Baby Vandegraff Generator by Bruce Yeany 2001 https://www.youtube.com/watch?v=parq01q DKe4 http://www.instructables.com/id/van-de- Graaff-Electrostatic-High-Voltage- Generator/ https://www.youtube.com/watch?v=esz QS2GOMQE This small generator is able to perform most of the demonstrations that a larger one can perform. It runs on 2 D-cell batteries and can produce a 1-inch long spark but is safe to the touch. Materials: D-cell battery holder 2 alligator clips Soda can Toy DC electric motor 4 x 8 inch wood base PVC 1 inch to 1/2-inch adapter (for base) PVC tee joint 1 inch by 3/4 inch by 1inch PVC pipe 1 inch thin walled 3 and 3/8 inch long PVC pipe 3/4 inch about 1 inch long PVC 1 inch pipe coupling Rubber band 1/2 inch wide by 4 inch 1/4-inch nylon bolt 1&1/2 inch long and nuts Plastic tubing 1/4 inch inside diameter (pen) 1/8 inch bolt and nut 2 1/2 inches long Fender washer 3/16 x 1 inch diameter 5 inch copper wire made of several small strands Bruce s Science workbench A pilot hole is drill into the wood base. The 1/8-inch bolt is screwed upwards to secure the base of the generator. It should be cut off to a height of 1 and 3/4 inches.
The PVC adapter is placed over the bolt; the fender washer is then fitted over the bolt and into the top section of the PVC adapter. A nut is then screwed down against the washer the hold the PVC piece tight down against the wood base. A 2 D-cell battery holder can be attached to the wood base using two small wood screws. The two alligator clips should be soldered to the wires attached to the battery holder. These clips will allow for easy connection and disconnection of the power to the small motor. The motor needs to have wood dowel added to the end of it. The dowel is cut one inch long. It is 1/4-inch diameter. It needs a 1/16-inch hole drilled into it. Slide the dowel onto the shaft of the toy motor as far as possible without rubbing
The wooden shaft extending out of the motor needs to be covered with aluminum tape. The center needs to be built up using thin strips of the tape. This will help to keep the rubber band belt centered on the center of the shaft. The first strip is cut to 1/4 inch wide. The next strip is cut thinner. This strip is and 1/8 inch wide. And is layered on top of the first strip. A 1-inch wide strip of the aluminum tape is cut and then wraps over top of the center strips. It is one thickness of tape.
One end of the T connector should be sanded to allow for an easier fit onto the PVC fitting attached to the wood base. Sand enough of the plastic to allow for the connector to slide on and off with a firm push or pull. The T connector should be able to slide all the way onto the PVC adapter on the wood base with a little pressure. Some motors may not fit snuggly into the side of the T adapter. A 1 inch long piece of 3/4-inch thin walled PVC pipe can make a snug fit for the motor. Sand the inside of the pipe until the motor can slide in and out with a firm push or pull. An alternative method can be to wrap the motor with several turns of tape until the motor fits snuggly into the side of the PVC adapter. The short piece of pipe can now be slide into the side of the PVC adapter. The motor should fit snuggly into this short piece of pipe.
Check the fit of the motor into the side of the PVC adapter. The wood shaft should not touch the opposite side when it is all the way into its position. Use a hand saw to cut PVC 1 inch coupling is cut in half. Clean out and dry a soda can and remove the top tab. The cut side of the coupling is going to be glued to the top of the soda can. Follow the directions of the glue and apply glue to the top of the can and the cut side of the coupling
The coupling is centered on the top of the can. and allowed to dry. The edge of the coupling should be touching the can all the way around. The next step is to cut the one-inch thin walled PVC pipe to a length of 3 & 3/8 inches. Drill two 1/4-inch holes 2&1/4 inches from one of the end. The hole should be centered through the pipe.
Two small holes are drilled in the piping to firmly hold the wire in place. The size shown is 3/16 inch; the wire should be a snug fit into these holes. The size of the hole that you need will be dependant on the outside diameter of the wire. Measure in 2&9/16 inches from the end. The first hole is perpendicular to the larger 1/4 hole. Another angle shows the hole perpendicular to the 1/4-inch holes The second small is drilled about 5/16 inches away from the first hole.
A piece of plastic tubing is cut to about 14/16 inch long. If tubing is cannot be located, glass tubing or a drinking straw can be substituted for this piece. The tubing should turn freely on the nylon bolt without too much play. If a soda straw is used, it may need to be replaced more often due to wearing out. The plastic tube is going to fit inside the 1inch PVC pipe on the nylon bolt. The rubber band will fit over the plastic tube. The easiest way to get it in place is to hold the tube inside the rubber band. Hold the tube via the rubber band inside the PVC pipe and position it close to the 1/4 hole that are drilled near the one end. When it is in place, slide the nylon bolt through the holes in the PVC pipe and plastic tubing. After it is in place, attach the nylon nut onto the bolt to hold it in place.
Slide the 5-inch wire through the small hole that is perpendicular to the bolt and plastic tube assembly. Use wire strippers and strip off about 1/2 of the plastic insulation Spread the strands of wire out and bend them slightly downward. They result should look something like a leaf rake. Pull opposite end of the wire so that only about 3/4 inch of wire remains inside the PVC tube. The correct position should have the ends of the copper wire positioned top center over the rubber band and plastic tube. The wire strands should be adjusted so that they are very close (about a half millimeter or 1/32 inch) to the rubber band but not touching it. These strands will pick up electrons from the rubber band. The closer they are to it the better, however, if they touch the rubber band, it will not work.
Slide the other end of the wire back into he PVC tubing through the second hole. Use pliers to pull the wire through the hole as tightly as possible. Use wire strippers to strip off about 3 inches of the plastic insulation off of this other end of the wire. Slide this assembly into the unsanded end of the PVC tee. The nylon bolt should be parallel to the motor shaft when it is in place. Reach in and grab the rubber band and stretch the end through the opposite end of the tee.
While holding the rubber band, slide the motor into position. Release the rubber band so that it is resting in the center of the The rubber band should be centered on the shaft. The raised tape will help to keep the rubber band centered when the motor is running. If the rubber band is too tight the motor will turn very slowly or not at all. Check it by connecting the battery to the motor. To loosen the rubber band, push the PVC tube further into the PVC tee. Slide the sanded end of the PVC tee onto the holding assembly. The rubber band should be very close to the bolt shaft but not touching it. It can be adjusted by listening the sound of the turning motor. If the rubber band is touching the shaft, it will slow the motor down. Lift it up slightly until the motor is running at full speed.
Bend the wire and slide the can on the top the PVC tube. IMPORTANT: The wire ends should be bent enough so that it will touch the inside of the can when it is position. This wire picks up electrons from the rubber band and deposits them on the can. If the wire does not touch the inside of the can it will not work at or have a very minimal charge. The Generator is now ready to test. Connect both alligator to the ends of the motor. The motor should run with a buzzing sound inside. If it is running too slowly, try loosening the rubber band by pushing the PVC tube further into the PVC tee. Another problem may be the rubber band making contact with the bottom bolt. Twist and lift the assembly up slightly until the motor is running faster. The easiest way to check for a charge is to hold the inside of the wrist about an inch away form the soda can. You should get a visible spark. If not pull the can off and observe the running rubber band. Check to see that the little wire fingers are close but not touching the rubber band.