Design, construction and testing of a 1.4 meter diameter, 3 blade wind turbine. 500 Watt Kevlar turbine blades.

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.

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 = V²/R

P = V_s² / (R_s+R_l)