A More Efficient Bridge Rectifier?

(solar

panel owners huges sums per kWh. Guess who ends=20

energy

But the liberals dismiss that truth. But then, they deal in myths = primarily=20 just like the conservatives do.

Another myth, flooding all the ecosystems of a useful sized valley does a LOT of ecological damage.

life

experimental

My favorite solution is to reprocess it all into useful stuff. No where all the issues with have been solved, but the vast majority=20 of them are political, with just a few technical ones.

Exactly!

I would guess polyphase forward converters more likely at that power level, but exactly what's used isn't a big deal.

Not at all difficult, we have the technology. It would just be really, really expensive.

The true expense might not be that big a deal, since pole pigs have their own cost. But they last for 30 or 50 years or more, and asking to replace all of them when they're younger than half their design life (on average), that essentially doubles the cost already.

Tim

You need to learn from Rickover's analysis of energy and civilization = from 1957. A link was posted here recently.

By the way, i carry my weight in contribution to society like so many = others here. I have honest and reasonable expectation of being compensated = accordingly.

But life is not fair, but it does tend to piss me off when people who = have never=20 contributed one whit to society, get compensation many times larger than = mine.

nobody

consumption=20

renewable=20

also=20

that=20

suffered=20

and=20

made=20

truly=20

=20

and=20

=20

and=20

based=20

the=20

Jim Yanik wrote in news:Xns9D1FD3F2EEE58jyaniklocalnetcom@216.168.3.44:

Oh,and good luck getting a building permit in residential areas for your wind turbines. HOAs would prevent them,too. and your homeowners insurance would rise because of the liability if the tower collapses and lands on a neighbor's house,or if a turbine blade flies off and strikes something/someone.

No, I don't propose subsidizing clean and renewable energy solutions. At least not any more than other energy sources. Once we add the true cost of obtaining, shipping, using, and cleaning up after crude oil, coal, and nuclear energy, the "green" alternatives will not need so many greenbacks in comparison. There are many hidden subsidies for dirty technology because of the powerful lobbyists of Big Oil and King Coal who make obscene profits while endangering the health of their employees and the general public, and creating instability in much of the world and funding terrorism.

Proper maintenance, safety, and security of a nuke requires many more people with high intelligence, ethics, morality, psychological stability, and effective ongoing training. With the dumbing down of young people in the US, and increasing incidents of violence and mental breakdown and murder/suicide, there is a dwindling and ever less reliable source of trusty personnel. I have personally met at least one employee at a nuclear plant who said some things, in confidence, that were disturbing. I'm not getting warm fuzzies about nukes...

Even here in Baltimore County, Maryland, where wind power is marginal, there are no major impediments to installing wind power (and/or solar):

And residents can purchase electricity from commercially generated wind power at a lower rate than the default BGE and PEPCO suppliers:

I'd rather run the risks you mention than live close to a nuclear power plant that is accident-prone. Oh, wait, I do live less than 50 miles from TMI...

Paul

"By the way, i carry my weight in contribution to society like so many others here. I have honest and reasonable expectation of being compensated accordingly."

"But life is not fair, but it does tend to piss me off when people who have never contributed one whit to society, get compensation many times larger than mine."

You made these statements in reply to my post, but apparently not in response to what I wrote, which follows your comments along with comments of others. So it is unclear to whom you are addressing your statements.

I read Rickover's analysis and it jives with much of what I have believed since first learning about ecology and conservation in 1970, joining the Sierra Club in 1975, and striving to live in an environmentally responsible manner in the 40 years since. I have contributed to society in many ways, and I have not surrendered my soul to obtain overly high compensation while working for any company that is not at least reasonably environmentally friendly.

So I must conclude that your comments were directed to others who fail to take personal responsibility for their part in the rape of the earth, and belittle those who make an effort to live gently upon this fragile planet.

Paul

The IEC specifies extra-low voltage (ELV) below 120 VDC and low voltage (LV) between 120..1500 V, thus it would make sense to use a voltage close to the top of either range, for a specific level of protection requirements.

For instance +/-42 V might be an interesting ELV alternative, provided that the suggested 42 VDC automobile standard (3x14 V battery) is actually going to be common. Due to the low voltage, the voltage would have to be generated in the house, to avoid high losses.

If three phase AC is available and a traditional transformer is used, it is easy to generate 6 or 9 phases and use 12 or 18 pulse rectifiers, with minimal need for PFC.

However, if only single phase AC is available or if a high frequency switcher is used to generate the ELV, then a PFC is required between the mains rectifier and switcher. A building would need only a single PFC, instead of building the PFC into every load.

On the other hand a +/-750 VDC distribution would fit within the LV directive and could carry more power than the current LV AC distribution for longer distances with the same conductors.

Since a traditional 50/60 Hz distribution transformer would be needed to convert the HV/MV (say 20 kV) to the LV AC distribution, why not add some extra secondary windings to that transformer and generate extra phases and use 12 or 18 pulse rectifiers to generate the +/-750 VDC LV, without much need for PFC.

The +/-750 VDC could be used directly for heating applications and devices needing lower DC voltages could use simple square wave DC/DC converters, while only motors would require a VFD. With individual VFDs, the motor starting current could be better controlled, the efficiency at partial load could be improved and motors designed to work at say 50-400 Hz would be lighter for a given power.

Why have LV AC distribution at all? Just make a DC-DC converter operating at high frequency. If anyone really needs 60 Hz AC, just supply an inverter. The automotive types are less than $100/KW.

I agree with pretty much all of that. But there may be safety issues with such high DC voltage, and even 120 VDC and 300 VDC can be deadly. Not from V-Fib as caused by 60 Hz AC, but the fact that is causes muscles to contract and hold tightly which increases the current and stops the heart.

Maybe if the DC supply was floating, it might be safer, but capacitance would cause some shock hazard. Also, DC might be more difficult for a GFCI circuit. But it could be done with a Hall effect sensor - just a bit more expensive and finicky than a simple dual primary transformer or two wires through a CT.

Paul

Where are you going to find enough huge mallets?

On a sunny day (Mon, 15 Feb 2010 10:01:55 +0200) it happened Paul Keinanen wrote in :

In my view DC for in the house would cause problems with switches. The modern switches are based on arc extinction from zero crossing, So you would need solid state switches with EMF feedback protection everywhere perhaps. The other problem with DC is chemical reactions, say electrolysis, causing conductors to be eaten away over time. And just as with AC, switching on loads can create big surges, so your solid state converters will have to be able to deliver all that surge power (if everybody switches on at the same time sort of thing). DC very high voltage systems make sense for long trajectories, say hundreds of kilometres (or miles if you live that far away), but induction losses are low over shorter trajectories, and transformers are reliable. Also now all electric clocks need a crystal, GPS time, or DCF77 :-)

And filling farmland with several hundred wind turbines or solar panels is better?

It would depend where its done. I live in Canada I think there are places it could be done where the impact if done properly could be minimal maybe even provide a net benefit.

There is no way you can generate power without some sort of impact on the environment no matter what technology you use.I'm not just talking the land the technology uses either.

Where do environmentalist think the batteries come from they use for their little mickey mouse home wind farms or solar,the materials they are constructed of? I could go on....

Nuclear by far has the least negative impact with the largest gains in output. Other then the paranoia perpetuated by Hollywood and the mainstream media it is safe when properly implemented "redundancies".

I would be more concerned living in close proximity to a large propane facility run by Ha bib making $8/hr with a grade 8 education.

"Paul E. Schoen" wrote in news:cN5en.79912$ snipped-for-privacy@newsfe09.iad:

Apparently,you're wrong,as if what you posit is true,then alternative energy would already have begun making significant inroads.It hasn't. Despite subsidies.

conspiracy theory. It smacks of the "100MPG carburetor" buyout by "Big Oil". And nuclear is not "dirty". Also,electric cannot replace petroleum powered vehicles. It's just not -practical-.

YES! a GREAT thing to strive for. I note Japan and France manage it.

Thanks to the "progressives"....and their REgressive policies.

you must not have HOAs,then....heck,they won't let people fly American flags. Noise ordinances alone would be a problem,besides building permits.

ISTR that the people around TMI have no problem with living there. They also like the good jobs the place supplies.

I also believe the chances of a homeowner's wind turbine accident are FAR higher than an accident at a nuke plant.They aren't going to do the maintenance,will skimp or put it off.

Oh,didya hear about all the wind turbines that recently FROZE UP in the cold weather and were useless?

Tell me,do YOU have your home wind turbine(s) operating yet???

The subsidies are the specific CAUSE that alternative energy is not making significant inroads. The California initiative alone is enough to guarantee a delay of net energy breakeven by FIFTY THREE years.

See and for detailed analysis.

rote:

ife

al

Some of the technical ones are sort of major. Technetium tends to contaminate the reprocessed uranium and mess up the reactor's stability. Processing plutonium out of the fuel tends to leave the Technetium in the waste material so we can go to a plutonium based reactor.

Another idea that doesn't seem to be getting much work is going over to using Thorium in the reactors. IIRC, it is a proton based chain reaction that would be used in that case. The reactors have to be larger for a given power output and they don't make any weapons grade material in their reprocessed waste.

On Feb 15, 5:57=A0am, Jim Yanik wrote: [.. subsidy to oil ...]

If you count all the security the US provides as a subsidy, you would have to say that oil from the middle east gets a huge one applied to it. If the oil companies had to pay for their own security, I suspect that oil prices would be a lot higher and the oil vs coal trade off would have been favoring coal for all fixed installations.

The good farm land is not a good place to put the turbines. The ideal places for turbines is where there is very steep slopes on the land. This raises the wind speed at the peak and makes it much easier to make a turbine get enough power to be worth building.

The big down side on wind is the fact that the power runs as the cube of the speed. This means you have to design for a peak much higher than the average. This raises the cost.

Up there in the frozen north, solar is a little marginal. Don't you all burn seal oil in your igloos?

Propane would worry me less than some of the other chemical plants. It isn't a poison by nature so you either get blown to bits or smother but you don't die from a 10PPM exposure.

Depends what you are growing.

It is essential to have a smooth surface as possible, in order to avoid slowing the speed of air at 50-150 m as little as possible. A sea around the turbine is a good thing, a plain growing only grass is also a good thing.

Corn, cotton etc. will slow down the air flow. Buildings or trees close to a wind turbine are really bad things.

There is an exception for buildings. There are some projects that are using the high speed wind that goes up the windward side of a building as a way to concentrate the energy for some small scale wind projects. They have a rotor design that is nearly silent.