Wimshurst machine

WimshurstElectricMachine

File:Wimshurst Machine VGA.webm

Side view of homemade 12" Quadruple Bonetti Electrostatic Generator (Sector-less Wimshurst Machine)

Wimshurst Machine Charge Cycle

Wimshurst machine is an electrostatic generator used for generating high voltages, primarily invented by the British inventor James Wimshurst between 1880 and 1883. It is a popular device for demonstrating the principles of electrostatics in educational settings due to its ability to produce relatively high voltages and visible electric sparks safely.

Design and Operation

The Wimshurst machine consists of two large, counter-rotating discs made of insulating material, usually glass or mica, mounted on a common axis. These discs are placed close to each other and have metal sectors attached to their surfaces. As the discs rotate in opposite directions, charge separation occurs due to triboelectric effect and induction, leading to a buildup of electrostatic charge.

The machine also includes two Leyden jars or capacitors, which are used to store the generated charge. The Leyden jars are connected to the machine via metal brushes that make contact with metal segments or collectors positioned near the edge of the discs. The stored charge can be discharged as a spark across a gap, demonstrating the principles of electrostatic discharge.

Historical Context

The Wimshurst machine belongs to a class of machines known as influence machines, which generate electricity through electrostatic induction rather than direct contact or friction, distinguishing them from earlier devices like the Van de Graaff generator and the electrophorus. Its invention came at a time of significant interest in electricity and its potential applications, contributing to the understanding and development of electrical theory and technology.

Applications

Historically, the Wimshurst machine was used for various scientific experiments, including the study of X-rays and radio phenomena, as well as for powering early wireless telegraphy equipment. Today, it is primarily used for educational purposes, serving as a vivid demonstration of electrostatic principles such as charge separation, induction, and discharge.

See Also

• Electrostatics
• Van de Graaff generator
• Leyden jar
• Electrophorus
• Triboelectric effect