bob g

[bob g]

 a parcel of land in kansas in a catagory 5 wind area, property has an excellent ridge with predominant south wind  in summer and north in winter..

will build an off grid small home/shop/greenhouse to live the rest of my life in... at least now i have time to apply what i have learned and design a structure that works with nature instead of against it, cool concept huh, wish i would have done it years ago..

will incorporate wind power, diesel generation, hydro on a limited scale, and will use the utility company as a back up scheme only..

i figure it is easier to conserve or limit my needs for power than it is to either generate or purchase my power, so to those ends the design will incorporate everything i can to limit my needs, but still have most of what modern living dictates.

[RonD]

I've been thinking about what you said about building the windmill and then testing it and then building the perfect alternator.

I think that will work, and I'm going to try it.

I'm not sure how to test it though.

Thanks, RonD

[bob g]

hi Rod and others:

been a while since i was around and a lot has changed here...

as for testing output, we were going to use something called a "prony brake"

it is basically a means of measuring torque on an output shaft at speed.

i figured to make up a test jig on the front of a pickup and run the shaft back over the cab so the blades would be in the clear air..

then with a driver, a hand tachometer and the prony brake one could determine a torque curve for a set of blades over a range of windspeeds and rpm levels.

with this and some math one could determine the optimum windspeed, rpm and loading for any tested blade set.

armed with this information as an example if a blade set produces 500 watts at 20 mph windspeed at a shaft speed of 500 rpm, one could then design and  
build an alternator to more closely fit and operate within those parameters...

i guess i wonder how many good alternator designs are underperforming do to inefficient or undersized  blade sets. thus leaving the builder bewildered and disillusioned. for that matter the inverse could be also happening.. with really good blade set profile that is apparently underperforming because of an alternator not properly matched to the application.

i think maybe you understand where i am going with this.

bob g

[TomW]

Welcome back, Bob. Missed you there for awhile. Kansas, huh? We will be practically neighbors.

Consider this my personal invitation to come chat over on IRC.

Server: otherpower.serveirc.com

Port: 6667

Channel #otherpower

If you don't have a client already try this in your browser:

Click for browser IRC

Cheers.

TomW

[RonD]

I was thinking about just taking a good guess at the magnetic circuit. Then wind a thin fake stator.

Then to test it. I'd set the air gap where I thought it should be, again just make a guess.

Then,,,, Fly the mill and load it with some kind of resistors, say electric fence or power resistors, maybe even an oven control.

This way,, I could find out where (rpm to wind speed) the blades make the most power.

A variable brake switch. If I dead short the PMA the machine will stop, if I don't load the machine it will run away. If I manually load it somewhere in between. I can find that rotors maxium power. Then wind the real stator...

What do you think?

[(unknown)]

your idea is sound and would give some useful information in reguards to where the blades are doing the most work or best efficiency.... but..

it would seem that we have two unknowns with this system..

one unknown we are trying to determine is at what speed the rotor is most efficient or developes best power

the other is how efficient the generator is at that rpm..

perhaps this can be used to get to some useful information , by taking it in steps, first get a good idea of where the blades develope best power output with your generator... then armed with this information, going back and redesigning the generator to operate at peak efficiency or max power in this rpm range..

kind of like developing lapping plates one against the other until the best outcome is attained.

i guess that is why i was leaning toward a prony brake to get an accurate torque map of the blade set being tested.. so as to work out or tweak the performance of the blade profile before i started to design the generator..

anyway i like your idea,, it is a good start toward some very useful information/knowledge... and as they say "Knowledge is Power"  ( hehehe, couldnt help myself on that one)

bob gayle,,, (still trying to find my password)

[Motorhead]

Uhhh I think it's called a pony brake all

[John]

Uhhh, I think not. Do a search for "prony" and you will find that the prony brake was invented by Gaspard de Prony. It was named after him.

John

[Motorhead]

I don't understand why the spelling is so important to you, this device has been in use for three decades as far as I know and it's.Poney Brake, is the terminoligy for it's use around these parts.Something tell's me you you don't know what you want and I'm in interested why you want to use something you don't understand??

Motorhead

[John]

I'm sorry that spelling doesn't seem to be important to you, but in spite of your opinion words do have meanings.

A pony (that is what poney sounds like and it also looks like a typo) is a small horse.

Prony is a name. The term "Prony Brake" gives credit to the inventor and discribes a specific device that separates it from other types of brakes.

Now, just because "Prony" is distorted into "Poney" in your parts does not make it correct, nor does it make it acceptable to the rest of us. Maybe you can help correct the error in your parts by using the correct word instead of just going along with the error?

What ever gave you the impression of what I wanted to use or what I understand?

I know very well what I want.

What I want is to correct remarks that can confuse other readers.

This board has many posts that have a lot bad grammer and spelling but I am not about to try to start correcting them even though it is sometimes hard to read. That is not what this board is for. I do not want to discourage anyone or hinder the free flow of information, ideas, or questions.

But what DOES chap my hide is when someone tries to correct someone who is already correct by using bad information.

Bob was correct when he used "prony" and in spite of your misuse in your parts you were wrong when you corrected him with something that was wrong.

John