1500 W wind problem 24VDC

[Ruthenian]

First result:
- Vacuum alternator, measure on a coil
20 Hz gives 12 V AC
40 Hz gives 24 V AC
130 Hz gives 83 VAC

-Alternator supported on 12 V DC battery.

Hard hard, my drill 500 W smoked. The couple seems to me huge.
The maximum I read 5 A for a frequency of about 40 Hz. To confirm tomorrow. Because I struggled to hold and the alternator, the drill and cable measures.

[loop]

Bonjour,

20HZ for an alternator to 7 pairs of poles that gives us a rotation speed of 20 / 7 x 60 = 170 rpm
The rectified voltage must then be:
12 x 1.414 = 17 V,
An 12V battery would rather begin to charge at a voltage of the order of 10V AC, therefore still at a lower speed, approximately 140 rpm.
This is rather a good sign for a wind turbine alternator but the power curve looks very "steep" for the rotor which is too braked as soon as the current appears.
The manufacturer has thought well to multiply the number of blades to increase the torque, but it is a little simplistic because it is necessary to be able to maintain this mini speed to produce.
A test with MPPT would be talking, I think.

A+

[Ruthenian]

Hello,

The MPPT test requires the purchase of new equipment which is not cheap. Especially in the end, I don't want to use a battery. So a "useless" investment. Unless the mppt charger can be connected directly to the inverter. The cohabitation between the two risks being olé olé.
And that does not solve my huge noise of junk spread by the mat, probably due to cogging.

I have two inverters mppt, with both the result is the same. As you explain, the speed of the blades is not maintained and it slowed down.

You must be probably right.

I will think about it and continue the tests.

[loop]

If the network converters have the function mppt and that does not let the rotor accelerate with the voltage, then it is that the problem comes from the exploitable power of the propeller.
It is possible that the pitch of the blades is not adapted.
The electromagnetic brake generated by the appearance of the current in the coils decreases the TSR (wind speed / tip speed ratio).
The rotor accelerates well empty but picks up when asked for torque. The stall usually results in a buzzing of the propeller.

For vibrations by cogging, it should be known that they occur at all speeds. When you rotate the alternator slowly by hand, you feel like notches (as there are notches in the carcass of the stator).
On one of the videos I had the impression that the vibrations appeared suddenly, maybe just when the torque absorbed by the alternator increases.

A+

[dedeleco]

The vibrations in amplitude are a function of the play in the bearings and can amplify over a certain speed, with the bearing that amplifies this game, or even destroy the bearings in the long run.
I'm not sure that the propeller is balanced. To check. In this case the noise increases quickly with the speed.
The mat can come into resonance if no luck !!
The stall, a horrible plane disaster, is a function of the angle of incidence of the blades, which must be adapted to the wind, the speed and the power required.
The turbulence of the wind causes stalls much more than a regular wind (well known in windsurfing and which prevents up the mistral near the coast)

To test separate elements, propeller with brake separated from the alternator, as unsuitable between them, in first impression!

The theory is good in practice for the induction (relatively simple) and very complex for the flow on the helix (calculations on computers which are valid) and the complex chaotic vibrations with resonances and chaos.
If I saw in operation, some tests allow to know the cause of the vibrations, but long in writing, because of the results of the tests and it requires a complete course of vibration mechanics to assimilate well.
See the vibrations by turning without wind with drill.

The mppt must be adapted to the operating range of the alternator (voltage, current, regulation, etc.) and therefore will not solve anything.
Currently without accurate information, so in the dark, it can not work, alternator with not enough magnets for speed and power.

[Ruthenian]

To test separate elements, propeller with brake separated from the alternator, as unsuitable between them, in first impression!

How to do ?

Imbalance of the weight? Center of inertia of the blades ...?

For vibrations, you understood correctly, it is at start-up and at "stopping". The one afterwards, purring, I consider them normal.
The starting or stopping noise is interrupted later.

The propellers on the other hand whistle a lot as soon as the rotation picks up speed. We hear them at more than 50 meters (in the direction of the wind)

The forces are so great that the rudder oscillates during the stop and makes me over-jump the weather station.

What more precise information can I communicate to you knowing that I have only the means of the edge to carry out the tests.

Here is a small video if it can advance:
Thank you for not paying attention to this test bench !!


http://www.youtube.com/watch?v=6B66lZ_TGhc

[dirk pitt]

reading this post from the start, it all actually looks like an alternator with a power curve that is too "steep" compared to the associated rotor.
result, the advertised power is that of the alternator but can not be provided by the rotor.
the only solution in my opinion is to put after the three-phase rectifier a chopper that will limit the current to fall back into powers compatible with the rotor.
without going to the MPPT, a simple drive for a DC motor can be used and a max.
a simple electric scooter dimmer will do the trick.
certainly, we can not extract the maximum power if the max current is fixed but it will be better than currently.
by improving, one could enslave the value of the potar of the variator to the speed of the wind to vary the max.

[Ruthenian]

Hello,

Excuse me but I do not see the point of using an additional chopper knowing that I have a MPPT inverter that is supposed to adapt its power output according to the power available at the source.

[Gaston]

Hello,

Excuse me but I do not see the point of using an additional chopper knowing that I have a MPPT inverter that is supposed to adapt its power output according to the power available at the source.

The MPPT is designed to get as much power as possible from the generator, but this generator seems oversized compared to the wind turbine.
The chopper, on the contrary, would be sized to restrain the power drawn in order to avoid causing the wind turbine to "stall".

[dirk pitt]

if you have a MPPT, it should actually do the same thing because as soon as the voltage collapses, it should decrease the current to stay at the point of max power.
the problem, I think is that the MPPT are expected in general for photovoltaic sensors whose characteristic voltage / current is very different from your wind turbine.
I'm not sure that, therefore, the MPPT can do its job that would maintain a correct voltage by playing on the current drawn from the alternator.