Welcome to the website of Denis Croombs

Wind turbine

  • This turbine is based on a Hugh Piggott's design and is like http://www.robertwebster.org/wind_turbine1.htm
  • Is rated at approx 1.5kwh 24v
  • Has 3 wooden blades
  • Has 10 Coils and produces energy in 5 phases. (I have the moulds and 2 stators already moulded in epoxy)
  • Can be stalled in very high winds by shorting out the coil outputs before the coils are connected to the bridge rectifiers.
  • 12 Magnets. (I have a second spare set of magnets)
  • Has a tail that “furls” in high winds to allow the blades to be turned out of the wind to control the turbine speed, and avoid the turbine destroying itself (hopefully)
  • Most small turbines produce an average of between 8% and 10% of the rated output across the year, so 1kwh (max) x 24hours x 365 days = max of 8760 kwh max per year.
  • Minimum average of 8% should be 700.8kwh/year = 1.92kwh/day
  • Maximum average of 10% should be 876.0kwh/year = 2.4kwh/day
  • I have the 60cm x 80cm isolator control box to allow me to mount the bridge rectifiers and the 200a main isolator switch at the bottom of the turbine pole.
  • I have also purchased 80mt of 35mm 3 phase copper cable to allow me to connect the turbine to the control system in the boiler house.

Turbine tower

Based on a 9.6mt street lamp post.

4 Guy wires to hold it in position.

 

If you want more info on DIY wind turbines see these links:-

http://www.otherpower.com/

 Be sure to read their article The Bottom Line About Wind Turbines before purchasing a wind turbine! It'll inform you on what to expect for power output depending on the machine's size. There are (unfortunately) many scams out there involving small wind turbines (especially the 'rooftop' variety), and this article has a good section by wind power expert Paul Gipe on detecting and avoiding wind turbine scams.

The bottom line is that most small turbines produce on average approx 8% to 10% of the rated output per year, and until power companies pay a reasistic kWh rate for the excess electrical power generated over that used by the person generating the energy.

The main reason why the power generated is low compared to the rated output is the low height of most small turbines, at the height of most large turbines the wind is more consistent and faster.

To get a good idea on the possible energy generated by a turbine please see:-

Wind speed (mph)  2      4       6       8      10      12      14      16      18      20      22      24      26  

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4'     12.56          .18     1.4    4.6    11     22     38      60       90      128    176    234    304    386

6'     28.26          .39     3.1    10     25     49     85      136     202    288    396    526    684    868

8'     50.24          .70     5.5    19     45     88     151    241     359    512    703    934    1215  1542

10'   78.5            1.1     8.6    29     70     137   237    377     564    800    1099  1460  1900  2410

12'   113             1.6     12     42     101   198   341    524     809    1152  1582  2102  2735  3469

14'   154             2.2     17     57     137   270   465    739     1103  1571  2156  2864  3727  4728

16'   201             2.8     22     74     179   352   607    965     1439  2050  2814  3739  4864  6171

18'   254             3.6     28     94     226   444   767    1219   1819  2591  3556  4724  6146  7798

20'   314         4.4     35     116   279   533   948    1507   2248  3203  4396  5840  7599  9640

 

The best way to get more energy is a larger turbine or mount the existing turbine higher.

Towers

We've gone over two very important things that we often think about here at Otherpower. The power in the wind is related to the *square* of the blade diameter (double diameter and you get 4 times the power) and the *cube* of the wind speed (doulbe the wind speed and you get 8 times the power). You have a great deal of control over blade diameter -- you can choose what size machine you buy. What about the wind speed? It's often suggested that the most economical choice is to put up lots of machines on short towers, or mount your wind turbine(s) to the roof. Manufacturers say this stuff because it sells machines -- people do not like the idea that a tower costs money, and they love to hear that once they buy the wind turbine very little further cost/effort is required. However, the wind is your fuel and wind turbines need good clean non-turbulent fuel -- and unfortunately you don't find that on the ground or on your roof!
It is usually suggested by most reputable installers and manufacturers that the most cost-effective arrangement will be to get your wind turbine 30 feet above anything withing 300 feet. If you have turbulant 10 mph winds at 30 feet up and smooth 13 mph winds at 70 feet up then it makes sense to go a bit higher, get out of the turbulance and get into a slightly higher windspeed where you might have *twice* the energy available! This is not the sort of talk that sells wind turbines, but it is reality. In most good installations the cost of the tower is much greater than the cost of the machine itself and there is a good reason for that.