Margery Conner Technical Editor Margery Conner's PowerSource streams the latest developments in electronic power design and related technologies.


Profile

RSS Feed

  • Add this blog to your RSS newsreader!

Recent Posts

Recent Comments

Most Commented On

Archives

By Category

Power Management Articles

Blog

Wednesday, August 13, 2008

Confusion may exist about power supplies covered under federal EISA Act

Aug 13 2008 11:50AM | Permalink | Email this | Comments (7) |
Blog This! using:  Blogger.com | LiveJournal |
Digg This | Slashdot This | add to Del.icio.us


I heard from a major power supply vendor that some of its customers believe that the Energy Independence and Security Act (EISA) of 2007 applies to any single output power that provides 250-watts or less of output power. These customers understand the Act as covering "DIN Mount" or "any single-output" enclosed power supply (that is, used for industrial or commercial applications).

Nope, the Act just covers external “wall-wart” type power supplies.

It’s possible that the federal act, which is written in legalese, might be a bit confusing. Better the legal beagles should have followed the example set by the EnergyStar folks, who wrote a very clear description and gave examples of the type of power supplies covered as “external”:

From the EnergyStar website
External Power Supplies
This web site offers information on the continued development of the external power supply specification and test procedure.

About External Power Supplies 

External power supply for WI-FI network router

External power supplies are devices that convert ac power from a wall outlet into lower voltage dc or ac power to be used directly by electronic circuits. External power supplies come in a separate physical enclosure than the end-use product, and usually provide power to the device directly through a separate cord and plug. External power supplies are used to power a variety of electronic devices, including: laptop computers, printers, cordless phones, cell phones, etc.

More than 1 billion external power supplies are shipped per year, and the average American home has five to ten of these components powering devices in their homes. Despite the prevalence and importance of external power supplies, their energy efficiency can often be very low. EPA’s research has indicated that approximately one-third to one-half of the electricity that flows through power supplies is consumed in the power supply itself, as these power supplies are only about 50% to 70% efficient. ENERGY STAR has developed this new program in order to encourage the use of more efficient external power supplies in the market. 

External Power Adapters 
External power supply

What is an Adapter and Why are they Important?

External power adapters, also known as power supplies, are crucial to the operation of virtually all small electronic devices. As many as 1.5 billion are in use in the U.S. — that's about five for every person. The total electricity flowing through all types of power supplies is about:

  • 300 billion kWh/year, and
  • 11% of the national electric bill

They convert high voltage ac electricity from the wall outlet to the low voltage dc power used to power electronic products, like MP3 players, Personal Digital Assistants (PDAs), camcorders, digital cameras, laptops, and cordless and mobile phones.

Earning the ENERGY STAR

An adapter that has earned the ENERGY STAR meets strict energy-efficiency guidelines set by the US Environmental Protection Agency (EPA) and the US Department of Energy (DOE).

  • On average, 30% more efficient than conventional models.
  • Are often lighter and smaller in size, which makes it easier for consumers to transport products like laptops.

Consumers are now able to purchase a growing variety of products that are packaged with ENERGY STAR qualified power adapters. Products with qualified adapters are identified with a special version of the ENERGY STAR label.


Related entries in: Environmental Compliance | Power Sources/Controllers | 


Reader Comments


at 8/19/2008 1:32:40 PM, skylarkbw said:
Enron, Big Oil companies 700%+ per quarter profits, and the government wants to attack wall warts??? What is their problem??? As a tax paying citizen I AM THEIR BOSS, AND THEY WILL GET FIRED AND BLACKED BALLED SO AS TO NEVER GET ANOTHER "PUBLIC SERVICE (READ PUBLIC MASTER)" JOB IN THEIR LIFE. AS FAR AS I AM CONCERNED...THEY ARE AIDING AND ABETTING THE ENEMY IN A TIME OF DECLARED WAR AND SHOULD BE TRIED ACCORDINGLY!

at 8/19/2008 1:47:22 PM, Bill Geist said:
This is usefull information but a better solution would be a switch on the "power supply" so it could be turned off manually and left in place (so it wasn't misplaced). Another solution mught be a "load detector" so it is "turned off when not in use"

at 8/19/2008 4:01:28 PM, Clare Jarvis said:
I agree with Bill Geist. I unplug my wall warts when not in use but this produces unnecessary wear on the plug and outlet.

at 8/19/2008 5:26:25 PM, D. Fritz said:
This issue is poorly presented and really should be better titled. Power supplies drop in efficiency with LOAD, not just because the are plugged into the wall outlet. In power supplies, leakage currents in components and eddy currents in a transformer can cause heat and this may or may not be undesireable. Not all heat is 'wasted'. More to the point, re-provisioning the commercial market is cost added not value added if being done for no other reason than compliance. I throw this red herring into the same bucket as Freon (heavier than air) causing holes in the ozone (a few miles up). Bad science, poorly supported by mostly opinion, and financially a heavy burden for commercial manufacturers to retool for, then a deal breaker when they sell the new products at a higher price to cover re-tooling. Who Gains? Think, please, think!

at 8/20/2008 6:17:49 PM, Rene Jaeger said:
As an engineer I understand that EISA is another poorly planned boondogle cooked up by well meaning beancounters. It falls in the same camp as CCFLs as universal substitutes for incandescent light bulbs. A better mandate would be the inclusion of a switch on power supplies that do not have to remain on all the time and the removal of keep-alive supplies and clocks from equipment that can function perfectly well without them. I believe it is the duty of engineering publications like EDN to inform groups like the US Environmental Protection Agency and the US Department of Energy about the inappropriateness of their decisions and of the disadvantages and dangers of the EISA mandate.

at 8/21/2008 5:14:11 PM, Kamran Kazem said:
D. Fritz is incorrect with his blanket statement that "Power supplies drop in efficiency with LOAD". Incorrect, my friend. It is totally dependent on the type of power supply that's plugged in. In the case of switching power supplies, the efficiency increases with load up to usually about 60%-75% load and then goes down somewhat from there up to 100% load. But even a linear power supply will increase in efficiency from no load up to some fixed load before it goes back down again. Please, let's get our facts straight before making blanket statements like that.

at 9/3/2008 12:50:45 PM, lcsjk said:
The power supply needs an internal switch to turn itself to micropower mode if it is not being used to supply power. A manual switch on the floor behind the chair will not be used. EFFICIENCY: If the ps is 70 pct efficient at 100 watts out it is wasting 30 watts. When the load drops to 1 watt and efficiency drops to 30 pct the power wasted is 0.7 watts. Now if the power supply spends 99 percent of its time at 1 watt, the power supply efficiency needs to be controlled at low power. If it spends 95 percent of its time at full power, the efficiency at high power needs to be controlled, and low power eff may be negligible.

Post a comment


Display Name

Before submitting this form, please type the characters displayed above:


ADVERTISEMENT

©1997-2008 Reed Business Information, a division of Reed Elsevier Inc. All rights reserved.
Use of this Web site is subject to its Terms of Use | Privacy Policy

Please visit these other Reed Business sites

ADVERTISEMENT
You will be redirected to your destination in few seconds.