Eoltec Scirocco (Weole) Wind Turbine

The French company Eoltec developed a 6 kW wind turbine in the early 2000’s that was quite unique for its time. For many years we were the distributor of these turbines for North America. Eoltec went bankrupt in 2013, unfortunately leaving many Scirocco owners high-and-dry. We collected a number of documents over the years that could still be of use to those wind turbine owners. They can be found in this article.

The Scirocco wind turbine had a number of unique features that were not commonly found on a small wind turbine. It had pitch control, that limited the RPM in high wind to a safe 245 RPM, by repitching the blades to stall-angle. It did not need a dump-load or other mechanism to keep it under control in high winds or without a load, pitch control would take care of that. The Scirocco was a 2-bladed turbine, also unusual in a world with almost exclusively 3-bladed ones. Its blades were very carefully designed and made, with a complex airfoil curve that made them very efficient for their size. Its low-RPM and efficient blades made it very quiet too. It had a large permanent-magnet alternator that hooked up to a grid-tie inverter (initially a Magnetek, later a Power-One inverter).

Eoltec was bought by another French company, named Weole. When Weole went bankrupt they took Eoltec and the Scirocco wind turbine with them. The timing was bad, as at that point it had become a pretty good turbine, with all the bugs worked out.

If you happen to run into a Scirocco and need a tower for it, there are a number of conditions that tower needs to comply with for it to work in a way that does not result in an Undesired Outcome™. First and foremost, the tower needs to handle the tower-top weight of 202 kg (450 lbs), an easy one for any tower, and the thrust-load that the wind exerts on it at a 60 m/s wind speed (135 mph) of 5800 Newton (1300 lbs). That last one requires a pretty beefy tower.

Besides these forces, the resonance frequency of the tower plus turbine matters as well. This is only an issue for towers that do not have guy wires (for guyed towers it’s easy enough to change the resonance frequency by tightening or loosening the guy wires a little). Resonance frequency matters, because if the tower’s frequency happens to overlap with the frequencies (vibrations) of the turbine it will likely results in the destruction of the wind turbine, tower, or both. The tower frequency (mode) requirements are as follows:

• First natural mode of the tower and turbine assembly ≤ 1.5 Hz
• Second natural mode of the tower and turbine assembly ≥ 6.8 Hz

An engineer can calculate the tower modes for self-support lattice and monopoles towers.

In general we suggest guyed tilt-up towers for any wind turbine, if at all possible. They are economical, and moreover, they allow you to lower the turbine for maintenance and repairs. For someone who is mechanically inclined it is entirely possible to do their own turbine maintenance. It is a very different proposition to do this 100′ in the air vs. on the ground though, and paying for a wind turbine installer to come out and climb a tower every time there is work gets expensive really quickly.

Back in 2006 we took a Scirocco wind turbine to the Woodstock Farm Show. There was lots of interest! It would be a waste to let the story and pictures disappear, so here it is…

Solacity was invited by Green Breeze Inc. to share their stand at the 2006 Woodstock Farm Show. Farmers in Ontario are putting up wind turbines in large numbers these days, and with the Standard Offer Program this will be even more the case. Green Breeze Inc. is a company that installs the larger wind turbines, currently 30 kW and up, and many of their customers are farmers.

We took the opportunity to bring a Scirocco wind turbine and put it up for display. Below are some pictures that show the process of installing a Scirocco, and the construction details of the turbine. What should be clear from the pictures is just how solid this machine is. You can click on the pictures below to see a larger image.

The Scirocco comes in two boxes, one for the blades and tail boom, and another one with the nacelle, alternator, and nose cone. Everything comes nicely wrapped, and packed to survive the trip from France.

The box with the blades can be carried around by two people, the alternator box however is too heavy, and takes more manpower to handle. Luckily we had help from Gerry Wheeler, who is a wind turbine installer in daily life, and Wilco Vercoelen, the owner of Dommel Valley Green Power.

Gerry had constructed a pole with the proper flange to mount the Scirocco onto. The first step was to take the nacelle and bolt it down on the pole. The nacelle contains a big bearing that allows it to turn around the mounting pole.

The next picture shows a close-up of the inside of the nacelle. You can see the slip-ring assembly that allows the turbine to spin around the tower as the wind changes direction, without winding up the power cord to the turbine.

With the nacelle mounted  we figured it would be better to first get the tail-boom bolted on, before installing the alternator. The alternator is by far the heaviest part of the turbine, and with the mounting pole only a few feet into the ground we wanted to keep it more or less balanced. The picture shows Wilco holding the tail-boom while the bolts are being installed.

We could no longer postpone the difficult part, installing the alternator. A 6.5 kW permanent magnet alternator is very large, and very, very heavy! Two people can barely lift it up. What is worse, it’s round and does not have anything to easily hold on to. How we wished Eoltec had installed a few handles to make this easier…

The wires coming out of the alternator are surprisingly thin, despite the need to move 6.5 kW through them. That’s over 8 horsepower! This is thanks to the high alternator voltage of 240 Volt. The same also helps keeping the wiring size (and cost!) down when it comes to connecting the wind turbine to the inverter.

The pole did not topple over, and with somewhat bruised fingers (from getting caught under the alternator as we tried to lift it from the box) it got bolted on.

Since this was not going to be a working turbine we did not bother to hook up any of the wires. For a real install you would reverse the order, and install the alternator before the tail boom, so there is access to the slip-ring assembly to connect the wires.

On to the heart and soul of this turbine: The propeller hub and pitch control mechanism. The Scirocco contains what is in essence an old-fashioned governor, just like those found on a steam engine.

Two weights are flung outward as the propeller turns, which causes the propeller blades to change pitch. At the same time this pushes in a strong spring that is mounted in the hub (the green object in the picture). The effect of it all is that propeller RPM is limited to 245 at any time, with or without an electrical load on the alternator.

The yellow object behind the hub is the back part of the nose cone. We wanted people to be able to see how the Scirocco does its job, and did not mount the round front part of the nose cone. You can see it sitting in the box in the first picture.

Time to move on to the blades. The blades are hollow, and in fact the picture shows a view of the inside of a blade. Each blade has an aluminum root insert, which is what bolts onto a large bearing, which in turn bolts onto the propeller hub. The bearing allows the blade to rotate, causing its pitch to change, to control the propeller RPM.

The governor weight gets mounted between the blade root and bearing. The pin, with a bearing on top, that is shown sticking out in the picture is what grabs into a corresponding notch inside the hub. As this pin turns, it pushes in the green spring inside the hub.

The second blade gets the same treatment, and that concludes the installation.

Gerry has installed many wind turbines, large and small. He commented on how well the Scirocco parts fit together, and the quality of construction of them. He has seen different on many occasions, and on much more expensive turbines!

All told, it took us a little bit over an hour to put together the Scirocco. Eoltec did an excellent job in making this virtually foolproof; Parts will for the most part only fit together in a certain way. In case of questions the drawings in the installation manual helped out to clear things up.

It was not particularly difficult to install this wind turbine. However, some parts are heavy (The alternator in particular), making this a two-man job. In fact, having a third person around came in handy many times, and is recommended if you want to try this at home.

The final pictures were taken during the Farm Show, at one of the few quiet moments. Despite the bad weather this show was very busy. Farmers are clearly not intimidated by a little rain! From morning to evening people were asking questions about the Scirocco, and we handed out over a thousand information flyers.

There were a few other wind turbines at the Farm Show, but the Scirocco was the best looking of them all!