Thanks Mike.Yes, it is true to hear that alternative power system generations are in progress, and I think it should grow more rapidly than what we se now.

As you mentioned, we all should contribute sharing valuable knowledge about it. Defenitely we will, as and when available.

regards gk

A lot of alternative power systems are advertised in the magazine Solar Today. This is a good resource.

One of these systems is made by Xantrex, which is a division of Durcell. This system mates utility power with a conventional standby generator, a line interactive inverter, a battery bank, and solar cells that can be augmented with wind power. For North American power systems, it comes in 120/240 single phase, 120Y208 3-phase, and 277Y480 3-phase. For 277Y480 3-phase lower voltage inverters are cionnected through a stepup transformer.

There is somebody over at www.eng-tips.com who has one of these and says that it is very handy given that they have frequent power failures. Getting most of the standby power hours from the solar cells and the inverter and only needing to run the generator for heavy loads saves a lot of wear and fuel consumption for the generator. The inverter is both line interactive and generator interactive. The inverter can also charge the battery from either the utility or the generator on cloudy days.

This system is essentially a hybrid car without wheels.

The way that single phase 3-wire and 3-phase 4-wire interactive inverters work is that there is a set of 2 or 3 2-wire single phase inverters with an interconnecting cable(s) that maintain the inverters at 180 degree or 120 degree phase differences.

There is another manufacturer of these systems but I forget who they are and my other computer is not inuse until I have enough energy to upgrade the disk drive and reload Windows 2000.

I am interesting in learning more about educational institution, maybe to become a wind turbine technician, or wind/solar field technician.

Please help to find out.

I was a Solar, wind, and inverter dealer and installer from 1988 to 2003. I did some land base systems, but mostly Boats. Pete's Marine Electric Inc. In 2003 I had to retire because of cancer. I live in the Florida Keys, Key West.

These systems cost big , big money. Yeah you can half a$$ it but that only creates more trouble then it's worth from my experience.

Here is a question. I wonder what good or purpose is accomplished by grounding the negative terminal on of a DC circuit from a photoelectric display? I can see a path for lightning on the structure but fuses and breakers have to be inline DC types. Jack

I need help locating AFCI receptacles to install in a dwelling. Does anyone know where can I purchase these from? thanks

My experience with a southern California windfarm was very interesting. I have described this as one of my forensic cases. especially by what I found to be violations of NEC in the application of Magnetic trip-only molded case circuit breakers, and the worst choice of surge protection: Case 7 - Involved a field of over 60 wind turbine generators. Each generator was driven by a wind turbine, developing power @ 480 volts, connecting to several local grids, and ultimately to the utility. Each squirrel cage induction generator was located at the top of a tower and its output was connected down the tower and into a large electrical cabinet.

An electrical surge developed on the collection grid into which these 60+ generators fed power. During this incident, the surge protection furnished by the manufacturer failed on each of the sixty 480 V electrical panels, leading to many electrical panel fires. No personnel were involved, but the manifestation of the arc was evident in each of the destroyed electrical panels. In each case, the air was ionized around the failed surge device, leading to the destruction of many electrical panels. My study was to determine how that surge was generated, whether the surge protection was adequate and located properly on the 60 electrical panels, and if other protection was adequate

To generate power, there had to be some excitation system, and that was provided by capacitors for each generator, Once running, the capacitors for starting were removed from the circuit, but the grid required capacitors for power factor correction, Control of these capacitors probably led to the unwanted surges, since capacitor switching all three phases simultaneously was undesirable, but necessary.

Each electrical cabinet was independent, but carried the three phases from the grid, with surge protection mounted in the cabinet. The actual surge device was only 0.5 inches in diameter, the size one would expect to see in a radio or some other non-industrial application. The surge device was not only inadequate, but improperly located. Mounting outside would have been safer, and permitted less damage.

Between the individual electrical cabinets and the grids was a molded case circuit breaker with only a magnetic trip function that was set between 8 and 12 times the generator output current. Unfortunately, this device was not rated for interrupting fault current due to the absence of a thermal time-overcurrent component. Of course, the National Electrical Code bans their use in this manner. Curiously, the supplier had a specification sheet that listed that it had an interrupting rating, Mr., Love contacted the Underwriter Laboratory to question how this interrupting rating had been granted, many phone calls were futile, and UL claimed it had not granted that interrupting rating.

After many depositions and meetings with attorneys, the case went to court where the judge told the attorneys to settle this out of court, since there were too many cr

I think one main thing that is needed for wind and solar as more low voltage power is developed is to have very efficient conversion from low voltage DC to high voltage AC so the wire size (and cost) is kept lower. This means we need better high efficiency robust (to EMI RFI events) electronic switching semiconductors and low cost driver packages that can be used as close as possible to the generation location.

I thought you might be interested in a problem my sister had with a photovoltaic installation at her house. For some reason, she bought a 3 KW system even though her house has a peak demand of perhaps half that much. When they tried to feed the excess power back into the utility system, the voltage in her house exceeded 130 volts and the system tripped off. I was not directly involved in the solution, but it appears that this occurred because the utility source impedance was too high. This is an older neighborhood in a climate where few people have air conditioning. --Jim

Mike, Myself and a customer recently attended a seminar for wind turbine generators and are now a certified dealer/distributor for the company. Although the conference was informative, it lacked in what I would call specific and detailed info pertaining to the NEC. Can you give me any info pertaining to install requirements. Our turbine is the SkyStream3.7 (threephase/fourwire/208volt/2.4kw). Thanks, Jeff Snyder

Mike,

Here is the link to the company that put solar panels on 2 of our warehouses. For anyone looking for information on solar panels.

http://www.sunpowercorp.com/About-Us.aspx

if anyone knows a fair price per square ft on a small comercial job please let me know

Please contact me if a training class (or similar) becomes available