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.
Measurement of results from the wind turbine
Note: Method of testing turbine generates turbulent wind, affecting efficiency. The results should be used as a guide only.
Rs is the resistance of the generator windings plus the power cable; 5.75 ohms
Rl 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 (Vl) was measured,
Vs = Vl x [(Rs + Rl) / Rl ]
Power produced by blades and lost in generator, power cable and resistor load is given by;
P = V2/R
P = Vs2 / (Rs+Rl)
The results from the wind turbine test
are included below.
Rotational Speed (rpm)
System cost (AUD)
Balsa, glue, tin sheet $10
Gel coat $40
Plastic sheet, plaster $25
Modelling clay $23
Vinyl ester resin $110
Fibreglass cloth/mat $80
Total cost $288
Total cost of the wind turbine
Continue to summaries about.....
Dumpload Charge Controller
Frequently asked questions about plan orders, blade design, electrical work and generator matching can be found on our Q&A pages.
Free plans for 500 W
Testing the wind turbine
Figure 10. Measured Power
Power (Watts) vs Speed (km/h)
Figure 12. Efficiency vs TSR
Figure 11. Measured RPM vs. Wind Speed (km/h)
Tip Speed Ratio (TSR)