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Building a Van De Graaff Generator
The Van De Graaff generator's components are fairly common materials, meaning it is possible for a competent craftsman to construct one at home. The design of the machine is simple, but the main challenge with a do-it-yourself VDG is finding the right combination of materials that yield the best performance. Furthermore, the buildup of charge is also sensitive to factors like sharp edges and moisture, which must be minimized to get a VDG to work effectively.
Purchasing a VDG: If you're not keen on the idea of a do-it-yourself project, you can buy a ready-to-run model. By popular demand, Storm Highway is now an authorized reseller of several high-quality Van De Graaff generators. Visit our Van De Graaff generator store for details!
Parts and Materials
Domes/spheres: Used domes (8 to 12 inches in diameter) from smaller generators can be found on the internet for as much as $200 to as little as $40 on auction sites. Some homemade designs have used two salad bowls or a paper mache ball covered in aluminum foil tape. Other possible ideas for domes include (safely emptied) small propane tanks, bowl-shaped charcoal grills, and large aluminum rice-cooking bowls (used in Chinese restaraunts). Whatever the material, it's important that any rough or pointed edges or protrusions be removed to reduce charge leakage.
Support column: The support column is the section that holds the dome, and must be made from an isulating material. Plastic or acrylic pipe works well. PVC pipe has been found to be a bad insulator that does not work as well. The belt also travels along the support column. When pipe is used, the belt usually runs inside the column. Some VDG designs place the belt outside of the column, in which case rods can be used in place of pipe.
Belt and rollers: The materials that make up the belt and rollers are possibly the most important consideration in how well your VDG runs. In most VDGs, the top roller is solid metal and the lower roller is made out of insulating material, such as resin or plastic. The belt must be made from an insulating material such as rubber or plastic. Surgical rubber has been found to be effective in VDG belt use, as well as silk fabric. Experiment with different belt materials to see which yields the best rate of charge buildup.
Charging combs: Charging 'pickups' at the top and bottom rollers can be made from wire screen, nails, needles, or even simply frayed-out braided wire. The charging points must be as close as possible to the belt, but not touching it.
Motor drive: The motor used to drive the belt can come from a multitude of sources, including anything from old AC vaccuum cleaner motors to new DC battery-operated motors. Van De Graaff machines can even be built to be driven by a hand crank.
Van De Graaff Generator Schematic
Diagram Key
- A- Hollow metal dome
- B- Dome/upper roller supports
- C- Upper corona discharge points (remove charge from belt), made from wire screen
- D- Lower roller- plastic or resin.
- E- Grounded sheet metal casing
- F- Insulating Belt
- G- Upper roller- metal pipe
- H- Upper roller axle, adjustable for belt tension control
- I- Electric Motor
- J- Lower corona discharge points (place charge on belt),
connected to ground (identical to upper corona discharge points)
- K- Motor shaft/drive axle coupling
- L- Gap cut in pipe for roller and axle clearance
- M- Slot cut in pipe for adjustable upper axle
- N- Lower axle (connected to motor)
- O- Drive axle bearing assembly
- P- Connection between dome and upper corona discharge points
- Q- Base (wood or plastic)
- R- 'Crowning' of rollers
Storm Highway :: Van de Graaff generator photo gallery
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