How to Build a 30 Kilovolt Wimshurst Machine!

by stevenliu7037 in Workshop > Science

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How to Build a 30 Kilovolt Wimshurst Machine!

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2020-21 Wimshurst Machine Demonstration
2020-21 Wimshurst Machine Demonstration Slow-Motion

*Figure numbers for pictures are shown once you open up the picture in the top left corner

The Wimshurst Machine belongs to a class of electrostatic generators called influence machines, which separated electric charges through electrostatic induction or influence. Electrostatic machines create high-voltage charges without the familiar coils of copper wire, permanent magnets, and commutators found in conventional generators. They’re made of brass, glass, and wood, and they look more mechanical than electrical.

The coolest thing about these generators is that you can feel them working. As you crank a Wimshurst Machine, you can hear it crackle with energy, you can smell the sharp tang of ozone, and you can feel the hair on your arms stand up as the Leyden jars begin to charge.

James Wimshurst invented the Wimshurst Machine in the late 1800s. It is a “simple” high voltage generator and can be used in experiments. It superseded other devices such as the "Holtz" and "Voss" machines. It was one of the first ways to generate high voltage to more or less conveniently take Röntgen pictures around the turn of the century. The Wimshurst machine was superseded around 1924 by more practical generators such as the Marx generator, which is still used today in laser printers and CRT television (Although those are becoming obsolete too). [1]

The Wimshurst Machine consists of its two iconic counter-rotating disks and two Leyden jars (capacitors). Most often, it is powered by a hand crank, but it can also be powered by an electric motor.

This instructable will show how I designed and built a full-sized Wimshurst Influence Machine from scratch.

My particular Wimshurst Machine generates 30,000 Volts (calculated using the maximum distance between spark gap) and produces several tens of microamperes, which is a rough estimate (with the Leyden Jars engaged).

Supplies

Estimated Cost: $150

Disk Assembly

(2) 12" x 12" x 1/8" Acrylic sheet

(1) roll of Aluminum Foil Tape

(1) 5/16" x 3' Acetal Homopolymer unthreaded rod blank (www.grainger.com)

Drive Assembly

(3) #258 Buna-N O-ring, 1 extra for backup (www.oringsandmore.com)

(3ft) 5/16"-18 Threaded Steel Rod

(4) 5/16" Set Screw Collar

(50) 5/16" Nut

(25) 5/16" Lock washer

(25) 5/16" Flat washer

(15) 5/16" Nylon lock nut

(12) 5/16" Fender washer

(1) M5 Screw and washer

(20 pack) 608-2RS Bearing (https://smile.amazon.com/gp/product/B07TWZ7X38/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)

Chassis

(1) 2' x 1' x 3/4" Plywood board

(2) 1.5" x 1.5" x 11.5" Wood board

(12) #6 x 3/4" Flat head Phillips wood screw

Electrical Assembly

(10 piece) 1/8” x 18" Bronze Brazing Rods (Ace Hardware)

(1) 4 ft. 1.5" Fluorescent lamp protector sleeve for the Leyden Jars

(6) #6-32 Cap Nut

(4) Alligator clip, 1.25"

3D Printed Parts:

Various 3D Printed Parts Attached

Print using: a perimeter of 4, infill of 15%, layer height of 0.2mm. This will make the prints the strongest.

Alternatively, print using FormLabs Form 2 SLA 3D printer, which uses a different technology than standard FDM 3D printers. The resulting parts have a higher quality and are much stronger.

Tools:

  • Multimeter
  • Soldering iron and solder
  • Drill and drill bits
  • Wire strippers, wire cutters, and pliers, electrical tape, etc.
  • Measuring tape, ruler, etc.
  • Saw

*All the parts were bought from Home Depot unless specified otherwise

Experiments With a Wimshurst Machine

The Wimshurst Machine can be used in a wide range of experiments, from powering an x-ray to an electron microscope. Here are some specific things that can be powered using a Wimshurst Machine: [2]

  • Smoke precipitator for cleaning up residual smoke in the air
  • Laser
    • When lasers were first invented, they were often powered using a cheap and simple method such as a Wimshurst Machine
  • X-ray machine
  • First electron microscope
    • In the 1930s in Germany, the first electron microscope was powered using a Wimshurst Machine
  • Anything that requires a very high voltage but a low current

Safety!

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Overall, the Wimshurst Machine is very safe due to the extremely low currents produced, even with the Leyden Jars connected. However, cautionary measures must still be as a Wimshurst Machine can easily ruin electronic devices that are placed too near.

How Does a Wimshurst Machine Work?

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The Beginning: Charging the Sectors

Each disk is covered in metal sectors on the outward-facing sides. Everything begins with any sector that has a net charge, meaning they have an unbalanced amount of positive or negative charge. As long as the sectors are clean and dry, there's usually at least one that's charged. Let's say that the noted sector in Fig.3. on the front has a net negative charge.

This negative sector influences the sector that it faces on the rear disk, repelling negative charge to the far side of the rear sector (since like charges repel) and leaving the near side with a positive charge (since unlike charges attract). This process is called electrostatic induction. The Wimshurst Machine is called an influence machine since the charge on one sector influences the charge distribution in another sector. Note that even though the charge distribution on the rear sector is influenced, it still has a net negative charge since all the charge is still contained in the metal sector.

Neutralizing Charge

Fig.4. shows what happens next to the rear disk that has just been influenced. Each disk has a neutralizing bar facing it. Each end of the neutralizing bar has a brush that touches the sectors as they pass. There is an even number of sectors, which means that when a brush is touching a sector, the bar electrically connects that sector to another sector at the other end of the bar. The original negative sector can now push the negative charge on the rear sector even farther through the neutralizing bar to the sector at the end of the bar. This causes all three sectors to gain a net charge.

The reason why it's called a neutralizing bar is that from its perspective, it just neutralized the charge on the two sectors that it's touching. Even though these sectors have the opposite charge, in reality, the neutralizing bar only "sees" the surface charge, which is the same for both sectors.

Immediately After Neutralizing Charge

Fig.5a is a view of the situation immediately after neutralizing the surface charge on both sectors after the disks are rotated slightly away from the brushes. The first sector is left with a positive charge since the negative charge was just taken from it by the neutralizing bar. The second sector just received a negative charge from the neutralizing bar, so it is left negatively charged.

Repeat!

Now, we have 3 charged sectors: the original one that started the sequence of events, the first charged sector, and the second charged sector. In Fig.5b, the charged sectors on the rear are rotated more to where they face sectors on the front side just when these front sectors are touched by the neutralizing bar on the front side. The entire process repeats with sectors influencing charge in more sectors and so on.

Note that the influencing and neutralizing event causes one sector to make the sector facing it on the opposite disk become charged with an opposite charge. The original negative sector created a positively charged sector. Once the disk was rotated to the correct position, that positively charged sector went on to create a negatively charged sector.

Going to the Charge Collectors

The front and rear disks (which rotate in opposite directions) result in the charges shown in Fig.6 after the influencing and neutralizing event is repeated a sufficient number of times. If you look carefully, all the negatively charged sectors are heading to the left collector, and all the positively charged sectors are heading to the right collector. You will also notice that the sectors that have just passed through either of the charge collectors have had their charge collected and are now neutral overall. That is until it reaches the neutralizing brushes, where the influencing and neutralizing recharges them.

Collecting the Charge

The charge collector combs do not physically touch the sectors. Instead, they have sharp points that face the sectors and have an air gap between them. As an example, let's look at the left collector in Fig.7a. The negative charge on the sectors repels electrons from the points, leaving behind a positive charge. Electric charge tends to accumulate around sharp points. The positive charge crammed together results in a strong electric field in the gap between the charged sectors and collector combs. This strong electric field ionizes the air molecules and makes them conductive, forming a bluish-purple corona near the points. This conductive air greatly reduces the resistance that air normally has. This causes the negative charge on the sectors to jump across the gap to the collector, which leaves the sectors neutral again (Fig.7b).

The same process happens at the right collector, only with opposite charges. Since the sectors approaching the right collectors are positive, the sectors will receive electrons from the collector, making those sectors neutral again.

The Leyden Jars and Spark Gap

The rest of the circuit consists of a spark gap and two Leyden Jars, which are two cylindrical capacitors connect in series. The spark gap is also a capacitor, albeit a much smaller one than the Leyden Jars. It also has a dielectric (air) that breaks down easily. The spark gap and the chain of Leyden Jars are both in parallel with the collectors (Fig.8). A shunt is often used to easily connect and disconnect the Leyden Jars. By disconnecting the Leyden Jars, they are separated from the circuit, and the spark gap would provide the only capacitance in the circuit.

As seen in Fig.8, the collectors are acting as a power source to the capacitor circuit, with the spark gap acting as both a capacitor and a switch that shorts at a high voltage.

The charge that is collected from the sectors charges up the Leyden Jars and the spark gap. The Leyden Jars are designed to withstand a higher voltage than the spark gap, so if everything goes according to plan, the spark gap breaks down before the Leyden Jars do. Once this occurs, it produces a short circuit. All the accumulated charge in the Leyden Jars quickly dumps through the spark gap as a big ZZZZZZZAAAAAAPPP!!!

Main Parts of a Wimshurst Machine and Design

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The following are the main parts of a Wimshurst Machine:

  • Disk Assembly
  • Drive Assembly
  • Chassis
  • Electrical Assembly

We will talk about each of these main components and how to construct them in the steps that follow.

The Wimshurst Machine was entirely designed using Computer-Aided Design (CAD) within Autodesk Fusion 360 (Fig.9). Fig.10a/b pictures an image and a hand-drawn design of an existing Wimshurst Machine bought from a science supply company.

Disk Assembly: Components

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The following are the components of the Disk Assembly:

  • The Disks
  • The Bearing Assembly
  • The Axle

The Disks

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Disk Version 1

Originally, I used two yellow acrylic sheets that were cut on an Epilog Laser Cutter and Engraver (Fig.11b). Unfortunately, I overlooked the fact that I needed a hole in the center, so when I tried to make the hole I needed, it was slightly offset. This, together with errors during my gluing process, resulted in two extremely wobbly and unusable disks. Therefore, I decided to make two new disks using two orange acrylic sheets as that was the only other color that I had available.

Disk Version 2

Disk V2 had a diameter of 290 mm and is 1/8" thick. The five holes in the center are cutouts in which the Bearing Assembly (the next step) is secured. The center hole cutting design is the eighth version. Prototyping was done using the Laser Cutter and a scrap piece of 1/8" thick acrylic. V8 provides the best fit for the Bearing Assembly. The sector design is the eight version and provides the best dimensions to fit 24 sectors on Disk V2.

Disk V2 is essentially what powers the entire system and creates the charge separation.

To complete Disk V2, 24 aluminum sectors must be attached.

  1. Using the provided sector template, cut out 48 aluminum foil sectors from a roll of aluminum foil tape (Fig.12a/b).
  2. Space out the sectors around Disk V2 using the provided sector spacer (Fig.13a)
  3. Mark location of each sector using a permanent marker
  4. Tape sector directly onto Disk V2 using the markings as a guide (Fig.13b)

The Bearing Assembly

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The Bearing Assembly consists of:

  • Bearing Holder V7 (Fig.14b)
    • Printed using white resin on Form 2
  • (2) 608-2RS Bearings
    • 22 mm outer diameter
    • 8 mm inner diameter
    • 7 mm thick
  • Aluminum spacer between bearings

Originally, I used inline-skate wheels; however, I had difficulty cutting grooves into the hard rubber. Further, the belt ratio would not be big enough for adequate speed to build up in Disk V2. Therefore, I decided to design my own Bearing Holder, which significantly increased the project's difficulty. My preliminary, hand-drawn design is pictured in Fig.14a.

After going through 7 rounds of prototyping (Fig.15), I settled with Bearing Holder V7. Fig.14b shows a cut-away view of Bearing Holder V7.

Bearing Holder V7 uses a snap-in press-fit design with auxiliary support from hot glue. Theoretically, my design should allow the Disk Assembly to be wobble-free. Unfortunately, there was still a significant wobble during my initial build process. I discovered that this was due to a printing artifact of the Form 2 printer. There was an extra build-up of material that sanding would not be able to remove. To mitigate this problem, I used hot glue as a "spacer" on the opposite side of the material build-up (Fig.16). After multiple rounds of trial-and-error, both Disk V2s are nearly wobble-free.

The bearing assembly is attached to the axle to allow the two Disk V2s to spin with nearly no friction. This will enable a smooth and consistent rotation.

Follow these steps to complete the Bearing Assembly:

  1. Apply hot glue to a bearing and fully press into Bearing Holder V7 (Fig.17)
  2. Insert aluminum spacer (Fig.17)
  3. Apply hot glue to another bearing and fully press into the other side of Bearing Holder V7 (Fig.17)
  4. Use sandpaper to rough up the contact surface between the completed Bearing Assembly and Disk V2.
  5. Glue Bearing Assembly to Disk V2. Be careful to avoid tilting or misalignment, which will result in wobbly disks.

The Axle

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Axle V1

The first version of the axle was a 5/16"-18 Steel threaded rod. During my troubleshooting process, I replaced the Axle as I thought it was causing my Wimshurst Machine to produce a much lower voltage than it should. See the troubleshooting step for greater detail.

Axle V2

5/16" diameter Acetal Homopolymer unthreaded rod blank. (Fig.15)

  • Thread 1" in on both ends of the axle using a 5/16"-18 die

When I was completing this process, my finished rod ended up with threads that were misaligned to the axle. Unfortunately, I do not have a picture since I immediately wanted to test if it would work and (almost) permanently assembled it. It turns out that it does, in fact, work perfectly fine.

The axle is used to secure the two Disk V2s and allow them to spin freely in place. A spacer is also used between the two Disk V2s to allow free rotation. The spacer is the same size as the ones used inside the Bearing Assembly. Optimally, the two Disk V2s are as close as possible without touching. The Disk V2s are secured in place by using a set screw collar on each side

Drive Assembly: Components

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The following are the components of the Drive Assembly:

  • The Crank
  • The Drive Pulleys
  • The Drive Chain

The Crank

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I borrowed this crank design from a Thingiverse File. After contacting Jonas J. from JayMake, he sent me his design, which helped me greatly in my project. [3]

I modified Jonas's design to suit my uses and fit a 5/16"-18 threaded steel rod (Fig.17a/b).

Originally, the crank was to be printed using durable resin to minimize friction. However, all of the durable resin prototypes failed, so I was forced to use white resin instead.

I went through a total of 10 prototypes and settled on Crank V10 (Fig.17c), which provides the optimal performance. Some of the difficulties that I head with the previous versions include:

  • Threads are too tight, so attaching a threaded rod was very difficult.
  • Threads are too loose.
  • Structural problems
  • Printing artifacts

The Crank is used to rotate the drive axle and power the drivetrain. To operate, the crank is rotated clockwise when viewed from the rear of the Wimshurst Machine. The threads in a crank are designed so that the crank is tightened onto the driveshaft during operation, thus preventing it from ever becoming loose.

To complete the Crank and crankshaft:

  1. Tap Crank V10 with a 5/16"-18 tap
  2. Thread the steel rod into the threaded hole and secure using Blue Threadlocker (Fig.17b)
  3. Attach the knob to Crank V10 using M5 screw and washer.

The Drive Pulleys

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I borrowed the drive pulley design of Dr. Scott Peterson's Wimshurst Machine. Fig.10b (in one of the steps above) shows the measurements of the existing Wimshurst Machine.

The Drive Pulley's purpose is to create a high gear ratio to allow the Disk Assembly to spin much faster than the crank is being rotated. After going through 13 different versions, I settled on Drive Pulley V13 (Fig.19a). It uses a 5-spoke design, which provides the best balance between strength and weight (Fig.18a). The finished print can hold up a 200-pound person when standing on the flat surface with only the extended portion touching the ground. The drive chain, which is an O-Ring, fits inside the V-groove shown in Fig.18b.

Fig.19b pictures two of the 13 versions. Here is a summary of the changes that I made in each version:

  1. Item created
  2. 5 spoke design added.
  3. 5 spoke design finalized
  4. Added drive chain groove.
  5. Added pin hole
  6. Added fillets
  7. Added more fillets
  8. Changed to 4" diameter
  9. Increased fillet radius for easier removal from the print bed.
  10. Changed clearance 0.005 mm -> 0.015 mm
  11. Added center hub fillet (0.05 mm)
  12. Changed centerFillet to 0.02 mm
  13. Changed clearance 0.015 mm -> 0.01 mm

To secure the two Drive Pulley V13 onto the drive shaft, pressure-fit between two fender washers and secure using nuts. Originally, the pin hole would be used to secure the pulley onto the drive shaft; however, I realized that a pressure-fit would be much simpler and easier to adjust.

The Drive Chain

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The drive chain transfers the power from the Drive Assembly to the Disk Assembly through a belt and pulley system. Made using Buna-N material, the O-Ring acts as the belt to transfer the power. Two #258 O-Rings are used, one for each Drive Assembly (Fig.20). One of the two O-Rings is twisted to create counter-rotating disks, so the sectors move past each other. The O-Rings use friction to transfer power.

Installation of the O-Rings will be done after the chassis is completed:

  1. Attach the Drive and Disk Assemblies to the wooden posts
  2. Manipulate the assembly so that you can add the two O-Rings, one around each vertical set of Drive Pulley V13 and Bearing Assembly V7
  3. Remember to twist one of the two O-Rings. In my Wimshurst Machine, I arbitrarily chose to twist the front O-Ring.

The Chassis: It Holds the Thing

The following are the components of the Chassis:

  • The Base
  • The Supports
  • The Leyden Jar Supports

The Base

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It's Plywood

To make the base (Fig.22):

  • Drill two 5/16" holes spaced 4" apart and insert two 1.5" long 5/16"-18 threaded steel rods
  • Secure rod on top and bottom using nuts and washers
  • Attach anything you want as "feet" for the base. Since the nuts on the bottom stick out, there need to be "feet" to support the base.

These two posts that you just made will be used to secure the Wimshurst Machine Supports to the base.

The Supports

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Supports V1

Originally, I was going to 3D print a design that I created and pictured in Fig.9. from a previous step. However, I had difficulty manufacturing my 3D design since the Form 2 cannot print such a long piece.

Supports V2

Instead of a 3D printed support, I was forced to use a wooden board/post that I salvaged (Fig.23). Each Support is 11.5" x 1.5" x 1.5". I then drilled holes 2" deep into each support from an end (Fig.24). This allows the supports to be secured onto the Base using the two posts from the previous step. The outer 1/4" was expanded using a 1/2" drill bit so that the support can fit over the nuts securing the posts onto the base.

I drilled two holes on each support after clamping them together (Fig.23). The lower hole is 7/16", which allows me to insert and hot glue a sleeve to protect the wood from the steel drive axle (Fig.25). The upper hole (5/16") is used to hold the Disk Assembly.

I quickly realized that my original intention of just using the two posts to secure the two supports would not work. So, I decided to use four angle braces, two on each support, to help secure the supports to the Base (Fig.26). This would provide double security and guarantee that the supports will not wobble.

To prepare the supports:

  1. Choose the flatter and more stable end of both supports to be the base.
  2. 2.5" up from the base, drill a 7/16" hole
  3. Apply hot glue to an aluminum spacer (same as the ones used in the Bearing Assembly) and insert into the 7/16" hole
  4. 8.75" up from the base, drill a 5/16" hole

The original intent was to optimize the space, so I left myself very little clearance between the Drive and Disk Assemblies to work with. In the end, I was able to successfully work with the bare-minimum clearance to assemble the Drive and Disk Assemblies.

To assemble the Drive and Disk Assemblies:

  1. Attach supports to the base, but not permanently yet.
  2. Insert Disk Assembly Axle (with the Disk Assembly attached)
  3. Insert Drive Assembly
  4. Attach O-Rings as specified in that step.

The Leyden Jar Supports

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The Leyden Jar Supports are used to support the Leyden Jars. These two supports also are a crucial part of the Electrical Assembly, as they provide electrical connection between the various components.

To make the Leyden Jar Supports

  1. Cut two 7" long 5/16"-18 threaded rods.
  2. Drill a 5/16" hole 6" from each short edge (see Fig.28)
  3. Secure using the same method as the support posts.
  4. Bend any spare copper wire you can find into the shape shown in Fig.27
    • I used 18 AWG copper wire.
  5. Attach the bent copper wire to the Leyden Jar Supports
    • Note that the bent wire must make electrical contact with the inside of the Leyden Jars

Electrical Assembly: Components

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The following are the components of the Electrical Assembly and help everything go ZAP!:

  • The Neutralizing Bars
  • The Charge Collector Combs
  • The Discharge Electrodes
  • The Leyden Jars and Shunt

All of the conductors for the Electrical Assembly are made from the Bronze Brazing Rods unless otherwise specified.

The Neutralizing Bars

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Version 1

Bare Bronze Brazing rods bend in a wide u-shape (Fig.30). Alligator clips are soldered onto each end. Solder wick is clipped into each alligator clip to act as brushes that make contact with the sectors.

Version 2

During the troubleshooting process, I wrapped several layers of electrical tape around the center of each rod to prevent electrical conductivity.

Final Version

Removed the electrical tape since I mitigated the original problem using an Acetal rod instead of a steel threaded rod.

Repeat the following steps twice to make two Neutralizing Bars:

  • Bend an 18" Brazing rod into the shown u-shape
  • Make sure that the brushes will make contact with sectors on opposite sides of the Disk Assembly (Fig.31)
  • Once the design is finalized, solder alligator clips onto the ends of the brazing rods.
  • Cut strips of solder wick to make the brushes.

To attach the Neutralizing Bars:

Secure between two Fender washers and a nut threaded onto both ends of the Acetal Axle (Fig.32).

To align the Neutralizing Bars:

From both the front and back, the neutralizing bars should be roughly 30-45° from the collector combs.

A sector should pass through a charge collector, encounter a neutralizing bar after about 1/6 of a rotation, and then encounter the other charge collector after another 1/3 of a rotation.

The Charge Collector Combs

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The Charge Collector Combs, or Charge Collectors for short, are made using a long U-shape of brazing rod with 1 winding of 22 AWG Copper wire soldered on.

V1 used 12 windings, which inhibited the performance of the Wimshurst Machine. The 12 windings resulted in 12 pins sticking out of each side of the Charge Collectors (Fig.33).

V2 used only 1 winding. Unfortunately, I do not have a clear picture of V2. If you look closely in Fig.1, you will see that there is only 1 pin sticking out towards a sector on the Disk Assembly.

To make the Charge Collector Combs:

  1. Bend a Brazing rod into the U-Shape shown in Fig.33
  2. Attach 12 windings and solder on (Fig.34)
  3. Solder the sharp ends of the Charge Collector combs to produce smooth ends to prevent the accumulation of charge and corona discharge (Fig.35).
  4. Cut the windings to produce small pins (Fig.33)

To attach the Charge Collector Combs:

  • Secure between two fender washers on the Leyden Jar Supports

The Discharge Electrodes

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The Discharge Electrodes are constructed from two 18" Bronze Brazing Rods and #8-32 Cap Nuts, which are soldered on:

  • Bend into the shape shown
  • Solder on the cap nuts
  • Polish cap nuts using a Dremel with polishing attachment and Tripoli Compound

Polishing the electrodes will decrease the accumulation of charge in particular spots and encourages an overall charge accumulation. This would allow the gap to go off at a higher voltage.

When operating, space the electrodes approximately 1/2" apart.

The Leyden Jars and Shunt

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The Leyden Jars are essentially two layers of aluminum foil around a section of fluorescent lamp protector. One layer of aluminum foil is on the inside; one layer is on the outside. This creates a capacitor. The two Leyden Jars that I made were not perfect; one had a capacitance of 0.83 nF (Fig.38) and the other 0.76 nF.

To make the Leyden Jars, repeat the following steps twice:

  1. Cut a 7.5" length of the fluorescent lamp protector sleeve.
  2. Cut two 5" x 6" sheets of heavy-duty aluminum foil (Fig.39).
  3. Wrap the sheets around the tubes along their 6" axis so that each foil cylinder is 5" high (Fig.38).
  4. Tape the foil onto the inside of the sleeve
    1. I found that holding it in place with a sheet of paper rolled up into a tube works well.
  5. Tape another piece of foil onto the outside of the sleeve
  6. Press on the tube end caps that are provided when buying the sleeve.

To secure the Leyden Jars:

  • Slide on top of Leyden Jar Support.
  • Secure using a fender washer and nut.

To make the Leyden Jar Shunt:

  • Use 14 AWG copper wire and bend into a shape to smoothly touch both Leyden Jars simultaneously. See Fig. 40.
  • Secure the shunt onto the base using 3D printed "Shunt Holder."

Troubleshooting

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Originally, my Wimshurst Machine was only producing a maximum of 200 Volts. To fix this, I used the "stare-at-it" method for 30 minutes, and it worked... partially.

I realized that the two neutralizing bars were electrically connected through the Axle V1, which is steel (Fig.41). First, I added several layers of electrical tape to the neutralizing bars where it contacts the fender washers (Neutralizing Bars V2). However, this did not help at all.

To eliminate all possible problems, I replaced the axle with a highly-insulating material: Acetal Homopolymer. I also removed the electrical tape since it made assembly much more difficult and was not helping. After these adjustments, which should have helped, the voltage actually decreased to less than 100 Volts!

This may have been due to various reasons, but most likely, I accidentally bumped the charge collectors and moved them out of alignment.

My instincts told me that the Charge Collectors might be at fault.

I hypothesized that the Charge Collectors should have fewer tips instead of more. To test this hypothesis, I made two more Charge Collectors with only 2 tips. This significantly increased the voltage to the point where a spark occurred! I then reduced the number of tips to only 1, and Charge Collector V2 was born.

The reason why reducing the number of tips helped is based on the same principle of how the Charge Collector Combs Work. The pointy tips of the Collectors create a strong electric field that causes corona discharge. The magnitude of the electric field is inversely related to the area of the tips. The goal is to maximize the electric field, thus maximizing the voltage by minimizing the total area. However, having more tips completely goes against the goal of minimizing area.

By only having one tip on each side of the Charge Collectors, the area is at a minimum and voltage at a maximum. This optimizes the efficiency of the Wimshurst Machine and allows high voltage electricity production.

IT WORKS!

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Things I Learned

The most important knowledge that I gained from designing and building my own Wimshurst Machine is the process of designing and manufacturing.
Previously, I have taught myself how to use Autodesk Fusion 360. I applied my knowledge to this project, and I quickly came up with an initial design. However, I significantly underestimated the difficultly of finalizing a design.
Throughout this project, I have designed and tested 78 prototypes ranging from printing processes to structural integrity. I now understand that designing a model is simple; however, designing a model to the right specifications that operates without faults is much more tedious and time-consuming. I was nearly consumed in the endless prototyping stage, but I realized that I must stop at the better product as it's impossible to create the best.

Citations