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your paper on energy saving systems is so flawed


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#1 homerjay

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Posted 06 March 2004 - 01:46 PM

ok, you mention in your energy saving document the installed cost of a 1.1KW motor controller is nearly $4000. is this gold plated? does it come with a free holiday to the maldives?

I work for a company that sells such controllers. and our input is as follows.

1) Dont bother selling to a company who only works 40 hours per week, its pointless.
2) the INSTALLED cost of a 1.1kw motor controller (in new zealand dollars at todays exchange rate) is $764
3) selling this at YOUR calculations would give a return on investment of just over 2 years.


Whats your problem?

If your going to produce a written paper & publish it on the net, surely you should get your facts & figures right in the first place?

Now with additional software we have such as stored energy whereby you can turn the motor off for periods on large flywheel presses or rollers, the potential savings are massive. We can soft start a motor in star & then delta, we can turn a motor off after a set period of no load (theres no better energy saver than switching the motor off) plus a whole host of other special applications.

I am the first to agree, I have seen some WILD savings claims in the marketplace, especially at companies who only work 40 hours per week.

If you would be so kind to ammend your paper to reflect the true market price of a motor controller & state its pointless installing it in a 40 hour a week operation.

With Kind Regards

#2 marke

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Posted 06 March 2004 - 08:23 PM

Hello homerjay

Welcome to the forum.

I have noted your comments in regard to the paper and it would appear that your major concern is in regard to the quoted prices and costs.
I agree, things have changed since the paper was written some ten years ago, however the main theme of the paper is that you can only save a portion of what is being wasted. The numbers quoted and savings questioned all come from promotional material of the time.

Your comments in regard to switching machines off when not in use are very valid and certainly provide a better solution than any voltage control solution.

I agree with your comments about selling in 40 hour per week installations, but this is where a lot of equipment has been sold.
I would also add that you should not sell for larger machines, or machines that are undermore than about 25% load, yet I still see the concept sold for large motors operating continuously at 75% load.
The concept that oversized motors waste power is not sound in reality.

Thank you for your comments,
Best regards,

#3 homerjay

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Posted 07 March 2004 - 09:55 AM

Hi Marke,

Indeed, there are some VERY dodgy companies about, one such is a company selling a product called *********** in the UK. the wild claims made by them is somewhat amusing to the trained eye!!!!! and the installations are somewhat mediocre too, however it gives the industry a poor reputation.
One thing i would love to see is good quality competition in this market with reputable companies marketing the product in an ethical manner.
By far our biggest marketplace right now is new control panel builds. the cost for a motor controller is not much more expensive than a star/delta installation. Why in the 21st century companies are still specifying star/delta instead of soft starts i will never know.

#4 GGOSS

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Posted 05 May 2004 - 07:56 AM

Hello Homerjay,

My comments here are not intended as a slur so I hope you don't take them that way.

Over the years marketers of energy saver devices have adopted strategies that are at best described as 'far from ethical'. They have boasted about savings that are both unrealistic and unachieveable and they have targeted distribution partners who could be easilly swayed by the potential of earning BIG dollars. I get the feeling that many of the people that work for or run these companies ex network-marketers. They certainly come accross that way!

Most of the distributors of such devices that I have come accross are not technical or certainly not technical enough to understand the technology, the limitations of thier products and/or the advantages their products have over lets say traditional soft starter products that may include an energy saver feature. Yet they continue to make outlandish claims even going so far as to say (when they know they can't sell you on the energy saver concept) that the soft start functionality they provide is superior to all others on the market whilst offereing 70's style open loop controlled voltage technology against state of the art digital soft start - motor management systems that employ closed loop controlled current technology, linear acceleration & deceleration profiles via torque control strategies and motor protection functionality equivelant to the very best electronic motor protection relays currently available on the world market.

Yes, I would agree with you that there are some out there who are more ethical, more conservative and more knowledgeable. Unfortunately I have only had the pleasure of commmunicating with and/or meeting the 'scammers'.

I sincerely hope the practices of those guys do not adversely impact on you or the company you represent.

Keep up the good work.

Regards,
GGOSS

#5 jraef

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Posted 10 May 2004 - 05:20 PM

Hello Homerjay

I would like to address this part of your post... "One thing I would love to see is good quality competition in this market with reputable companies marketing the product in an ethical manner."

This is of course available all over the place. Many (if not most) soft starters on the market all over the world have the Nola (or some variant) circuit built-in as part of their package. In addition, many very reputable companies got their start in the industry selling the original energy savers back in the 1970's and 80's, only to discover that it was far better to sell the soft starter benefits than it was to foist the energy savings and come out with a bad reputation. Some, like my company, have come full circle now to remove the feature from our products because we found it tended to do more harm than good. When customers buy a product based on unattainable benefits, they become disenchanted with not just the supplier, but also the entire technology. To this day, one of my biggest challenges in the field is to overcome the distaste some users have because of ridiculous claims made by those who came before me.

What has happened more recently is that an epidemic of companies has, as GGOSS has mentioned, begun targeting "distribution partners who could be easily swayed by the potential of earning BIG dollars". This has lead to a proliferation of false claims being made by marginally informed "experts" using dubious science. Mark E's paper is, in my mind, a call to look more closely at the basis of the claims; a clarion of scrutiny available for web surfers who might be caught up in the "If I see it on the web it must be true" syndrome. The age and relevance of the cost figures are less important than the method of getting there.
"He's not dead, he's just pinin' for the fjords!"

#6 cdas

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Posted 15 July 2004 - 01:11 PM

QUOTE
Originally posted by homerjay
Hi Marke,

Indeed, there are some VERY dodgy companies about, one such is a company selling a product called ******** in the UK. the wild claims made by them is somewhat amusing to the trained eye!!!!! and the installations are somewhat mediocre too, however it gives the industry a poor reputation.
One thing i would love to see is good quality competition in this market with reputable companies marketing the product in an ethical manner.
By far our biggest marketplace right now is new control panel builds. the cost for a motor controller is not much more expensive than a star/delta installation. Why in the 21st century companies are still specifying star/delta instead of soft starts i will never know.




Hi Homerjay,

You do have a strong belief in your company and the products it manufactures.
Would you be kind enough to tell me your company's name and where it is located?

Regards,

cdas

#7 cdas

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Posted 15 July 2004 - 01:22 PM

QUOTE
Originally posted by homerjay
Hi Marke,

Indeed, there are some VERY dodgy companies about, one such is a company selling a product called ******** in the UK. the wild claims made by them is somewhat amusing to the trained eye!!!!! and the installations are somewhat mediocre too, however it gives the industry a poor reputation.
One thing i would love to see is good quality competition in this market with reputable companies marketing the product in an ethical manner.
By far our biggest marketplace right now is new control panel builds. the cost for a motor controller is not much more expensive than a star/delta installation. Why in the 21st century companies are still specifying star/delta instead of soft starts i will never know.




Hi Homerjay,

You do have a strong belief in your company and the products it manufactures.
Would you be kind enough to tell me your company's name and where it is located?

Regards,

cdas

#8 Guest__*

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Posted 02 August 2004 - 07:59 PM

Gentlemen,

Your web site BB would be somewhat more credible if you posted information under real names with credible response E-Mails. If you want to be taken seriously then post information with substantive backing and research, we have that, do you?

Our company manufactures and sells these "EnviroStart" products you seem to want to find fault with. We have made significant energy savings without recourse to "outrageous claims" and without misleading or inappropriate statements about the systems we sell.

Perhaps if you looked at the design and use of the products rather than just falling back on the easiest thing in the world, that is to anonymously criticise, then you would perhaps learn and understand the why's and how's of modern motor power control systems and better yourself with improved knowledge. Then, when you know what you are talking about, feel free to comment, but do it from a position of understanding not sublime ignorance.

Jonathan Hughes (Jonathan.Hughes@EnviroStart.com)

#9 marke

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Posted 02 August 2004 - 08:18 PM

Hello Jonathan

Thank you for your comments.
I am surprised that you feel we are cloaked in secrecy etc.
My name is Mark Empson as is indicated at the end of all my correspondence. We do not publish email addresses because they are harvested by spam robots and this is not very beneficial unless you wish to be bombarded with spam, however, contact methods are available on the site. You can send private messages to any registerd poster using the U2U functionality that is part of the forum.

Certainly, I do not believe that we are guilty of anonymously criticising your, or any product. My comments have been made under my name, and no products have been identified. I was one of the early developers of the three phase technology and make comments based on substantial knowledge and research.
My major contention is that "You can only save a portion of the energy that is being wasted". I openly state that the technology does work, but useful results are only achieved in the right applications, not all applications as claimed by some.

We certainly welcome your input and would like to see some good factual results posted here.

Best regards,

#10 homerjay

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Posted 03 August 2004 - 10:05 AM

FAO Mr Hughes

I would be happy to see some of your test results on this site.
Your website only seems to suggest you install in low power commercial applications. Surely, as modern chiller units etc switch them selves off under no load, then no realistic savings can be made?
What companies and applications have you supplied your products?

#11 homerjay

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Posted 03 August 2004 - 11:24 AM

http://www.envirosta...on_Nov_2001.pdf

take a look at the link above,

can a motor controller save between 3 and 14% FULL LOAD on a 200KW slip ring motor?

#12 homerjay

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Posted 03 August 2004 - 05:00 PM

http://www.envirosta...kW_May_2003.pdf

and if we look at this report, it is indicating a 90KW motor OFF LOAD is consuming 80kw without a motor controller & 60 or so kw with.

Is this achievable?
I am led to beleive that motors running over 75% load are pretty efficient. how can a near 20kw loss be achieved at near full load?

>>>Getting confused here<<<

#13 marke

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Posted 07 August 2004 - 02:36 AM

Hello homerjay

Yes I tend to agree. When I look at the graph, if we assume that the mechanical loading conditions are identical in both cases, then there is an apparent saving in the order of 20 KW on a 90KW motor. The indicated loading levels are quite high, but is we assume that within that period there is som time on full load and the rest on open shaft, (When maximum savings will occur) then as we know tha the energy that is saved is essentially part of the iron loss of the motor, it does seem that there is a major problem with the motor. I would expect a motor of this size to be better than 85% efficient, so the iron loss would be less than approx 7% or say 6.5KW. I would expect a saving of less than 3KW max under open shaft conditions, and with a modern high efficency motor, the iron loss should be less than 4KW, so I would expect a saving of less than 2KW under openshaft conditions.

Can someone shed any light on this??

Best regards,

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Posted 13 October 2004 - 10:55 AM

Is it true that the motor must be loaded at least 30% for an energy saver to function properly?

#15 marke

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Posted 13 October 2004 - 05:55 PM

I would say the reverse, the motor must be less than 30% loaded for any appreciable energy to be saved. KW saving is maximum at zero load and reduces as the load is increased, often falling to zero at less than 30% load. This is dependent on the motor size, efficiency, terminal voltage etc.

Best regards,

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Posted 15 October 2004 - 06:59 AM

Thanks Marke, well let me put it this way, while taking a trial of one such Energy saver on our 12.5 HP (440V, 3ph.) AHU motor (one of 10 such motors that we use), the motor started knocking when the saver mode was activated. On measuring the no load current of the motor it was found to be 4.1 to 4.5 A (without saver).The rated full load current of this motor is 18A. The reason the engineer offered for this knocking behaviour was "motor must be loaded between 30 to 60% for the saver to function properly." However the motor has been functiong normally otherwise. Prior to trials the engineer had measured the no load currents on some of the other similar motors to be 6A, and had suggested savings would be possible. Is he correct?

Regards

#17 marke

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Posted 15 October 2004 - 08:47 AM

It is a little difficult to get good stability at zero load and it sounds to me like your supplier has an unstable unit. The highest energy savings will occur at open shaft and reduce as the shaft load increases. The knocking is the energy saver oscillating.
In most reasonable sized motors, the savings to be gained above 30% shaft load are minimal, however the only real way to find out is to try it and see.
The best candidates are motors that draw a high current under open shaft conditions. Perhpas there is some confusion here. The current should be high due to high iron loss, not due to shaft loading.

Best regards,

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Posted 17 October 2004 - 05:55 AM

Hi Homerjay,

We had taken trials of an energy saver on our Power press motor. The motor is 40 HP slip ring motor and the resistors in the rotor circuit are retained (ie. rotor connections are not shorted). The speed and torque were found to drop when the Energy saver was activated. The manufacturer's engineer told us that as the motor was not behaving like an induction motor the Energy saver would not function.

Now three weeks later they have come back stating that they have made some changes to their software and trials taken elsewhere have shown savings of upto 54%(sounds crazy). We fail to understand how minor changes to a software designed for fixed speed induction motor can work successfully with a variable speed slip ring motor? If this is true it should work with any slip ring motor -- rotor leads shorted or not.

Is this technically possible?
;p;

#19 marke

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Posted 17 October 2004 - 06:00 PM

If you are operating your SL motor with resisitors still in the rotor, then you will be wasting quite a lot of power due to the energy dissipated in the rotor.
Adding a Nola style energy saver wil reduce the energy consumed and will cause the motor to slow as well.
For operation at the same speed, the energy that can be saved is only a protion of the iron loss, (same as the standard induction motor) so will be small in KW.

Best regards,




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