it works like this: you know how when you scuff your socks on a carpet, and then get that nasty shock by a door knob? Or how rubbing a balloon in your hair will cause the balloon to cling to the wall? Well a Van-De-Graaff generator is a automated version of this effect, known as the “triboelectric” effect. As the belt on the generator come in contact with the bottom roller, depending on the material used, the belt and roller will gather opposite charges. The charge on the belt is then carried up to the top roller, where it is deposited onto the sphere.
in this Instructable, I will show you how to build your own Van De Graaff generator, so you could be a mad scientist too!
Step 1: Step 1: The parts and tools
*lots of duct tape and electrical tape,
*a top load,
*a plastic tube about the size of a marker, (and yes, you could use a gutted marker too),
*a wide rubber band,
*a small motor (preferably with a long shaft),
*a power supply to power the motor
*some paper clips
*something soft and insulative to mount everything to. I used a white-board eraser
as for the tools, you will need:
*a soldering iron,
*wire cutters (recommended)
*hot glue gun or rubber cement,
*scissors and a sharp knife
Step 2: Some dangers:
Step 3: Building the generator
Next, we need to take our motor, and cut a piece of electrical tape a little wider than the rubber band, and wrap it around the shaft to make the bottom vinyl roller. Solder some wire to the motor contacts, and add some hot glue on the exposed contacts to insulate them and prevent corona.
next, shove the rubber band down into the tube. make sure it is aligned with the two holes. now take your motor and fit it tightly into the bigger hole. make sure the shaft goes though the middle of the rubber band and that the motor shaft is vertical with the tube. (one way to ensure this is to press the motor up against the plastic leaving no space.) now hot glue it into place.
Take the fuse, and touch your hot soldering iron to the end cap. the heat should make the cap fall off after a minute or so (tip: put a blob of solder in the iron to make this easier) after you have done this to both caps
unbend the paper clip, and then bend a 90-100 degree turn in it almost in the middle. grease up the paper clip near the bend, then take the glass roller and slip it down the clip. carefully, take a pair of pliers and make another bend the same as before, it should be so that you could tape the two ends to the tube. the top roller should look like a \''''/ shape, the ''"" being the glass piece. lastly, bend the very end upwards so corona will shoot towards the top piece, instead of shooting to ground. this will help prevent unwanted arcing and leakage
Slip the other end of the rubber band over the glass roller and secure the two ends of the paper clip brace to the end of the tube furthest away from the motor. I used duct tape, but hot glue should work too. The top roller should be as close to as parallel to the bottom shaft as possible. Test to see how well the rubber band moves around. If it immediately moves one to one side and gets stuck, adjust the paper clip until it stays centered.
Now add the brushes. stripe some wire about a 1/2 an inch (1 cm) off, and separate the bristles out as shown in the picture. Do this to two wires, each about 3 inches long or so. Strip off the other side about a 1/4 inch (6 mm) and put a solder blob on them to prevent sharp edges. Mount the first wire to the top, and have the bristles very close to the rubber belt, but not touching (even though having it touch will increase the output, it wears out on the belt quick. you can see distinct lines in my belt where the wires touched the belt.)