Tesla coils are the brain child of the early 20th century scientist Nikola Tesla—a man with roughly 300 patents to his name ranging from arc lamps to a helicopter prototype. Although not all of Tesla's ambitious plans came to fruition, his legacy lives on as electricity enthusiasts are still hard at work building enormous Tesla coils. One group is actively seeking funding to build the world's largest pair of Tesla coils capable of producing arcs around 100 yards long.
The project, called the Lightning Foundry, is headed by electrical engineer Greg Leyh. A recent push for funding on the website Kickstarter fell through, but the group promises to continue building the coils as time and money permit.
Previously, the group has made impressive tesla coils on a slightly smaller scale. As shown in the video below, one such coil can send out 50-foot electrical discharges.
So what's going on with these machines? Tesla coils are a form of high-voltage transformer; in fact, voltages for the coils can reach over 1 million volts. The coils take the output from a transformer, bump up the voltage, and then produce dazzling discharge arcs that crackle in the air. Smaller, less powerful versions of Tesla coils are placed in plasma balls, which are common at science museums and demonstrations. Consequently, the electricity only discharges in the ball's gas—usually neon or helium—and doesn't discharge in the surrounding air.
Electrical discharge in air is more difficult, and Tesla coil enthusiasts hope that large-scale projects will help unravel some of the mystery behind lightning bolts. These projects can have interesting applications as well, such as the wireless powered vehicle in the video below. Tesla would be proud.