Van de Graaff generator
Other electrostatic machines like the Wimshurst machine or Bonetti machine work similarly to the Van De Graaff; charge is transported by moving plates, disks, or cylinders to a high voltage electrode. For these generators, however, corona discharge from exposed metal parts at high potentials and poorer insulation result in smaller voltages. In an electrostatic generator, the rate of charge transported (current) to the high-voltage electrode is very small. After the machine is started, the voltage on the terminal electrode increases until the leakage current from the electrode equals the rate of charge transport. Therefore, leakage from the terminal determines the maximum voltage attainable. In the Van de Graaff generator, the belt allows the transport of charge into the interior of a large hollow spherical electrode. This is the ideal shape to minimize leakage and corona discharge, so the Van de Graaff generator can produce the greatest voltage. This is why the Van de Graaff design has been used for all electrostatic particle accelerators. In general, the larger the diameter and the smoother the sphere is, the higher the voltage that can be achieved.
Electrohydraulic forming
Electrohydraulic forming (EHF) is based on the ultra-high-speed deformation of metal using shockwaves in water. Using the discharge of current from a capacitor bank, an electric arc is generated in water between two electrodes. This electric arc vaporizes the surrounding water, converting electrical energy into an intense shockwave of mechanical energy.
The shockwave simultaneously transforms the metal workpiece into a visco-plastic state and accelerates it into a die, enabling forming of complex shapes at high speeds in cold conditions. All of which happens in a matter of milliseconds; total cycle time of seconds including charging time of the system. This process is not limited by size and allows forming of parts up to a few square meters in size. An array of electrodes can be placed over a large workpiece, enabling pressure distribution according to the product’s topology, still using a one-sided die to create complex shapes and fine details.