The Wimshurst influence machine is an electrostatic generator, which is a machine for generating high voltages. It was developed between 1880 and 1883 by British inventor James Wimshurst (1832–1903).

The machine has a unique look, with two large contra-rotating discs mounted in a vertical plane, two crossed bars with metallic brushes, and a spark gap formed by two metal spheres. 

Wikipedia offers the following description of the Wimshurst machine: 

“These machines belong to a class of electrostatic generators called influence machines, which separate electric charges through electrostatic induction, or influence, not depending on friction for their operation. 

In a Wimshurst machine, the two insulated discs and their metal sectors rotate in opposite directions passing the crossed metal neutralizer bars and their brushes. An imbalance of charges is induced, amplified, and collected by two pairs of metal combs with points placed near the surfaces of each disk. These collectors are mounted on insulating supports and connected to the output terminals. The positive feedback increases the accumulating charges exponentially until the dielectric breakdown voltage of the air is reached and an electric spark jumps across the gap.”

Effects like this were often used on old science fiction movies like Frankenstein to create large sparks in the laboratory setting. When the two counter-rotating disks are turned with the handle a static charge is stored in the Leyden jars which is eventually discharged across the gap between the two large spheres. The greater the distance between the spheres, the larger and louder the spark. 

Exhibit added: September 13, 2014 - Last modified: August 7, 2023

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