First propeller turns of my 600W wind turbine

[Remundo]

Hi Looping,

20 W ... this is a modest start ... Maybe everything is not yet settled. When say 600 W, what is the wind speed?

Maybe also check the quality of your generator and if your wires have sufficient diameters ... You can quickly transform a wire into a radiator if its section is too small.

Good luck and ... good luck

[loop]

hi Remundo

I didn't measure the wind speed because I don't have an anemometer
I used the weather chart from France to announce the speed
600W is the maximum power of the generator given by the manufacturer
Below is the power curve as a function of wind speed and rotation (I'm very far from it!)



For the losses in the conductor wires, they are reduced since I transport the three-phase AC current to the rectifier bridge

A+

[Remundo]

Based on 20 km / h, that's 5,5 m / s. Based on your data, that's 114 W according to the table ...

Compared to your 20 W, there is something wrong

[Other]

Hello

18 volts at no load is not very high
when you make it flow into a 10watt lamp does the RPM decrease? did you measure the voltage at the lamp?
It is easy to measure for the RPMs since as you go down in alternative, you measure the frequency with a Fluck
Even you can put an old RPM of WV jetta or Golf they are connected to the AC of the alternator.

Try to run it on a lower wattage lamp, see if you can get your 12 volts.

In reality these generators are regulated by the battery which makes a buffer the faster it spins the higher the voltage but as the battery absorbs the amperage it is regulated around 15 volts
Like the old battery charger.
The generator you should have tested it with a variable drill to see the flow and the necessary force and also how the voltage evolves.

the other test when there is wind try to make it deliver to the maximum whatever the voltage a low resistance see even a momentary short circuit with a piece of wire 1mm, this way you check if your propeller is able to ( catch the wind) the RPMs should drop a lot.

At a glance the (pitch) not seems important to me so low RPM and efficiency only in very strong wind.
a propeller once it turns it's plus two small blades in the wind it's a complete disc.

Andre

[loop]

Hello

Reply to Remundo

Compared to your 20 W, there is something wrong

I know
The manufacturer of the wind turbine offers a 5-blade propeller of 1.8 m in diameter
I prefer a 3-blade solution (less work) with a larger diameter, 2.1m which should have turned a little faster with a larger catch area and a higher lambda for light winds

For information here is what I deduce from the manufacturer data

at 230 rev / min = 3.83 tr / sec the blade tip travels 1.8 x 3.14 = 5.65 m
The linear speed of the blade tip is therefore 21.64 m / sec
The input wind speed according to the table is 3.2 m / s
Or a lambda at the start of the load of 21.64 / 3.2 = 6.76, which is high for a 5-blade propeller

For 7 m / s R = 310 tr / min lambda = 4.17
For 11 m / s R = 340 tr / min lambda = 2.91

The propeller being designed according to an optimal lambda and therefore a chosen wind speed, we see that the efficiency cannot be the same over a wide range of winds.
My propeller was "calculated" for a lambda of 5.6 at the start of the load, ie 230rpm and 14.2V for 4.5m / s (16 km / h)

Response to André

18 volts at no load is not very high
when you make it flow into a 10watt lamp does the RPM decrease? did you measure the voltage at the lamp?

I made the rectified current flow on a 12v 20W bulb and indeed, this slows down the rotation (we draw mechanical power in the form of resistant torque in the rotor)

the other test when there is wind try to make it deliver to the maximum whatever the voltage a low resistance see even a momentary short-circuit with a piece of wire 1mm, this way you check if your propeller is able to ( catch the wind) the RPMs should drop a lot.

Indeed, if I cause a short circuit, the rotation suddenly decreases and the rotation becomes very slow

At a glance the (pitch) not seems important to me so low RPM and efficiency only in very strong wind.

At the end of the blade, the profile is almost in the plane of rotation
It is at an incidence of 6 ° compared to the relative wind calculated on a lambda of 5.6
No load, the speed of rotation is normal, which indicates a good lambda when empty, but as soon as the rotor is braked (start of load for example) the slip is too great to maintain a sufficient speed of rotation
Maybe I need to further refine the finial at the end of the blade because my NACA 4412 is not suitable?

A+

[Cuicui]

Hi Looping
Hats off for your wind turbine!
Is the pitch of the blades adjustable? If so, it would be interesting to experiment with different pitch settings.

[Other]

Hello

Maybe I still need to refine the frofil at the end of the blade because my NACA 4412 is not suitable

?


If I do the comparison on an airplane, the diameter of the propeller is very important,
for a given motor (a rough rule for the usual diameters) at each increase of 1 "in diameter (25,4mm) it is necessary to decrease the pitch by 1" 25,4mm
the energy captured with a propeller decreases rapidly with the diameter and not linearly
A 100hp Continental engine has difficulty turning a 1,90m propeller while it easily turns a 1,70m propeller

In a propeller, you don't just have to look at the speed at the end of the blade, the diameter is directly related to the power, the pitch directly related to the wind speed, the width of the blades related to the torque.
The multi-blades yield decreases, the tri-blade has the advantage of generating less vibration.
Theoretically it is a monopale which has the best performance
with a counterweight
A propeller must take care of the last 1/4 of the tip of the blade, the rest is very tolerant on the profile and on the pitch, a profiled oval bar would do the same thing, (Hélice Hartzel) it is nothing but the part that turns quickly that interests us.

An airplane with a large propeller, when you reduce it in descent, it is as if you were exiting the airbrakes, even if you turn off the engine it continues to cause it to compress

Andre

[nlc]

If you have just connected a 20W bulb, it's normal that you do not have more than 20W ...

To correctly measure the potential of your wind turbine, you would have to connect a large reostat (variable resistor), and on a day of constant wind, charge the wind more and more strongly by measuring the voltage across the reostat, and the current.
So you can draw a power curve that will look like a bell. The top of the bell will be the maximum power point of your wind turbine for that wind speed.

Then the best is an intelligent chopper between the wind turbine and the buffer battery to always charge the wind turbine so that it works at the maximum power point, whatever the wind speed.

[loop]

Hi Cuicui

Yes the blade pitch is adjustable on the ground
Here is a photo of the hub and blade root
The inner nut is welded to the tube
I performed some tests with different timings
A+

[loop]

hi Andrew

the energy captured with a propeller decreases rapidly with the diameter and not linearly

The energy "captured" by a wind turbine is proportional to the area swept by the rotor, therefore depends on the square of the radius

In a propeller you don't just have to look at the speed at the end of the blade, the diameter is directly linked to the power, the pitch directly linked to the wind speed, the width of the blades linked to the torque.

The blade tip speed and the twist directly depend on the lambda coefficient
This coefficient decreases with the number of blades and it is important to know it to determine at what wind speed the wind turbine will reach its nominal speed of rotation, or at least its speed at the start of production (in my case it is 13V)
But it is not enough to aim for a high lambda during calculations ... to obtain it.
This is the difficulty, and between empty performance (before 13V) and under load, it is even more complicated.
To draw the blade I used a spreadsheet available on a very useful site. Link below:

http://voiletech.free.fr/Eolienne/Calcu ... 20pale.xls

An airplane with a large propeller, when you reduce it in descent, it is as if you were exiting the airbrakes, even if you turn off the engine it continues to cause it to compress

Right, on the super Dimona (finesse 25) I can land without speedbrakes when the engine is running
The ground idle speed is at 600rpm and in flight, it cannot go below 800rpm

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