Wind speed / RPM conversion chart?

[Amy]

Some VAWTs have found their way into my possession - https://www.elvwis.com/shop/en/elvwis-disc-generators/56/elvwis-adventure-generator-gea-200-va

They make a potential 225w at 1800 rpm
or 100w at 1200 rpm

What is that in MPH of wind speed?
Before I go to the trouble of making up a frame to mount them all on, i want to know if its likely i will get enough wind for long enough to make it work amongst the buildings in a farm yard


file:///home/amy/Desktop/vawt/vawt1
file:///home/amy/Desktop/vawt/vawt2
file:///home/amy/Desktop/vawt/vawt3
file:///home/amy/Desktop/vawt/vawt4
file:///home/amy/Desktop/vawt/vawt5
file:///home/amy/Desktop/vawt/vawt6
file:///home/amy/Desktop/vawt/vawt7

[Alan D]

Hello Amy

Ref : " Before I go to the trouble of making up a frame to mount them all on "

How far apart from each other will they be.
How high above ground level.
How far will they be away from any shed / wall / hedge / tree / building

They look as though there is not much distance between the top and the bottom bearings.
With turbulence from wind from other turbines  shed / wall / hedge / tree / building
This would cause distortion / instability of the rotor would cause the bearings to wear /
fail quickly.

By design I would have had at least 200 mm between bearings.

[Amy]

Hi Alan

No idea how or where i can site them but have to point out I didnt design or make them, ive inherited them, so the spacing distance isnt something i can do anything about, BUT in the manufacturers website, they detail the spec of materials etc and are a high quality German company, not a chinese back street recycler

[pj]

Farm yard???  What happened to the boat?

[Amy]

Hey PJ
Still aboard, 9.5 years and counting down to a launch day one day never maybe   

The best laid plans of Mice and Men have shirley gone astray, but its cheap living, its freedom, its very afordable, its quality of life, its independence, its perfect for my needs AND it aint bust so im not fixing it....besides, life got in the way and im ok about it. 

[ecogeorge]

My understanding of Vawts is that  unlike Hawts they  cannot exceed the speed of the wind - ie if the wind  is 20mph the outer edge is turning at 20mph.
So you need to calculate the circumference of the rotor......
The 125s model (from your link) has a 32cm diameter rotor
so using  our friend Pi   3.141 x 32 =  100.53 cm circumference .
1 mile = 160934 cms
therefore  theoretically a 5 mph  wind =160934 x 5 = 804670cm /hr  or /60 =13411 cms /min
13411 / 100.53 =133.4 rpm

Taking it farther - 1800rpm (you stated) x 100.53 =180954cms /min        x60 =10857240cms /hr
/ 160934   = 67.46 mph !!!

does anyone else agree ??
George

[Amy]

Thanks George
Im no mathematician so will go with your maths
67 mph wind is gale force and likely to be destructive, and im betting its blustery and never a constant for long, so hardly suitable

The gen isnt at all notchy to turn even with a finger so im wondering if it wouldnt be better to gear it down so a 15 mph wind would give peak generation, or cobble 4 units together on one shaft for efficiency
Maybe some v pulleys and a belt?
ive got 8 units and more to follow
got a bunch of PV panels too

[ecogeorge]

just remember its about circumference of rotor. Obviously an area of rotor is required to catch wind but tall and narrow will turn faster .
Do you have rotors or just generator bits ??
George

[Amy]

If you check out the pics i posted earlier they are complete units with aluminum rotors / 3 vanes and some numpty made a frame to add a top plate to carry a PV panel which is useless and one reason why im taking them off site and being replaced with better tech

[biff]

Amy
     Someone is being very cruel  and planting those
things on you. 1200rpm is a hell of a rev. Even 600rpm is mucho way too fast. Vawts are impossible to balance.
 They very rarely exceed 300rpm.
Hawts are the way forward. You could stick them in the free ads for maybe £30  each and pitch them as PMGs for small scale wind turbines, then invest the profit in a small Rutland or similar. Glad to hear you are getting your hands on more PV. The PV is excellent and trouble free .
      Biff

[Amy]

Im glad you said that Biff because im starting to think the juice isnt worth the squeeze no pun...

They are salvage from a replacement contract, so dont owe me a penny. If i had a river i would strip the gens off and make a water wheel with a v pulley system to run them

There are also a bunch of 15w pv panels, so will concentrate on them

[biff]

Hi again Amy,
            PV is the bee,s knees  but you need amps to progress to the next stage.
   15watt is a good trickle charge for an electric fence battery. So you could  put them onto the Free ads as well and say , " LAST FEW TO CLEAR "
 So at 20 to £25 a pot and you sell a dozen, you could be phoning Navitron office for some real power panels that only need a couple of connections
  Connecting all the 15watt ones will leave you with multiple connections that you do not need 
  As you advertise your PV panels,  you can state that they charge in 24vokt as well as 12volt. You will be able to sell 2 that way. Enjoy,
     Biff