Wooden Generator

Introduction:

An electric generator is a device that converts mechanical energy to electrical energy. In a generator, a moving magnet will push the free electrons in a conductor back and forth. Movements of electrons along a conductor are called electricity. Since in this type of electricity electrons swing back and forth, we also call it alternative electricity and show it with symbol AC. Home electricity is an AC electricity with frequency of about 50 Hertz; In other words, electrons swing back and fort 50 times per second.

In a wooden generator, the main structure is made of wood. The only non wooden parts are the magnet and the wire.

The following images show all the steps of making this generator.

 Kit content: Inspect the parts in your kit to make sure that you have all the parts shown in the picture. Compare the size of the four rectangular pieces. Two of them are about 1/6" smaller. Start making a wooden box as described below:

Are your materials different from the above picture? CLICK HERE for the instructions of the new smaller version of wooden generator.

 STEP 1: Use one large square balsa wood and one large rectangle. Apply some wood glue to the bottom side of one of the rectangles and attach it to one side of the large square.
 STEP 2: Now, take one of the smaller rectangles and apply some wood glue to bottom, left, and right sides of the rectangle. Now, properly place it on the square as shown on the image to the right. This piece should glue to the large square and the previous rectangle when done correctly.
 STEP 3: Next, take a third rectangle which should be one of the larger rectangles and glue the bottom, right, and left sides of this rectangle. Place it on the square so it is parallel to the other large rectangle that you attached in the first step.
 STEP 4: Apply some glue to the bottom, left, and right side of the last rectangle and complete your box. Make final adjustments while your box is on a flat surface.
 Temporarily place the other large square on the top and place a weight on it. A small cup can be used as a weight. Do one more final adjustment if needed. Make sure that the temporary large square will not stick to the rest of the box at this time. Wait about two hours for the glue to dry. (Prevent excess glue, or place a piece of 4" x 4" paper between the box and temporary large square)
 STEP 5: Insert the magnet in the hole of the wooden dowel as shown in the picture to the right. Center it and use some glue to secure it. When inserting the magnet, hold the thick part of the wooden dowel to protect it from breaking. The magnet and wooden dowel together will form the rotor for your electric generator.
 STEP 6: Insert your wooden dowel into the hole at the center of the square box that you have constructed. At this time the magnet should be inside the box.
 STEP 7: To complete the box, place the other large square on top of the other square so that the wooden dowel extends out of the hole at the top of the square. So that the square will be permanently attached to the box, apply some glue to the edges of the square and wait for the glue to dry. You now have a box with a magnet that can turn both clock and counter clockwise when the extended part of the wooden dowel is spun.
 The final box should look similar to the picture to the right.
 STEP 8: The stator is about 300 loops of continuous insulated wire that you wrap around the box, close to the center.
 Leave about one foot of the magnet wire and then proceed to wrap the magnet wire around the box. Be sure to begin wrapping at least 1 foot in from the beginning of the wire or else you will run into a problem later on. Wrap the wire loosely so that the box will not be crushed. Be sure to wrap the wire at least 200* time or more. 300 turns is the average. More wire in the coil results in more electricity and a more powerful generator.  When the magnet wire is finished, leave another one foot wire unwrapped at the other end just as you did in the beginning of the wire.

* With 200 turns of wire the amount of electricity is too low to light up any light. If you want to get light, use all the wire that comes in your kit.

Twist the two ends of the wire so the wire does not unwind. You may also use some masking tape to keep the wires in place. Note that the wire has an invisible insulation, so coppers are not touching each other when you wrap them or twist them over each other.

 STEP 9: Remove about one inch of insulation off the two ends of the wire coil. Insulation can be removed using a sand paper or any other sharp object. Bare copper wire has a distinct metallic color that will be observed after you remove the insulation.
 Connect the two ends to the two screws of the bulb holder. To do this you must first loosen the screws, place the bare wire under the screws, and then tighten the screws.  Screw the light bulb on the base.This generator worked perfect. I got the light just by turning the dowel by my fingers (fast).
 In this model I am using a 1.2 volts light bulb. I have 150 loops of wire in either side of the dowel. That is all the wire (250 feet) that comes in the kit.  TEST YOUR WOODEN GENERATOR! You are finally done with your wooden generator. The final product should look somewhat like the image to the right. To test your wooden generator, spin the axis (wooden dowel) quickly to see the light.
 If you are not able to spin the wooden dowel fast enough, you will probably get no light or a flicker of light that is too dim to even see. You can try spinning it faster by using an electric drill, however, doing this might spin it so fast that your light bulb may possibly burn.
 You can get small amounts of light just by turning the axis of your generator by hand. However an adult may also try to spin the axis using another motor such as a drill.
 Another method for turning the rotor is using bow (an arc and a cotton string). Simply connect a few pieces of wood to make an arc like structure. Connect two ends of the arc using a cotton string. This string must be fully stretched when it goes around the wooden dowel.
 Place the end of the wooden dowel on the string and twist it such that the string turns around the wood dowel (axis of your generator). Hold the motor by one hand and the arc in the other hand. By pushing the arc back and forth, you should be able to spin the axis fast enough for the light to come up.
 I think any wooden stick can be used for this purpose and it does not have to be in the form of an arc. Try it! Historically this method has been used to run some kinds of hand drills. Craft men have used arc strings to make holes on wood, metal and ceramic pieces.

 Connecting LED (using Heat Shrink Tubing)LEDs light up easier than incandescent light bulbs. To connect the LED you must sand the ends of the wire in order to remove the insulation and then connect each end of the wire to one of the pins of the LED. Use an electrical insulating tape to hold them together and make a secure connection.
 Instead of insulating tapes, you may also use heat shrink tubings to hold the connections together. To do this, cut a 1.5 inch piece of heat shrink tubing and from one end insert one of the pins of the LED and from the other end insert one of the wires from the motor. This part of the wire must be clean from any insulating materials. You may also bend this end to give it a perfect fit in the heat shrink tubing. At this time use the flame of a candle, small torch or lighter to heat up the heat shrink tubing so it will shrink. Let it cool down before touching it. Excess heat can damage the LED, so keep the heat away from the LED bulb as much as possible.
 Repeat the above process with the second pin of the LED and the other end of the wire from motor.Heat shrink tubings size 1/16" in diameter are the best for this experiment; however, you may also use 3/32" or insulating tape. If you don't have any of such insulating materials, just make sure that the connections are secure and two wires are not touching each other.
 Test your generator with LED light To test your generator, hold it in your left hand in a way that the LED light is faced to you. Use the thumb and the middle finger of your right hand to spin the longer side of the rotor dowel. You should see the light flicker. Do not use a cordless drill to test the generator.

Connecting LED using terminal blocks:

 Another way you can connect LEDs to the wooden generator is using terminal blocks. Terminal blocks are available in different types and different sizes. The blue terminal block shown in the right has two pins at the bottom. Apply some glue to the bottom of the terminal block and then push it into the wood. The wood glue will dry in about 1 hour. The combination of the glue and pins will hold the terminal block in place securely. Sand the ends of the wire to remove the insulation. Then insert each end of the stator wire in one of the holes in the terminal block.
 In the same holes insert the pins of the LED. Usually one of the pins is longer than the other. If you want to connect only one LED, then you can trim it so both pins will be the same size. Tighten the screws on the terminal block so that both the wires and LED pins are secure. If you want to connect two LEDs at the same time, then the do not trim the legs. You must insert the short pin of the second LED in the the same hole as the long pin of the first LED. In this way the long pin of the second LED will go in the same hole as the short pin of the first LED.

With this arrangement the LEDs will lit alternatively.

Terminal blocks may be purchased from local hardware stores.

Doing an experimental Science Project?

Making a working model of an electric motor by itself is a good educational activity and a perfect display project; however, if you have selected this subject as an experimental project, you will need to perform experiments in order to find answers to a specific question about electric motor. Following are samples of questions that may be studied as an experimental science project.

How do the material used in the construction of an electric generator affect the production of electricity?

How does the number of loops of wire in the coil affect the amount of electricity?
 Experiment: While winding wire around the generator, count the number of turns you wind. After 100 turns, make a small loop on the wire, twist it, and label it as 100. Hold the loop toward outside so you will not lose it after winding more wire. Continue to wind the second 100 turns. Make another loop and mark it as 200. Continue to wind the third 100 turns. Make another loop and mark it as 300. Continue to wind the fourth 100 turns. Make another loop and mark it as 400. Continue to wind any remaining wire and label the end of wire with final number of loops. For example if you made 15 more loops, label it 415. Sand the area of all loops as well as the beginning and the end of the wire. Get a volt meter or multimeter and set it to the lowest range of AC Voltage. Connect one probe of the meter to the beginning of the wire coil on the generator. Connect the generator to an electric drill (not battery operated drill) and start the drill while holding the generator. Ask your assistant to use the other probe of the voltmeter to the loops 100, 200, 300 and 400 while reading the voltage on the meter. (If you don't have an electric drill, just spin the rotor with hand as fast as you can. Observe the voltage. Repeat that a few times for each number of loops and then record the average. You may not need an assistant if you are not using an electric drill.)

How does the diameter of coil wire affect the electric current?
How does the speed of turning affect the production of electricity?
How does the diameter of wire coil affect the amount of electricity?

After you select your question, you must come up with an educated guess about the results. That will be your hypothesis.

Finally you will perform experiments and enter your results in a data table. You may finally use your results to make a graph.

Sample question 1:

While making the wooden generator, I noticed that wood is fragile and can not be used to make long lasting generator. I am wondering if metals, plastics or strong cardboards can be used instead.

Sample Hypothesis 1:

Plastic and cardboard boxes will function as good as wood and they may offer a better mechanical strength and durability. Iron and steel will attract the magnet and may redirect the magnetic field. With no magnetic field on copper wires, we will not have any electricity. Aluminum and copper can not be magnetized and magnetic field can pass through them. I expect a strong working electric generator with a box constructed from copper or aluminum.

Sample Experiment 1:

Construct five identical generators with five different materials for the box. Use the same type and length of wire, the same size and shape magnet, and finally the same shape and size axle for all generators.

Spin the magnet (rotor) at a constant speed and use a voltmeter to measure the voltage. Record the voltages in your data table.

Note: You may use an electric drill to spin the axis at a constant speed.

Sample Results table 1:

 Box Material Produced Voltage Wood Cardboard Aluminum .......

Sample question 2:

While making the wooden generator, I noticed that instructions recommend to wrap the wire at least 200 turns around the box. I am wondering why more than 200 turns? How does the number of loops of wire in the coil affect the amount of electricity?

Sample Hypothesis 2:

As the number of loops of wire increase, more free electrons in the wire will be in magnetic field. As a result by increasing the number of loops, more electron pressure will be produced and the produced voltage will be higher.

Sample Experiment 2:

Construct four identical generators with four different number of loops of wire on the box. Use the same type of wire, but turn the wire coil as follows:

• For generator number 1, wrap 50 turns of wire.
• For generator number 2, wrap 100 turns of wire.
• For generator number 3, wrap 150 turns of wire.
• For generator number 4, wrap 200 turns of wire.

All other specifications on four generators that you construct must be the same.

On each generator, spin the magnet (rotor) at a constant speed and use a voltmeter to measure the voltage. Record the voltages in your data table.

Note: You may use an electric drill to spin the axis at a constant speed.

Sample Results table 2:

 Loops of wire in the coil Produced Voltage 50 100 150 200

What is happening?

When the magnet (rotor) spins inside the coil of insulated copper wires, the free electrons inside the wire are pushed back and fort. When these electrons are trying to pass through very thin filament of the light bulb, they will create such a high amount of friction and heat that will produce light.

 COMMON MISTAKES / Questions and Answers Q: My son and I just put the Wooden Generator together. It doesn't work? A: Did you remove the insulation of copper wire at contact points with the light bulb base? Note that the insulation of these wires are almost invisible. You must use a sand paper or a sharp object to remove them. One other thing that I can think of is that wires should be as close to the dowel as possible. If you spread wires along the box, reverse voltage will be formed that cause problem. Q: My generator did not work with the 2.2 volt light bulb that I received in kit. I then used a 1.2 volt light bulb and then it worked fine. Why don't you supply 1.2 volt light bulbs with the kit? A: You are right. 1.2 volt light bulbs can light up much easier; however, they may burn if you turn the dowel very fast (with a drill for example).
 This generator worked fine; however, it has two problems.  The first problem is that the box is not strong enough. Some edges are clearly open due to insufficient use of wood glue. The other problem is that box is being crushed under the pressure of wire. This happens when the wire coil is crossing the wood fiber. Wood has its highest strength along its fiber; so, you must also wrap the wire along the wood fiber.
 This one is a total failure. The box is crushed and the wire has no insulation. I am not sure if the builder bought bare wire or he removed the insulation from the wire supplied with the kit.  A coil of bare wire is really one chunk of copper with no special order for moving electrons. Bare wires cannot be used to make a generator.
 People are creative. This one has only one coil. This coil is also crossing the dowel.  This generator worked, but, not as good as the original design. One problem was two much friction between the dowel and the coil.
 This also shows another failed model. The box has collapsed and one of the box walls is bent towards the inside of the box. This conditions does not allow the magnet to spin freely.
 In this model wire is crisscrossing the wood dowel while going around the box. Crisscrossing holds the wire coil in the center. This generator worked while spun with a drill. Due to high friction between the wood dowel and the coil, we could not spin the dowel fast enough to get light with fingers.
 Using an LED LED (read L-E-D) stands for Light Emitting Diode. LEDs need less electrical current than incandescent miniature light bulbs; As a result they light up easier. LEDs do not have a base. You can simply connect the pins or legs of LED to the two ends of your wire coil and secure them with tape.

If you don't already have a kit for wooden Generator, you can order it now. The materials in a kit are selected with care to ensure compatibility and successful construction of your project.