Jump to content

Energy savings math anxiety


Recommended Posts


You will get a kick out of this one.


I recently had a salesman for Power Boss tell one of my customers that if his motor consumed 30kW at full load and 20kW at light load DOL, it would consume 18kW at light load through the Power Boss. I didn't dispute that although I said it was something that should be measured not guessed at, but there is more.


He then went on to claim the 2kW difference was energy savings provided by the Power Boss (true) and that it equated to 40% energy savings! (18/30)? I pointed out that aside from faulty math, he already had saved 33% by just unloading the motor.


He came back and changed his stance, saying that the extra energy he saved was 10% (2/20), so added to the 33% already saved, the total savings was 43% with the Power Boss, compared to 33% without. So the Power Boss was saving them 23% more energy (.33/.43 I guess). I countered he needed some serious re-education at the Math department of his local high school. I pointed out that there was in fact some energy savings, but it is just 6.7% (2/30) of total power. Significant IF proven to be correct, but subject to all the harmonics and heat dissipation issues that come with using that feature etc.etc.


He then went to another of my customers and said that I had confirmed that they could save 40% energy by using his product, because he added my 7% to the 33% already saved again!


I had to threaten him at that point.

"He's not dead, he's just pinin' for the fjords!"
Link to comment
Share on other sites

Typical claims anc calculations of someone who does not understand.


Firstly, I have yet to find a surviving motor with a full load consumption of 30KW and a light load consumption of 20KW. That would imply a shaft load of less than 10KW at full load and therefor an efficiency of less than 30% at full load!!!!!

PLEASE Someone, show me such a motor!!

I had a certified test result from one of these outfits that "proved" that the iron loss of a motor at full load was around 2KW and at no load was around 8KW. I pressed for more detail and was informed that my "theories" were obviously wrong, but no supporting information was forthcoming.

The information in your post is absolutely laughable, but the sad thing is, that there will be some people who will believe it and then learn the hard way.


Have a good day!!

Link to comment
Share on other sites

Hi Hal


I have had a long experience with the enrgy saving concept, being one of the originators of the three phase implementation of the Nola system.

I am happy to comment on the technology and make comments on claims, but I do not offer comment on particular or specific brands.

I believe that it is important to understand the fundementals, but at the end of the day, you need to make your own tests and decisions.


If you have not already done so, I suggest that you look at my paper on energy saving at http://www.lmphotonics.com/energy.htm and also read through some of the postings on this forum.


Best regards,

Link to comment
Share on other sites

I did but I currently interested in dealing with manufacturers of Power Boss and from what I have been reading there performance is questionable I already requested case studies from the company. But I think that jraef and yourself have rised good points in the "Starter Ratings - how are they derived Series", and know I have become overcaution in what I am about the information I am about to receives. So what should I look out for.
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...