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Wind turbine was bolted to a trailer and rpm, voltage and tsr was measured by connecting the generator to a very high power multi-tap resistor. The turbine was allowed to speed up to an open circuit voltage of 65 V (666 rpm) before the resistor load was connected. The measurement method and results are presented.

R_{s} is the resistance of the generator windings plus the power cable; 5.75 ohms

R_{l} is the resistance of the load; 6.6, 10, 15, 21.5 and 25 ohms

Power generated by the blades was calculated by dividing measured power by the efficiency of the generator. Once the blades have been characterized, a new generator will be designed.

Power generated by the blades is calculated by the following method:

Voltage across the resistor load (V_{l}) was measured,

V_{s} = V_{l} x [(R_{s} + R_{l}) / R_{l} ]

Power produced by blades and lost in generator, power cable and resistor load is given by;

P = V^{2}/R

P = V_{s}^{2} / (R_{s}+R_{l})

The results from the wind turbine test

are included below.

are included below.

30 km/h

40 km/h

45 km/h

50 km/h

40 km/h

45 km/h

50 km/h

Rotational Speed (rpm)

30 km/h

40 km/h

45 km/h

50 km/h

40 km/h

45 km/h

50 km/h

Power (Watts)

30 km/h

40 km/h

45 km/h

50 km/h

40 km/h

45 km/h

50 km/h

Balsa, glue, tin sheet $10

Gel coat $40

Plastic sheet, plaster $25

Modelling clay $23

Vinyl ester resin $110

Fibreglass cloth/mat $80

Frequently asked questions about plan orders, blade design, electrical work and generator matching can be found on our Q&A pages.

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Power (Watts) vs Speed (km/h)

25Ω

756

1040

1299

1425

756

1040

1299

1425

21.5Ω

844

1143

844

1143

15Ω

922

922

25Ω

177

335

521

628

177

335

521

628

21.5Ω

249

457

249

457

15Ω

452

452

25Ω

6.6

6.8

7.5

7.4

6.6

6.8

7.5

7.4

21.5Ω

5.5

6.0

5.5

6.0

15Ω

5.2

5.2

Tip Speed Ratio (TSR)