Vernier KW-BWX, KW-BWXC User Manual

Page 1

Basic Wind Experiment Kit

(Order Code KW-BWX, KW-BWXC)

The Basic Wind Experiment Kit is a great introduction to wind energy science and engineering concepts. This is a robust, experimentally rich turbine kit that is appropriate for elementary, middle, and high school students.

Experimentally Rich

 Test electricity production and weightlifting  Explore torque and energy transfers  Measure electrical and mechanical power  Experiment with wind turbine blade design

Renewable

 3ODVWLFSDUWVPDGHIURPUHF\FOHGSODVWLF



What’s Included

Basic Wind Experiment Kit

 Wind Turbine Generator with Wires

(1)

 Nacelle Body Half (2)  Motor Mount Pack (1)  8″ Hex Shaft with Hub Quick Connect

(1)

 Wind Turbine Hub (1)  Power Output Board (1)  Tower Base Leg (3)  Tower Base Locking Ring (1)  Tower Base Hub (1)  Plastic Weightlifter Bucket (1)  Blade Pitch Protractor (1)  Hex Lock (3)  Spool (1)  8-tooth Gear (1)  32-tooth Gear (1)  20″ Plastic Tower (1)  1/2″ Washer (25)  Dowels

(25)

 Power Output Pack

(1)

(Continued on next page)

Classroom Pack

 Wind Turbine Generator with Wires (3)  Nacelle Body Half (6)  Motor Mount Pack (3)  8″ Hex Shaft with Hub Quick Connect

(3)

 Wind Turbine Hub (8)  Power Output Board (1)  Tower Base Leg (9)  Tower Base Locking Ring (3)  Tower Base Hub (3)  Plastic Weightlifter Bucket (3)  Blade Pitch Protractor (3)  Hex Lock (9)  Spool (3)  8-tooth Gear (3)  32-tooth Gear (3)  20″ Plastic Tower (3)  1/2″ Washer (75)  Dowels

(150)

 Power Output Pack

(3)

 3″  12″  3/32″ Balsa Wood Sheet

(25)

This part is a consumable and is excluded from the warranty.

 3″  12″  3/32″ Balsa Wood Sheet*

(5)

 3″  12″ Chipboard Blade Sheet

(10)

 4′ String

(4)

 3″  12″ Chipboard Blade Sheet

(50)

 4′ String

(4)

 8 1/2″  11″ Chipboard Sheet

(25)

NOTE: Vernier products are designed for educational use. Our products are not designed nor recommended for any industrial, medical, or commercial process such as life support, patient diagnosis, control of a manufacturing process, or industrial testing of any kind.

Construction

See construction video online

For help with assembling the nacelle, tower, and base, watch a short video at www.vernier.com/kw-bwx

KidWind Tower Assembly

The turbine tower is made of six pieces:  1 Plastic tow

 1 Ce

nter hub

 1 Locking disk  3 Legs

1. Lock one leg onto the center hub.

2. Attach the two other legs in the same way.

3. Slide the locking disc onto the tower a few inches from the bottom end. Note: If it is a tight fit, lightly sand the tower.

4. With the teeth of the locking disc pointing down, insert the tower into the center hub.

5. Slide the locking disc down the tower and into the hub, locking the tower in place.

To disassemble the legs, use one of your ¼" dowels as a lever. Insert it into the gap on the leg below the hub, and push it away. The leg will pop off.

Building the Nacelle

1. Fit the two identical molded nacelle parts together. Each side has three small holes. Secure the two sides together by screwing six small screws into these holes.

Page 2

2. Fit the nacelle onto the plastic tower and secure it with an additional two screws.

3. Thread hex nuts about 2/3 of the way up the 4" bolts. Next, slide the two motor mount sections up the bolts such that the two concave sections are facing each other. Then thread another hex nut onto each bolt under the mounts. Do not tighten the motor mount sections together.

4. Slide the motor mount assembly into the cutouts by angling them in from the side. See the illustrations below.

5. Once both bolts are in place on the nacelle, thread the wing nuts onto the bottom of each bolt and tighten. Be careful not to over-tighten the wing nuts on the bottom of the nacelle, or you will bend the nacelle. Over tightening may not break anything, but can make your turbine less efficient.

The wing nuts and hex nuts may be used interchangeably in constructing the motor mount. While wing nuts are easier to adjust, the smaller size of the hex nuts allows for more vertical range.

Generator and Gears

1. Place the Wind Turbine Generator in the motor mount, with the wires close to the tower. Then tighten the nuts to hold the generator securely in place. Attach the wires to the

plastic tower wit

h zip-ties or tape.

Opti

onal: If you are using a PVC tower, you can snake the

wires from the motor through the slot in the nacelle behind the motor mount. Then the wires can go down through the PVC pipe. On a wood tower, the wires can go out the side of the nacelle.

2. Attach the smallest gear (pinion) to the drive shaft of the

generator. The small hole in this gear should slide onto the generator drive shaft and the pinion will be held on by friction.

3. Slide the hex shaft with attached Hub Quick Connect into the hole at the top of the nacelle. You may need to wiggle or rotate the hex shaft as you push it in. Slip a hex lock onto the hex shaft with the collar facing the nacelle.

4. Attach the 32-tooth gear onto the hex lock. Move the generator up or down so that the pinion gear meshes with the gear on the hex shaft.

Add Turbine Blades

Assemble blades by gluing dowels onto blade materials cut into shape if desired. You can also shape the blades after assembly. We recommend hot glue for quick assembly, but classroom white glue or wood glue will also work if you have time to allow for drying.

Loosen the Wind Turbine Hub and insert blades symmetrically around the hub. Before the blades are held tightly, angle the blades as desired. Tighten the hub to lock the blades in place.

The Hub Quick Connect (HQC) allows for easy removal and attachment of the hub. This enables users in busy classroom environments to change blade configurations quickly and easily. If you wish to secure the Wind Turbine Hub onto the HQC, use the set screw provided.

Strong wind, large or out of balance turbine blades, and wear can make the HQC unstable.

Caution: The hub is designed to have a very tight fit to the Quick Connect, but if your blades are unbalanced or your turbine is not directly facing the wind, it may come loose. Be careful with blades that are out of balance.

Measuring Turbine Output

Your turbine is converting wind energy to electrical energy, in some amount. There are several ways to get an idea of how much energy the turbine is generating.

LED

Connect the positive terminal wire of the generator to the longer lead of the LED and connect the negative terminal wire to the shorter lead of the LED. The brightness of the LED is a general indicator of how much energy is being generated.

KidWind Power Output Board

Connect the positive and negative terminal wires of the generator to the visual voltmeter terminals on the KidWind Power Output Board (KW-POBD) using alligator clip leads. Reverse the wires if the “reverse polarity” LED lights. The visual voltmeter lights an additional LED for each additional half-volt of electric potential. The energy being produced is proportional to the voltage.

Vernier Energy Sensor

Connect the positive terminal wire of the generator to the red terminal of the Vernier Energy Sensor (VES-BTA) and connect the negative terminal wire to the black terminal of the Energy Sensor. Connect a load such as a resistor or the Vernier Variable Load (VES-VL) to the Load terminals of the Energy Sensor. Connect the Energy Sensor to an interface and use either LabQuest or Logger Pro to see readings of current, voltage, power, and resistance. Energy is the product of power and time if power is constant, so you can use the power reading as an indication of electrical energy production.

Page 3

Multimeter

Connect the positive terminal wire of the generator to the red wire of the multimeter and connect the negative terminal wire to the black wire of the multimeter. Set the multimeter to measure DC voltage at the lowest setting. The number shown on the multimeter is the amount of electrical potential, measured in volts, that the turbine generates. The energy being produced is proportional to the voltage. If there is no reading, shift the setting to the next higher voltage setting. Keep doing this, as needed, until you get a voltage reading.

Determine Polarity To determine the proper polarity of the turbine, connect it to a voltage probe, Vernier

Energy Sensor, KidWind Power Output Board, or a multimeter. If the voltage reading is positive, the lead connected to the red voltage probe wire, red Energy Sensor terminal or red multimeter wire comes from the positive terminal. If the voltage reading is negative, the lead connected to the red voltage probe wire, red Energy Sensor terminal, or red multimeter wire comes from the negative terminal.

When using the Power Output Board, a small LED marked “reverse polarity" will light if the wires are connected with the positive generator wire attached to the negative terminal and the negative generator wire hooked up to the positive terminal.

It is a good idea to mark the wires with tape so you know which is positive and which is negative.

 How much electricity do various devices require?  LEDs require at least 1.6 volts to light. Polarity is important with LEDs, so if it is

not working, try reversing the LED connections.

 Small DC motors need 0.6–0.8 volts.

Lifting weight with wind energy

Lifting weights with the wind turbine is another great way to explore wind energy. Convert the Basic Wind Experiment Kit to a weightlifting turbine.

1. Tie the string to the spool, taping it down so it does not slide. Add one hex lock to each end of the spool, pressing them into the spindle hole.

2. Affix the plastic bucket to the other end of the string, using the holes pre-drilled in the bucket.

3. Remove the 32-tooth gear from the hex shaft. Push the spool onto the hex shaft.

 See construction video online

For help with assembly, watch a short video at www.vernier.com/kw-bwx

Experiment Ideas

Your Basic Wind Experiment Kit allows you to perform many different experiments with wind energy. Here are two ideas to get you started:

Experiment with the blade pitch

When the blades are flat against the wind (0°), the air will push the blades in the same direction as the wind. This results in a minimum transfer of energy from the moving air. When the blades are at 90°, there is no push at all from the moving air,

since the wind flows past the blades instead of pushing on their surface. Between these two extremes, some of the force pushes each blade sideways while some force pushes them backwards.

Experimentally determine what pitch angle lights the LED the brightest or generates the most energy, or lifts the most weight. Use the same wind speed for the entire experiment.

Experiment with the number of blades

For this experiment it is very important to keep the pitch of the blades constant. It can be easier to start with one or two blades and then increase and record power output as more blades are added.

When testing the number of blades on the weightlifter, one strategy is to keep the weight constant while altering the blade number. Then measure the time it takes to lift the weight to determine which blade setup produces the most power. The faster it lifts the weights the more power generated.

Troubleshooting

The turbine does not spin when I put my turbine in front of the fan

Make sure all the blades have their pitch oriented in the same direction and are not “flat” to the wind. Make sure the blades are not in contact with something that is preventing them from moving.

The turbine slows down when I attach it to a load (resistor, pump, bulb, motor, etc.)

This is expected. Electrical loads all have some resistance. Resistance makes it harder to push electrons through the circuit, which means it is harder for the generator to turn.

The voltage readings keep changing

Some fluctuation is normal. Here are some things you can work on to reduce the variability of the voltage measurement:  Make sure the blades are not changing shape as they spin. You may need to use a

stiffer blade material.

 The wind produced by the fan may be fluctuating.  Your blades may be unbalanced, unevenly distributed, or producing unequal

amounts of drag.

The readings on my multimeter are negative

The meter is reading the polarity of the wires. As your turbine spins in one direction one wire will be the positive lead and the other wire will be the negative lead. If you spin your turbine the other direction the polarity of the wires will be reversed. For LEDs and Fuel Cells hooking up the correct polarity matters—on other items the polarity is not critical.

If you prefer not to have negative values, reverse the wires relative to your measuring device.

Based on the power in the wind equation, longer blades should generate more power but mine generate less power.

The blades on your turbine may be bigger than the diameter of the fan. If that is the case, the extra length is only adding drag so the blades will slow down. Additionally,

Page 4

poor design can make longer blades have significant drag. Keep experimenting to determine the ideal blade length, shape, and pitch.

Additional Resources

For more information about wind energy, see KidWind’s document, Learn Wind, available at

http://learn.kidwind.org/sites/default/files/learn_wind.pdf

Warranty

This kit contains many parts. The Generator is warranted to be free from defects in materials and workmanship for a period one year from the date of shipment to the customer. Other parts in the kit, excluding consumables, are warranted for a period of five years. Consumables are clearly marked on Page 1 and 2 of the user manual.

Vernier KW-BWX, KW-BWXC User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual