Its great to be reading some constructive feedback rather than the unprofessional rubbish posted by "Peterfutur" of FuturEnergy at
http://energistar.com/PHPbb3/viewtopic.php?f=1&t=14&p=20&hilit=futurenergy#p20
To answer some questions.
My prime motivation for purchasing the FE 1048 was to assess its performance with the intention of becoming an Australian Dealer for the product. I made this very clear to the manufacturer at the time of ordering. I was well aware that this turbine did not produce as much power at low wind speed as some other 1kW rated turbines available in Oz, but it was much better value $/W from spec's. The Data Logger that I was looking at to measure the performance has turned out to be less accurate than I require and thus have still not got a logger. Having witnessed the performance out of the box, it quickly became obvious that I don't need a logger to tell me how bad this FE turbine performs. This is why I do not give any specific wind speed or power figures as yet.
I was also well aware that my wind site is not ideal for a HAWT installation, but was the best site on my property. The Winds from NW thru West (predominant) to SW are clear from significant turbulence. It is only the performance of the turbine in wind from this direction that I have considered.
I do not expect any turbine to perform well in any other wind conditions at my site.
So considering ONLY good, strong clear winds:
1. With the standard tail fitted, the turbine will not stay pointed at the wind for long enough to make much power. Although that's pretty much the key point, I will offer some of my ideas and observations as to why this is.:
1a. The tail is quite short, and is mounted at quite an acute angle to the line of the blade axis.
This is to compensate for the offset of the blades to the pole mount as required to allow the furling mechanism to function. Thus the tail seems not to command the direction of the blades as it should.
1b. The small diameter, 5 blade design seems to create quite a "void" behind the blades especially in high winds. Even with my "Long Tail Mod" the tail tends to oscillate back and forth within this void, (see 5. below)
1c. The 5 blade design allows for 10 points of minimum resistance to change of direction. Comparing this; A 1kW two blade HAWT, of say >3m diameter, Has only two positions per rotation where the resistance is a minimum. Just a thought, one would need to do the math.
1d. The standard pitch pins supplied with the turbine set the blade pitch at 25°. This is more suitable for higher wind speeds. (Futurenergy sent me some 28° pitch pins that, may improve the performance in normal winds.) This, coupled with the high start up RPM of the PMG means that in moderate winds, where one would be hoping for at least a small amount of power output, the turbine is not producing any power at all and thus the blades are not loaded. This lack of blade loading means that when the wind drops suddenly, the spinning blades act as a propeller and push turbine in the opposite direction to its furling direction (I hope that makes sense). This sends the assembly into a spin, so even if the wind recovers its velocity quickly, the turbine is not pointing at the wind for to take advantage of it. Points 1a, 1b, 1c above contribute to this problem.
2 . Look at ANY specification for any wind turbine . You will notice that FuturEnergy are one of the few that have shown at what Battery Voltage the reported turbine power is measured at. The FE turbine for example, looks like it produces a little bit of power at low wind speeds. But the battery voltage is 52V. My experience is that at an Absorbtion Voltage of say 57.6V, the turbines Open Circuit voltage is not high enough to pass any current to the batteries at all. This is a whole topic that needs to be explored and manufacturers should be pushed by the consumer to provide power figures at a fixed voltage, representing normal Float, Absorption, and Boost charging modes.
2a. My calculations suggest that he PMG needs more windings, and a subsequent higher internal impedance to start generating earlier. Perhaps achievable by changing to a Star wound stator from the standard Delta connection. BUT this may cause excessive heat to be generated in the PMG in high winds .
3. I'm not worried about Iron Loss.
4. I don't consider Cogging to be a problem. As long as the wind speed required to start the turbine spinning is less than the speed at which the turbine starts generating.
5. THE LONG TAIL MOD.
In an attempt to improve performance by getting the blades pointing at the wind, I extended the length of the tail beam using 25mm aluminium tubing to about 2m total. This was a quick and dirty test and I expect that some improvement can be made by altering the fin angle. Also, this mod prevents furling in high winds, and adds additional weight to the assembly. Further design is needed to finalise this mod.
The photos tell the story. The turbine now stays pointed at the wind and generates quite good power. Although the tail still seems to wander about in the void behind the blades, this mod is vast improvement on the standard tail design.
6. The turbine is generally low in noise output. However it is noisy when the blades are not loaded and the wind speed is dropping (blades are acting as a propeller)
Conclusion.:
If FE were to make some modifications to the tail design, I reckon this turbine would no longer be just a great looking, well manufactured toy, but a value for money product.
That's it from me for now, Ill post the final mods if /when I get around to it.
I've got a bathroom to renovate, and an Internet shop to set up.
Happy Trails.
<BR><img src="http://www.otherpower.com/images/scimages/5828/Long_Tail_2.JPG" width=80%><BR><BR><img src="http://www.otherpower.com/images/scimages/5828/Long_Tail_3.JPG" width=80%><BR><BR><img src="http://www.otherpower.com/images/scimages/5828/Long_tail_looking_South.jpg" width=80%><BR><BR><img src="http://www.otherpower.com/images/scimages/5828/Long_tail_looking_SoutWest.JPG" width=80%><BR><BR><img src="http://www.otherpower.com/images/scimages/5828/Long_tail_looking_to_the_West.JPG" width=80%><BR><BR><img src="http://www.otherpower.com/images/scimages/5828/Solar_Tracker_FE_on_hill.JPG" width=80%><BR><BR><img src="http://www.otherpower.com/images/scimages/5828/Solar_Tracker_2.JPG" width=80%><BR>
