November 3, 2012

Recall of Champion Portable Generators Sold at Costco

The U.S. Consumer Product Safety Commission announced a voluntary recall of about 8,600 portable generators manufactured by Champion Power Equipment, of Santa Fe Springs, CA. The cause of the recall is gasoline can leak from the generator's carburetor, posing a fire hazard. There have been 11 reports of fuel leaking from the generators, including eight reports of the generators catching fire. The recalled model numbers are 41332 (8250 watt) and 41532 (9000 watt). These models were made in China and sold at Costco.

October 29, 2012

Hurricane Sandy- Interactive Map with Latest Information

Google has created an interactive map for Hurricane Sandy. You can zoom in the map, select a location and find the latest information on the storm location, forecast track, shelter addresses, power outages, and other related data. Just check or uncheck options in the layers menu. You can also switch between a map and a satellite view. And if you lost power, remember- never run a portable generator indoors and in direct rain.

September 28, 2012

Google and Green Renewable Energy

Google is increasingly using renewable energy. Previously they've announced their commitment to carbon neutrality in 2007. They have already invested $94 million in four solar photovoltaic (PV) generators near Sacramento, CA. (See what is PV generator and how it works). These projects have PV systems with a total capacity of 88 MW. Now Google signed an agreement with their utility to supply their Oklahoma data center with 48 MW of wind energy from the Canadian Hills Wind Project.

So, let's do a little math. Depending on the utility's territory, the green power generally costs from 0.5 to 2.5 cents per kilowatt hour more than regular electricity. Assuming the best deal, which is extra $0.05/kWh, each MWh is extra $50. Then 48 MW adds extra 50x48=$2400 each hour. Over an entire year 48 MW of green electricity may cost Google 2400x24x365=$21 million dollars more. In reality, their losses may be less because renewable energy systems rarely work at their maximum capacity. On the other hand, they can be as much as $100 million is they will be charged extra 2.5 cents per kWh. Read more about Google "green" energy activity.

August 20, 2012

China Safety Standard- Higher Clearance for Power Supplies

We used to think that if our power supply design meets IEC or corresponding UL requirements for a given application, we would automatically meet most national standards of other countries. Now, the main ITE Standard in China GB 4943.1-2011 appears to set more stringent requirements to ITE equipment. Although in general, GB 4943.1-2011 is based on IEC 60950-1 2nd addition, it includes certain deviations. Particularly, par.1.1.2 states that unless specified by manufacturer, the equipment is to be used up to 5000m altitude above sea level. Therefore, in the absence of the marking of par.1.7.2.1 specifying the altitude below 2,000 m, the equipment shall comply with the requirements for 5000m altitude. For such equipment, the minimum electrical clearance has to be multiplied by the factor of 1.48.
In many offline SMPS the minimum UL required creepage between primary and secondary circuits is 6.4mm. If both primary and secondary circuits are located on the same side of PCB, this number also determines the spacing (clearance) between the circuits. With the new China standard that goes into effect December 1, 2012, this spacing will now have to be greater than 9 mm. Note that GB 4943.1-2011 will apply to not only the devices for use in the China, but to all those produced there too. So, if you manufacture power supplies in China, in my understanding, you either need to redesign the PCB and replace certain surface mount optocouplers (if any), or add a warning label showing that your PSU is not for use above 2000m.

July 1, 2012

Connecting An Emergency Generator


There are two basic methods of connecting your devices to an emergency power generators:
  • Via a pre-wired transfer switch;
  • Via extension cords.
The transfer switch method can be used for both stationary and portable generators. Portable generators are connected via a manual transfer switch. The stationary standby home systems usually use an automatic transfer switch. It automatically isolates your home from the grid and starts up the generator when it detects a power outage.
A transfer switch installation and wiring requires a licensed electrician and obviously takes time. If you are caught off-guard by a blackout, you’ve got to use a portable genset with extension cords. This is the case today, when more than 3 million people in mid-Atlatic are still without power after a sudden storm. Unlike hurricanes that give you about a week of warning, this storm gave all the impact of a hurricane without any warning. Unfortunately, the extension cords can be used only for cord-and-plug appliances. Connecting lights and hard-wired appliances to a portable generator will not be simple. There are some emergency methods of connecting hard-wired devices, but they may require a professional help. In any case, here are the main two things you need to remember:
  • Whenever you run a generator, it must be isolated from the utility lines;
  • A generator can be run only outdoors with exhaust pipe located away from house.

April 22, 2012

New Proposed Efficiency Standards for Battery Chargers and External Power Supplies

U.S. Department of Energy recently issued Battery Chargers and External Power Supply (BCEPS) Notice of Proposed Rule. DOE proposes amended efficiency standards for Class A external power supplies (EPSs) and new standards for non-Class A EPSs and battery chargers. The proposed standards set the minimum average efficiency in active mode and the maximum power consumption in no-load mode as a function of the nameplate output power. The greatest challenge for SMPS power supply designers in my view will be the proposed limit of maximum power in no-load mode. For EPS below 50 watt it will be <0.1 watt. Since a power supply has to be able to “wake up” when connected to a load, it needs to keep active certain control circuit. Keeping a consumption of an off-line bias supply below 0.1 W will be a real challenge.

The U.S. Department of Energy (DOE) will hold a public meeting on May 2, 2012 to discuss the analyses presented and issues identified in the Notice of Proposed Rulemaking and Technical Support Document. These proposed standards, if adopted, would apply to all applicable external power supplies manufactured in, or imported into, the United States on or after July 1, 2013.

At abote the same time, U.S. Customs and Border Protection (CBP) issued a notice of proposed rulemaking about Consumer Products and Industrial Equipment Non compliant with applicable Energy Conservation or Labeling Standards. CBP will refuse admission into the customs territory of the United States to consumer products and industrial equipment deemed non compliant with the Energy Policy and Conservation Act of 1975 (EPCA).

I feel our government is just one step short of stopping anyone at the border for carrying a cell phone with non-efficiency-compliant charger.

March 15, 2012

Global Warming: No Need to Panic

Recently, Nobel Prize winner physicist Ivar Giaever publicly resigned from the American Physical Society (APS) with a letter that begins: "I did not renew because I cannot live with the [APS policy] statement: 'The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth's physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now.' In the APS it is OK to discuss whether the mass of the proton changes over time and how a multi-universe behaves, but the evidence of global warming is incontrovertible?"

A statement signed by 16 scientists such as William Kininmonth, former head of climate research at the Australian Bureau of Meteorology; Rodney Nichols, former president and CEO of the New York Academy of Sciences; William Happer, professor of physics, Princeton and others says: "...Speaking for many scientists and engineers who have looked carefully and independently at the science of climate, we have a message to any candidate for public office: There is no compelling scientific argument for drastic action to "decarbonize" the world's economy. Even if one accepts the inflated climate forecasts of the IPCC, aggressive greenhouse-gas control policies are not justified economically..."

In a subsequent letter, these scientists noted: "A premature global-scale transition from hydrocarbon fuels would require massive government intervention to support the deployment of more expensive energy technology. If there were economic advantages to investing in technology that depends on taxpayer support, companies like Beacon Power, Evergreen Solar, Solar Millenium, SpectraWatt, Solyndra, Ener1 and the Renewable Energy Development Corporation would be prospering instead of filing for bankruptcy in only the past few months.
The European experience with green technologies has also been discouraging. A study found that every new "green job" in Spain destroyed more than two existing jobs and diverted capital that would have created new jobs elsewhere in the economy. More recently, European governments have been cutting subsidies for expensive CO2-emissionless energy technologies, not what one would expect if such subsidies were stimulating otherwise languid economies. And as we pointed out in our op-ed, it is unlikely that there will be any environmental benefit from the reduced CO2 emissions associated with green technologies, which are based on the demonization of CO2."

February 1, 2012

LushLife® Power Strips Recall




The U.S. Consumer Product Safety Commission, in cooperation with The Container Store Inc., of Coppell, Texas, announced a voluntary recall of power strips made by Lush Life® due to fire hazard.
The recalled strips are brightly colored and have six outlets. Their model number is 8001-6.

Note that Lushlife® disputes these findings and claims their product meets applicable safety standards.

January 24, 2012

Converting Waste Heat to Electricity

A company called Nextreme Thermal Solutions, based in Durham, N.C developed a thermoelectric generator (eTEG) that converts heat directly to low-level electrical power. Their technology uses the Seebeck Effect in which the temperature difference between two metals creates an electrical potential difference. Their generator uses Linear Technology LTC 3108 ultralow voltage step-up converter and power manager chip and can produce voltages up to 5V at power level up to 1 mW on a temperature difference of 15 to 20°K (the temperature difference in Kelvin is the same as in Celsius). Higher temperature gradients will result in higher power. Such devices can be used to feed micropower wireless and battery-free sensors. Unfortunately, the eTEG power levels are not sufficient to increase efficiency of power supplies by recycling heat energy from heatsinks. Also unfortunately, the prices starting at about $500 make this technology cost-prohibitive for regular consumers and hobbyists. By the way, the thermoelectric effect has been known for almost two centuries since Thomas Johann Seebeck discovered that electrical current flows between two dissimilar metals which have different temperatures.