentage savings implying that this is relative to the motor size which is very misleading. I firmly believe that you must consider KW saved, not %.

Your point on the VSDs is noted and I totally agree.
In many cases, you will save far more by running the machine efficiently at full speed and then switching off, rather than running inefficiently at reduced speed. It is the same old problem. You will only save energy if the load is a variable torque load and the machine spends a considerable period of time operating at reduced load. It is not the motor loasses that you are saving, it is the machine losses. When the machine is operating at full load with a VSD, the power consumed is at least 5% higher than with a soft starter and to operate continuously at full speed with a VSD is costing more, not less. Additionally, you have to consider the effect of the harmonics on the power factor of the load and the effect that this can have on MDI metering etc.

Oversizing a motor, does not necessarily mean a reduction in operating efficiency, it is not uncommon for a larger motor operating at 75% load to be more efficient than a smaller motor at rated load.
Perhaps you should start a new thread on energy savings with VSD??

Best regards,

#12 homerjay

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Posted 21 July 2004 - 10:35 AM

you are right in what you say, however, there is no way can a 90KW eff2 motor running at some 75% load be more efficient (with inverters fitted) than a 55KW Eff1 at full load with no inverter.

#13 marke

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Posted 21 July 2004 - 11:00 AM

I agree, the motor efficiencies may be very similar, but the losses in the inverter would be high.
Best regards,




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