Walks-in-Storms' VAWT Project

The only way of increasing the protection of an aerial structure from lightning is to place it in the shadow of a taller structure and bond the taller one to earth. Bonding anything to an earth electrode makes lightning strike more likely, not less.

Thanks sincerely for your interest, but be your comment as it may, law (called building codes) here in the U.S. and Texas require grounding. All homes are grounded, too. I'm most interested in such grounding methods where my alternator is concerned, however.

Thanks again!

I can be wrong but as far as I know -and my knowledge is very very limited- what was mentioned is true so that you should part the problem in 2:

- protection with a higher structure grounded in order to connect to ground the HIGHEST point above your windmill so if an electrostatic field is high enough the plasma channel will go over this connection. there are rules how far over the protected structure the peak has to be. You know I am sure that this protection was developed by an American scientist. If you do not do it the risk is that the big current could burn your generator coils or other components as bearings.

- grounding of your generator in order to protect the house installation and its users.

I am not sure that you will accept my suggestions due to previous discussions but they are sincere since although you were as you were I am not the one to keep it in mind.

I have the Underwiters Laboratories recommendation for lightning protection, as well as a couple of books on home wiring that discuss the matter. I was merely trying here to see if someone might have some other ideas, and ideas more specific than the rather general way the Underwriters' material discusses the problem.

No one seems to deal with small turbines and permanent magnet alternators like mine, in any case. I'm concerned more with induced glow - induction - a lightning strike might precipitate in the stator field. If I ground the pipe above the alternator to the turbine frame (which will be grounded by cable to an eight foot copper-coated rod in the earth), have I accomplished what I need - or is there another way?

I will later have to consider, too, the electical system the turbine serves - battery banks and the rest. I'm just about to get started with those things, and looking for any shortcuts I might come across. Otherwise, I will do my research and learn what I must. That's the fun of things like this for me.

As to the other, I was playing the devil's advocate in order to research for a sociological study and the book I may write. I've learned that certain subjects and manner of speach seem to anger people who would otherwise stay cool, and I'm trying to understand that. I'm also trying to learn how the U.S. Media and Operation MOCKINGBIRD propagandists exploit certain issues (like, for instance, HHO, HHO boosters, and all that). That's all. I never take offense at anything (even, in the past, offense you might not believe), and tend to believe that most intelligent people don't take offense, either. I've seen no reason to believe you're not intelligent, even highly so; neither, you may have noticed, do I ever question anyone's intellect, or resort to insult.

Whatever you might offer by way of contribution to my project (the turbine, I mean), is and will be much appreciated. Lay on MacDuff!

Sorry, I was'nt fully keeping up with your project.

What kind of RPM to wind speed do you anticipate?

Design speed - hoping that my furling mechanism works as my calculations say it will - is 125-150 rpm. Otherwise, the models I constructed ran 484 rpm in a twenty mph wind, and my mathematical calculations indicated angular velocity at 450-550 rpm.

I can't let it go that fast, because it will either tear up my turbine blades, or burn up my alternator - or both.

I think it will tear off part of your roof, especially if it is gusty. An 80 mph gust has how much more power than a 20 mph wind? It increases by the cube, doesn't it? So 64 times more power?

Just a thought. I am sure others can clarify it.

Brian

Thanks for the comment. It's highly unlikely, however, that I'll have any roof damage from anything the VAWT does, inasmuch as it will be just sitting unattached on the roof. The VAWT design results in forces that make it very stable; more, I've designed a guy wiring system into the installation.

We're not likely to have any gusts to 80 mph, either. The maximum I expect on the basis of weather history here is 35, matter of fact. In the event of a hurricane or high winds forecast, I've designed the turbine and its accoutrements to be easily disassembled. I'll just take it down - about a half hour's work.

Thanks again, though, for the reply.

Sorry, I didn't mean the VAWT would damage the roof, but a direct lightning strike will.

There is a house in suburban Melbourne (in Oz) had half its roof blown off (up) through a lightning strike last week, it hit the TV antenna. Made a right mess of things.

I've seen the damage lightning strikes have done to repeater sites, so I guess my advice is to err on the side of caution. Do what ever is reasonable to minimize the potential for a lightning strike.

I agree that you have done your homework on the other aspects of your design, I look forward to further updates.

I think I may have lost track of whom I was speaking to. I certainly agree that a lightning strike might tear the roof off my house. Having worked for more than twenty years as a forensic scientist and investigator (I worked to discover what it was that caused damage, accidents, etc.) for insurance companies, law firms, and state agencies, I am very familiar with the damage lightning can do.

The thing is that not only does there exist an often wide disagreement about how to deal with lightning, my own experience in the matter has me wondering about ways to protect my VAWT. There are a lot of factors, and I'm just beginning to sort them all out - the reason I posted a question here.

I'll figure it out, though; meanwhile, thanks for your comment.

'Hi', Ya all, walking into the body of great minds with my limited intellect is scary, but an isolated lighting rod attached to the rooftop and earth grounded should offer somewhat a limited protection as long as it extended above the turbine be it right, left or on top. We of the older generation have seen many a home saved by such an apparatus..As the man said the higher rod gets the lighting..simple deal, cheat simple solution, Something to think about, look at the transformer set up going into your bungalow, low and behold, an earth ground going to the top of the pole, and a 'lighting arrester with a replaceable link..works for them, should work for you..Wind and lighting both wait for us to try to control and reek havoc on our efforts.. see ya..jim

Jim,

Thanks for your remarks. I originally meant to do just what you suggest here, simply adding a lightning rod to the top of my VAWT tower. Since then, however, I've been wondering what would happen to my stator field windings, were the VAWT and/or its tower to be hit by lightning.

There seems still to be a great deal of disagreement about lightning, and I can't experiment with a lightning strike in order to resolve the matter. I'm going to start (already have, matter of fact) by grounding the mainframe of the turbine (the part in the photo here, plus the frame that holds the turbine) to the house ground to which you refer.

I'm studying the other problem, and readers here have given me a couple of ideas.

Thanks again for your comment.

Let us say that if you DON'T have a lightning rod on the Turbine, the consequences for your VAWT are far worse than if it has one.

So really you have no choice whatsoever in the matter!!!

Yes, that's how I see it, too. Pascale's Wager. I'm searching for the best method, of course and folks here have offered a couple of good ideas I'll consider using.

Thanks for your interest.

There is no "God" proof way of preventing damage to electronic equipment from a direct lightning strike. The level of energy released by a bolt of lightning is measured in Terra watts to the power of God.

That said, you might like to consider "gas discharge" capacitors, these are generally used by phone companies to "protect" the equipment from coronal discharge. Essentially they force a short circuit to ground once the lightning discharge is imposed on the circuit.You would install one between each "leg" of the windings to bonded ground.

I'm an RF techie by trade, and I've had to repair plenty of radio base stations that caught a bolt of lightning. Lightning arrestors can only do so much, and certainly do work. Chances are that if your turbine (which looks pretty speccie) cops a direct hit you will be worrying more about the hole in your roof where the turbine was.

You should consider mounting a coronal discharge lightning rod, these are designed to dissipate the energy of the strike without creating one. It will need to be significantly higher than your Turbine to be effective. Probably around 3 feet higher, and well bonded to ground.

(apologies if I have offended anyone with my references to God)