SparKit – Miniature Electrostatic Generator

Electrostatic Generator By Julian Phillips, Christchurch, New Zealand

This Wimshurst machine was designed using AutoTRAX for the circular spinning conductor wheels,

This is a project that I am launching on behalf of my 12 year old son, the following was written by him.

View Kickstarter page

The Start

There are a lot of cool scientific tricks and machines. But one of those stood out, the Wimshurst machine. A medium sized electrostatic machine  is capable of making around 40,000 volts, a large spark, and a nice cracking sound. But when I checked online they cost a lot. This is the story of my project.

It started as a year 8 science fair project (7th grade in the American system), when I made a Wimshurst machine out of mostly PCB Board, Unfortunately that project didn’t get any prizes, but I still liked the idea of a PCB Wimshurst machine. So here I am, some time later after a lot of testing, with my Product/Prototype. This machine is my first go at a commercial version and I still have a lot of designs in mind, but I’m lacking the support. So i’m hoping that this Product/Prototype will help me gain the extra support I need, to bring my other designs to life. Since I make slight improvements to this machine very often, so It may differ slightly from the machine shown in the picture.

Electrostatic Generator

How It Works

At this point you are probably wondering what a Wimshurst machine exactly is and how it works, to understand how a Wimshurst machine works, you need to know how an electrophorus works.

This is a diagram of an electrophorus.

Electrophorus Diagram

An electrophorus has a disk made of an insulating material which gets charged by a wiping it with a cloth (first image). A conductive disk with an insulating handle gets placed on top of the insulating disk (second image). The conductive disk will now have a charge on the side facing the insulating material of the opposite polarity to that of the insulating disk (electrostatic induction). The conductive disk gets grounded (third image). And the conductive disk gets taken away (fourth image), and the process starts again. In a Wimshurst machine, a small charge exists on metallic sectors on the disks. As the disks rotate past each other they induce charge on each other, (Similar to image two). The sectors then contact the brushes. (Similar to the ground wire in image three). The sectors move away from each other and the process starts again.

The History of the Wimshurst machine

The Wimshurst machine was developed by James Wimshurst between 1880 and 1883. It was developed for electrostatic demonstrations. There were many other electrostatic machines that had been previously made such as:

  • The Holtz Electrostatic Influence Machine (1865~1867)
  • The Toepler Electrostatic Generator (1865)
  • The Voss Electrostatic Generator (1880)

The problem with these machines is that the polarities can suddenly change and are therefore not as reliable, But the Wimshurst machine’s polarity does not change, making it a more reliable machine.

This machine is smaller than a regular Wimshurst machine and therefore will also output a smaller, and safer voltage which will mean that more people can explore this machine.

Specs

  • Height: Approx 140mm
  • Width: Approx 125mm
  • Terminals: Approx 80 mm
  • Disk Diameter: 120mm
  • Powered by two AA batteries

Parts

  • 2 PCB Frame Boards,
  • 2 PCB Disks,
  • 2 Motors,
  • 1 Battery Holder,
  • 2 PCB Stands,
  • 2 Spindles (with white ring),
  • 2 Terminal Rods,
  • 4 Nylon Spacers,
  • 2 25mm Screws,
  • 2 20mm Screws,
  • 4 Dome Nuts,
  • 7 Small Screws (1 spare),
  • 4 Plain Washers,
  • 2 Spring Washers,
  • 1 Switch,
  • 4 Charge Collectors,
  • 4 Brushes,

This is an instructional video that shows parts of the machine and will give you an insight about this kit set. The parts shown in this video may be different to the parts that you are sent as some improvements have been made. We have more parts coming and I will create a new video as soon as the new parts arrive very soon.

This is what the parts sent out to you will look like.

I am currently working on a electrophorus machine, and a kit of parts for some experiments. This will include a corona spinner, which is a small device that can be balanced on a terminal and will spin because of the corona or ion wind that flows from the intense electric field generated at sharp points

The Future

I would like to create a larger version of this machine that would be capable of more spectacular demonstrations, as well as other electrostatic machines.

Email Julian

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