Influence machine

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Influence machine (Wimshurst machine)

Influence machines are electrostatic generators , the voltage for generating the principle of separation of electrical charges through induction use. In contrast to electrodynamic generators , induction machines use the force of the electric field on electric charges.

Historical development and types

Electrophore

The Swedish physicist Johan Carl Wilcke first described the so-called electrophore in 1762 , which is considered to be the first influenza machine. Alessandro Volta developed it further in 1775 so that it could be better used for experiments. Due to its design, the original electrophore does not deliver a continuous DC voltage.

In 1865 Wilhelm Holtz mechanized the functioning of the electrophore in order to deliver continuous DC voltages. In the late 19th century traditional influence machines more durable and more uniform high voltage than the previously used electrical machines , the static electricity used.

Kelvin generator

Lord Kelvin found his own way of using influenz in 1867 with his Kelvin generator . In this so-called water drop generator, the influence of water drops is used to separate electrical charges, whereby voltages of up to 20 kV can be generated.

Wimshurst machine

From 1878 the inventor James Wimshurst constructed the Wimshurst machine named after him with several disks mounted in parallel on one axis and rotating in opposite directions, which could supply a continuous DC voltage. Among other things, it was used to supply power to X-ray tubes at the beginning of the 20th century. This enables voltages of up to approx. 100 kV to be generated. For higher voltages, the lengths of the insulation sections are no longer sufficient in typical structures and flashovers occur.

In the Wimshurst machine, the reciprocating movement is replaced by a rotating one in order to eliminate the forces of acceleration and braking.

Pelletron

Modern representatives of the influenza machine are pelletrons , which are used in particle accelerators . They are similar in structure to a band generator, but instead of a band they have an insulating chain to which pieces of pipe or balls are attached. Pelletrons can generate voltages up to 32 MV.

functionality

General

All induction machines are based on the principle of charge displacement and separation by means of influence , in that electrical conductors isolated from the environment are moved in the area of ​​influence of electrical fields. As a result of the effect of the electric field on electric charges in the conductive body, there is a charge shift within the metallic conductor due to the influence. Through a spatial movement of the metallic conductor, whereby work has to be done against the electrical field forces, combined with time-synchronized electrical contact and separation processes, which take place differently depending on the type of influence machine, direct voltages in the range of a few 100  V up to 100 kV are achieved .

Higher voltages cannot be achieved with simple demonstration devices because the insulation resistances of the structures are too low for this, and because there are also spray discharges such as corona discharges at the sharp corners and edges of the electrical conductors because the spatial distances are too small for higher voltages.

The efficiency is only a few percent. For this reason, induction machines as electrical machines, except in the field of training and as a demonstration device, have no significant technical significance.

Pseudoscientific Descriptions

Due to the sometimes not obvious functionality of influenza machines, rumors persist that effects outside of known physics are responsible for their function. However, no laws other than those known in electrostatics are necessary for this. In some sects and in parasciences , modifications of influenza machines are shown as the basis of drives for flying saucers (so-called “levitation disks ”) or as overunity machines for generating energy.

literature

  • Gottlieb Christoph Bohnenberger: Description of different electricity doublers from a new facility, together with a number of experiments on various subjects of electricity theory, etc. Tübingen 1798.
  • Wilhelm Holtz: About a new electrical machine. In: Johann Poggendorff, CG Barth (Ed.): Annalen der Physik und Chemie . tape 126 . Leipzig 1865, p. 157-171 .
  • Wilhelm Holtz: About the higher charge of insulating surfaces through side attraction and the transfer of this principle to the construction of influenza machines. In: Johann Poggendorff, CG Barth (Ed.): Annalen der Physik und Chemie . tape 130 . Leipzig 1867, p. 128-136 .
  • Wilhelm Holtz: To the influenza machine . In: F. Poske (Ed.): Annals of Physics and Chemistry . Julius Springer, Berlin 1904 (seventeenth year, fourth issue).
  • O. Lehmann: Dr. J. Fricks physical technique . tape 2 . Friedrich Vieweg and son, Braunschweig 1909, p. 797 (Department 2).
  • F.Poske: New forms of influenza machines . In: F. Poske (ed.): Journal for physical and chemical teaching . Julius Springer, Berlin 1893 (seventh year, second issue).

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