Induction Conversion Blade Size Question

[coldspot]

All Induction Conversions-

Flying or have flown

I'm about to try carving a blade set and don't

have any idea of the size required ?

I know the whole system makes a difference but

if I knew a bit more it'll help me with my system,

(thats not quite put together yet).

What I'd really like is for the people that have flown induction conversions to reply to this with a little info-

Induction conversion size =

(HP, single or three phase)

blade size =

(maybe even sizes tried)

System info =

(volts, bank size or tied to, ect.,ect,...)

Maybe even hub setup info =

(how you attached the blade to motor shaft)

Please !!!!!!!!!!!!!!!!!!!!!!!

I'm going to be cutting some wood this weekend and I'd hate to finally carve a blade set and end up with the wrong size!!!!!!!!

I have two Induction Conversions ready-

2 HP 3 Phase units

About done with a 1.5 HP unit also

My system will probebly end up being

12 Volt

Being that I have Flexcharge NC25A-12

(12 V, 25 Amp, without buying more for it)

Also a Oatley # K220 kit

(12/24 V, 16-28 Amp?)

(Amps unknown but in instruction papers they talk about each MOSFET being 11 milliohms rated at 50A, but dissipation at 7 Amps and 4 Amps each)

{Mine has large heatsinks added to the kit.}

Also a few 12 V solar panels.

And a few 12 V Inverters, (5-6)

And battery banks can go 12 V easy.

But

I do have one huge Inverter thats

32. VDC
    
3. ,000W Contin.
   
12. ,000W Max Surge
    
    

(Untested still, was a freeby last year)

Thanks for reading and please leave info if have any!

[wpowokal]

Coldspot, wow can I have some of what you are on, talk about scattered.

Before you carve any blades you need to test your conversion for open circuit voltage. Having found this it gives you your cut in point (speed), it all changes dramaticly once you load it but cut in is the starting point. Posting resistance of windings will allow your full load speed to be calculated, for a given system voltage.

In my experience my conversion cuts in at around 110 rpm on my 24v system, I have the wood but have still to carve the apropriate blades. The set I tested it with were for a much higher operating speed and it stalled at around 15 amps.

You apear to still have to determin what you system is to be, tell us what you require from it in terms of daily load, maximum draw (amps) and maybe some logic can be introduced.

Sorry if this sounds a little critical but your post reads to me somewhat indecisive.

allan down under

[wdyasq]

Allan,

This in only a test post to see if you are a qualified applicant for dental school.

After we pull three teeth, you can tell us if we got the one that hurts.

Thanks,

Ron

[zubbly]

hi coldspot,

i have never really understood blade calculations all that well, and have not really made much of an attempt to refine my blade matching to genny calculations. so what i will do is tell you what works for me, through trial and error, and a lot of gut feeling.

conversions i find like to run fast. using a star delta switch really will get you the best from low and high wind speeds.

TSR-7 is what i carve the most and seems to work very well with conversions. most of what i carve is as close to the USA-35B airfoil as i can make them. http://www.anotherpower.com/gallery/airfoils/usa35b  (compliments of our departed friend Bobn)

i like to use Alton Moore's blade calculator.  http://www.alton-moore.net/wind_calculations.html

what i have done on my last few projects is to enter the blade information into alton's calculator as a 2 blade prop, but carve 3 blades and use as a 3 blade prop. sounds crazy and most of the blade experts will likely agree that it is.  but i have found extremely low wind speed start up and performance levels on the higher speed end excellent. my current 7.5hp conversion uses a 12 foot blade with the 2 blade design and have often achieved 4 kw output with it. another good friend of mine is flying a 1/2 hp conversion with a 2 meter blade set and reported the other day of a 40 amp peak into a 24 volt bank. 30 amp has been common but most of the time 5-10 amp.

an important note on carving. when the width of the blade wood stock is no longer wide enough near the root, "do not" just carve for the maximum angle that the width will allow. re-calculate the proper angle for those last few sections to get the proper angles.

for small conversions, pick your connection that will give you cut in at approx 175-200 rpm (1/2-2hp).  for 3-5 hp, 150-175 rpm.  for 5-7.5hp, 120-150 rpm.

3 phase conversions: 1/2hp-3/4hp-6 foot diam prop

                     1hp-8 foot

                     1.5hp-2hp-9 foot

                     3hp-10 foot

                     5hp-11 foot

                     7.5hp-minimum 12 foot

for lower wind speed areas, increase prop diam.

i have had great success using steel plates to sandwich the blades. i use 1/4 inch steel up to about 10 foot props. "weld on" hubs which are pre-bored to size and have a keyway, i wels to the inner plate. i cut the point off the 120 degree intersections where the blades meet and allow the conversion shaft to slide through the hub and first plate and butt up against the outer plate. i drill and tap a threaded hole in the end of the shaft and put a bolt through the outer plate and screw into the shaft.  its a very solid system.

balance is of extreme importance. balance the assembled prop on a non-converted motor with a very free set of bearings. my personal choice is to use a pendulum weight to balance.  if you look through my album on the irc gallery, you will find pictures of the pendulum weight method.

not a lot of science to the info i gave ya, but it works.

hope it helps you,

zubbly

[wpowokal]

Oh Ron you always do it for me, no body else knows do they! Our secret is safe isen't it.

Alley

[coldspot]

" require from it in terms of daily load, maximum draw (amps) and maybe some logic can be introduced."

Pretty much nothing.

Just trying to get something up to keep the battery banks I have, charged up.

Just going to be a shed/shop that will only need power for lights when I'm there, about 3-4 times a week for about 3-5 hours.(lights= CFL's converted from batteries to 12 VDC)

I'd like to set up a computer (desktop) out there also.

I'll be playing with a few 5"-7" LCD's and cameras with a DVD player also.

Mostly this will be a proof of "It can work".

I'm sick of building, buying and finding the good stuff to just have to put into storage.

Thanks

PS: If it isn't done the HARD WAY, I'm never involved.

[coldspot]

Mr. Zubbly    (In honor of)

Thank you

I was thinking about 8'

I'll try for 9'

Maybe one of each

The info you gave is what I wanted

I've read and reread most all your stuff but didn't take enough notes for blade size.

THANK YOU !!!

"an important note on carving. when the width of the blade wood stock is no longer wide enough near the root, "do not" just carve for the maximum angle that the width will allow. re-calculate the proper angle for those last few sections to get the proper angles"

I'll have to reread this one many times.

I was planning on glue on's to get the extra depth in by the hub. Laminated type of extra wood on the bottom side for about first third of length after the hub set-up that is.

But the first one will be a test with out any extra stuff, I'll get the hang of the carving and then I'll really start to play !!!



PS:

I've hand carved four Archery Bows in the last couple years.

So,I have the basic tools and have a few new ones to help keep the blades equal.

Have a GREAT WEEKEND!!!!!!!!!!!!!

 

[wpowokal]

For mounting the blades we have adopted a method very similar to Zubbly, one point we found was I don't seem to be able to weld the plate true to the hub. So I make that plate 1/2" thick, weld it then machine it back to be true.

We then use this one as one does with the trailer hub in a duel rotor, that is drill and fix 5 lengths of stainless steel althread. The blades sandwitched as Zubbly describes fit over these bolts with nuts front and back, this makes tracking the blades easy. This also means all turbines have the same mounting arangement for blades.

allan down under

[coldspot]

"this one as one does with the trailer hub"

I picked up a split pulley type of thing

that will be great for that trailer hub type of mounting, (5 holes around outer edge), AL metal. But it'll not work for the conversion being 5/8" shaft hole size.

Conversion are 7/8"

 I do have a AMETEK 30 that needs real blades and the 28 Lb stepper also has that shaft size but will require blades a bit longer that the Ametek I think.

Maybe thats where I should be starting with my carving?

Ametek= 2X4's @ 3' each being 6' Blades

Stepper= 2X6's @ 4' = 8' set

Stepper = 2X4's @ 4'-5' = 8'-10' set

Few single phase conversions I've done would be able to use or test any smaller sizes that don't workout for the larger stuff, maybe.

The stepper like the conversions will light up a 1156 bulb to what looks like about to POP,

when spun with a quick flip of the fingers.

But not having any way to test this stuff at set RPM's I don't know the "cut-in" of any of it.

Just that when turned the power is there and enough to be a good start at least.

(PV Panels might like life outdoors better than boxed up storage they see now and the RedRok tracker  

will also! I'm sure) LOL

PS: What I'm "on", Is "R.E.", finally a way to use the degree in "electrical tech", I paid for and suffered going through college 55 miles from home while ending first marrage. Way-back, 20+ years ago!!

[wpowokal]

As PM motors/generators have a linear speed/volts relationship, one mearly needs to hand turn with some kind of crank. Most seem to be able to hand turn at 200 rpm but any speeed will allow the curve to be calculated.

A simple hand crank could be a say 1" sq piece of timber about 6" long afixed to the shaft with a saddle clamp, leave the key in the shaft. Place a bolt in the outer end to complete the crank.

My experience with conversions is they are quite efficient beasts so some design has to go into the blades. As your system will be 12v you may find charging volts reached at relativley low rpm's, there is no facility to "open the air gap" as with duel rotors to allow better matching of generator to blades, ie it may stall.

The Amtech may be a good start, you have the parts, plenty of info on here about them, 6' blades may be a little large (they need speed), but go for it. I use Hugh Piggot's blade program, an earlier version than is currently on his site. It allows you to imput desired watts and speed, then it calculates blade diamiter then gives necessary data for carving. There is nothing wrong with sandwitching the blades between ply as Hugh shows in his books, it's a good way to start.

The set in this photo are like that and actually on a TDM, currently on a F&P. I think about 5', can't measure them they are spinning and it's raining(hopefully this is the breake for the season)

The pre drilled hubs I buy come from bearing supply outlets they are designed for matching to sprockets. Available in a large range of hole sizes with same OD (well in the sizes I use anyway).

[coldspot]

wpowokal-

"pre drilled hubs I buy come from bearing supply outlets"

Any chance of a pic or brand and part numbers?

The Amtek 30 will Fly again tomorrow !!!  

I pulled down its old test tower tonight and will re-set it tomorrow and get some juice from the old ceiling fan blade quick n easy set.

It's Flown many days that way in a real bad location so with better air and maybe even a bit higher up I'll get some power to those batteries.

I might even remember to haul a PV or two out with me and just fasten to shed top for a bit extra.

I checked four of the six, 6 volt ones today and all showed in the high 5.8's.

OOP's hadn't played with them in a month or so.

[wpowokal]

This link will open a PDF file that shows what I use,

http://www.bsc.com.au/perfect/03.PDF

Unless you live in a good wind are you will get much more power from solar than wind, though fortunatly they do compliment each other and wind is more fun.

allan down under

[coldspot]

wpowokal-

GREAT

That pfd will be good for being able to show the people on the other side of the counter what I'm actually looking for.

Never works when you tell them what it really is, so seems better to not tell most of them. lol  

Thank You !!!

This area, (S.E. Idaho)

Is rated a 2 for wind

But it's wrong, I've lived here since birth and the wind is much better than the ratings I've found anywhere on-line.

This is the top end of a huge valley bottom, "The Snake River Valley", and about 50 miles up valley to the real end are the St. Anthony Sand dunes, (The sands of St. Anthony Sand Dunes date back more than 10,000 years ago to the last Ice Age. Dunes up to 400 feet high that move about eight feet each year.How do dunes move?, LOL ), so this means that the wind blows about directly from south to north 90%+ of the time.

The "Wolverine Creek Wind Farm", "http://www.d91.k12.id.us/hawth/WEB%20SITE/lesson%20plans/Web%20pages/WC%2520wind%2520turbine%2520spe
c%2520page.html "is about 5 miles south east of me and I don't think that putting 43 GE 1.5sle wind turbines up is a sign of a low wind area!