Wimshurst machine

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Wimshurst machine with two Leiden bottles

A Wimshurst machine is an early influence machine for generating high voltage with the help of the influence . It was named after its British inventor James Wimshurst , who developed this machine in 1878.

construction

Functional diagram with charge distribution
Video animation of the reloading processes
Wimshurst machine in operation

Characteristic are the two vertically mounted, opposing and non-conductive discs on which there are conductive metal segments.

On each side of the two discs there is a "neutralizer" (see illustration: The neutralizer runs on the front from top left to bottom right), which connects opposing segments on a disc by means of pickups. After the metal segments have passed the neutralizers, the metal plates are electrically charged . Two consumers, one for positive and one for negative charge, then pick up the charge on the metal plates on both sides. The two poles are connected by a spark gap , which is formed from two opposing spheres.

The machine can be set to high output current or high output voltage by adjusting the neutralizers: With the neutralizers set to high (as shown in the figure), the machine delivers a high voltage (up to over 100 kV). If the neutralizers are close to the consumer (left and right), the output voltage drops and the possible output current increases.

The Wimshurst machine does not require an initial electrical charge to start, as there are always slight disturbances of the neutral equilibrium of the charge distribution. It is essential for the mutual reinforcement that at least two segments always influence charges in the segment that has just been diverted by the brush on the opposite pane. Only in this way is it possible at all for the charge to increase continuously. If only one segment were to occur as the exciter of the opposite, the influenced charge would always be exactly the same size as the initial charge and could never increase it. For operation, mechanical energy in the form of a rotational movement required. At the output a constant electrical current (some 10 µA) is available at a constant speed of the discs.

As with any other high-voltage source, the charge can be stored in high-voltage capacitors , which, like other historical electrotechnical devices, can be implemented in the form of Leyden bottles , for example . They smooth out the tension and this gives a slightly larger throw , i.e. H. the maximum air gap that can be bridged by the spark, as well as a higher discharge current. While you can only hear a faint crackling sound without capacitors and the flashovers can only be observed in the dark, loud, bright sparks can be generated with storage capacitors.

swell

  1. ^ Rankin Kennedy: Electrical Installations . tape V , 1903.
  2. ↑ hcrs.at: Influenzmaschine - How to get more out of your Wimshurst machine .

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Commons : Wimshurstmaschine  - collection of pictures, videos and audio files