Introduction: Replacement Discs for Wimshurst Generator and Small Housing for Signal Generator Board FY3008S
I plan to do some demo’s with this equipment to entertain kids with high voltage experiments.
But this Wimshurst generator had broken discs and a nasty crack in the bottom plate.
Bottom plate could be easily fixed. (Some glue and fixing the whole on a slightly larger plate MDF 18mm thick made the bottom plate rigid again)
Step 1: Could the Generator Still Be Operational?
Discs were glued to check if generator could still generate high voltage sparks.
The “metal” surfaces were no longer conducting so from aluminium foil tape similar formed strokes were cut and put on the discs for only one out of two positions.
This proved the generator was still able to create arcs over about 50mm distance between electrodes.
Step 2: Cutting of the Strips
Each disc requires 24 aluminium strips.
To cut the aluminium strips a mold was made from an old plastic membership card.
With a metal pin the contour of the mold can be traced in the aluminium foil.
A scissor is used to finally cut the strips.
Step 3: Adding the Strips to the Discs
The original discs are very useful to mark the position for the aluminium strips on the newly cut discs.
(The original disc in this case fixed to the newly cut with some paper tape)
Step 4: Assembled Wimshurst Generator
With this repaired discs the generator looks brand new.
First test didn’t give any sparks. But cleaning the discs and a really dry environment resulted in a good functioning Wimshurst generator.
A next step could be to mount all parts directly on the MDF base plate but I preferred to build some additional things for the demo’s, e.g. a smoke precipitator
Step 5: Smoke Precipitator
Smoke precipitator build with scrap material:
Metal beer can with bottom and top removed serves as positive electrode at the top.
Plastic milk can cut to accept both electrodes.
At the bottom is a metal grid as negative electrode.
Some plastic tubes 5/8” at the sides just fixed with rubber bands make the precipitator in height adjustable.
Step 6: Top and Bottom Plate for Signal Generator Board FY3008S
Already several years this signal generator is used without housing.
In the future I expect to let children work with this signal generator so some protection of the board and easy connection would be nice.
This project was also an opportunity to make better use of the plexi plate (300x600mm) together with the 2 discs for the Wimshurst generator.
Step 7: Oops. Bending Failed.
The part of the bottom plate to mount the BNC connector was ment to be bent 90° but it broke off at the first attempt of bending.
The mounting holes for the generator needed also to be adjusted.
The corner of the bottom plate was restored as good as possible.
Step 8: Assembly - Top View
Top and bottom plate were painted black.
Top plate to cover the backlighting of the display.
Bottom plate to mask the restoration work.
Standoffs F/F M3 25mm long and screws M3 are used to assemble top with bottom plate.
BNC connector is mounted on one of the two small additional cut plexi plates and connected straight to the screw connector. Although this makes the other screw connections less accessible it seems to be the best solution for the moment.
Step 9: Assembly - Bottom View
The 4 silicon feet added at the bottom plate help to keep the generator better in place and avoid the screw heads to touch the table.
Step 10: Conclusions
It was not possible for me to bend this plexi. (Even after warming the part to be bent with a heat gun.)
It is better to foresee some slots in top and bottom plate to fix easily connection plates between these two.
Next time slightly larger and slotted holes could make mounting of board or parts easier.
Using cyanoacrylate glue to protect the display with the cut out plexi part was not a good idea. This glue left some vapour marks on the plexi in the corners of the display.