Overview and Background

Made for students by teacher and engineers for the Kidwind as a teaching tool!

The design focused on an active learning approach. How does a generator work? let's learn by doing!

The geared generator variation.

The video describes the basic technique of building the generator from the 3D printed parts.

Lesson Plan and Activity

From Kid wind lessons - Windwise 9 lesson " How does a generator work?"

The Kidwind website lists the lessons on wind power education. This generator was designed for Windwise lesson 9 "how do generators work."

Testing Kidwind Whitebox designed blades on the desktop.
Performance of the blade designs can be done with simple equipment. This equipment is:
Standard Kidwind tower and gears
Multimeter or Vernier data device
Load resisters 100 Ohms and 30 Ohms (internal to the Vernier device.
Some alligator test leads.
Optional – Anemometer
Tachometer
A box fan or other stable wind source of 4 m/s to 5 m/s.
Blade set for each team.
Angle measuring device.

The testing objective depends on the curriculum, lesson or lead up activity.
Some possible inquiry could be:
Which blade set is better designed for this wind speed?
What is the optimum attack angle for the blade set?
Comparing designs – which blade set comes closest to the designed Whitebox Output data?
What gearing produces the most power for a given blade set?

Equipment Setup
Baffle and raise the fan
Center of the blades up and down and back and forth on the fan.
Tape the tower down at a fixed distance from the fan. 24” is a good distance.
Set up the Standard Kidwind tower with 8 to 1 gearing.
Discuss safety in working with spinning blades and electrical devices.

Notes:
Select 3 angles of attack – usually 5, 10, and 15 degrees works. This all depends on the blade design. The sample NACA 318 blade files work but the Somer blade files requires greater angles of attack.
On some blades it is difficult to find which side of the blades should face the wind. Trial and error. Try 15 degrees one way then 15 degrees the other.
Twist the blade by the root section. The blades will break if they are twisted at the tip. Measure the blade angle at the tip.
Start testing at no load. Let the turbine come back up to no load speed before applying the next load.
Setting the angle is simple with the bubble level home made tool. Download the file. It prints in a few hours. A level bubble is readily available on the internet. This one came from Temu. A piece of wood or plastic can serve as the indicator.
Some blades need a slight push to get going before they can become aerodynamic. There is a shift in performance when the achieve the aerodynamic lift. Wait for the maximum volts no load before applying a load.

The sample spreadsheet will have the equations embedded in it.
As a reference:
Power of the wind per blade rotor area: 1/2 1.23 pi r^2velocity^3
Turn speed ratio =( pi(2r/100)*( RPM/60))/windspeed m/s
Power Output Watts = Voltage^2/Resistance
Coefficient of performance = Power in/Power Output

Materials Needed

PLA+

Any filament will work. Part printing time are long, 10 to 13 hours each.

2 skateboard bearings
1' 5/16" steel rod
7 mm hose clips
1 lb of 26 gauge magnetic wire

Skills Learned

troublesooting
electronics
problem solving

Preparation

Preliminary printing

The first time the activity is done -The long print times need to be considered before the actual activities can begin. Mechanical parts need to be purchased.
When all the parts are ready the actual build and test can be done in two class sessions.

Rubric and Assessment

The video reviews the basic tests for any generator.

Generator