- Starting Restoration
- How the Faradic Battery Worked
- Staining and Polishing Pieces
- Re-wiring and Circuit Design
- New Brass Handles and Connectors
- A Shocking New Circuit
- It All Comes Together
This is an antique Portable Faradic Battery with rheotome that I purchased at an antique store a couple of years ago. I thought it looked very Teslapunk in its design. It is actually an antique medical device. The left side is the cover that flips down over the base seen on the right. There is a metal cover inside the lid (right) that opens with instructions on the surface. Underneath, the cables and accessories are stored. For a little background check here.
The cables above are inserted into the connectors. The brass tubes in this picture would have been attached to the wood handles. The other end of the cables would have been connected to the brass/wood handles. When you would turn the unit on you could hold the brass tubes and get a mild electrical shock. This was supposed to do great things for your health.
It is in very rough shape. The box is cracked and the cover is disconnected from the bottom. Since it was in such bad shape, I felt I wouldn’t be destroying anything if I restored it to original condition with some embellishments.
This is a close up of the metal cover that goes inside the wood top. There is an instruction label here. You can see kinks in the metal cover from being bent at some point in history.
The top of the cover has a corroded handle and the wood is pretty dirty.
This is a side view of the bottom with the coil and other hardware removed. You cannot see it here but the bottom seams were separated probably from moisture exposure at some point.
Starting Restoration Faradic Battery
I clamped and re-glued the bottom to repair this damage.
This is the rest of the unit disassembled.
How the Faradic Battery Works
This is the inside of the control surface. The wiring looks pretty simple. The coil appears to have served as a step up transformer and relay at the same time. Two batteries would have been held inside the bottom of the box. Probably between 6 and 12 volts each. You would set the switch to use one or both batteries. One being low power and two high power modes.
When switched on the battery would energize the primary coil. This would act as an electromagnet at the same time pulling open the spring switch above on the left. This would open the switch and de-energize the coil. This would turn the switch back on along with the coil. This process would turn the coil on and off continuously, like a buzzer. Meanwhile the secondary winding would have a higher voltage induced into it from the primary. Probably some where between 40 and 60 volts AC at a lower current. This voltage is what would have been applied to the cables and that you would feel as a shock if you held the brass tubes.
This is the box after gluing and sanding.
Staining and Polishing Pieces
The box was then stained with red oak color stain.
This is the control surface with all the electrical hardware removed. On the right I varnished the surface after cleaning in order to hold the old black paint in place.
The hinge and latch hardware before and after polishing.
This is the handle after cleaning and polishing.
The box has also been varnished in this picture.
Here the hardware has been re-installed onto the base cover. In doing this I managed to break the fine secondary wire pointed to in a picture from the wiring shown earlier. If I want to make the system work, and I do, I will have to come up with a work around. With the primary coil still working the unit will still buzz from the spring switch turning on and off. It just won’t shock anybody until I can find a fix. I really don’t want to have to rewind the coils.
This is the metal lid inside the cover remounted. I flattened out the kinks and applied a coat of varnish to the outside (non-label side) to prevent further paint chipping.
These are some views of the hardware reattached to the box. I uses small #0 brass wood screws instead of the nails that were used originally.
The restored box closed.
And open. The black piece is not screwed in place here. Brass screws will be used to hold it in place. You can see the holes for the screws on the surface in this picture.
Rewiring the Electrical Parts
This is a short video of the unit energized. Next up is finding a way to supply the shocking voltage to the brass tubes now that my secondary coil has lost contact with the outside world. I will also polish up the brass tubes and reattach them to the wood handles. The wood handles will be sanded, stained and varnished as well. I will also try to restore the cables as best as I can.
Today I worked on refinishing the handles. The one on the left is how they started. I used paint stripper to get them down to bare wood. Then I re-stained and varnished them.
I found this picture on line and it is from a similar unit. It looks like the handles had some cloth pads that screwed onto the ends, so they were separate from the brass tubes. I guess you would soak the cloth disks in salt water so they would conduct.
I also polished up the brass tubes. They were originally chrome plated, but I will leave them brass. I will also add some brass connector plugs to the ends.
This is a view of the way the wires looked on the unit. I tried fishing in the hole on the top left in order to find the end of the secondary wire, but wasn’t successful.
Here I cleaned up the wires and added plugs for attaching to the battery. I am going to use just one battery so I wired the high and low power lines to the same connector. This will turn the unit on whether set to position one or two. Looks like I’m just going to have high power mode.
This is another view where the battery plugs are more clear (lower left). The black and red wires are to power my electric shock transformer. The yellow wire will act as a trigger for the shock circuit I need to design. The yellow wire will be attached to the energizing line going to the separate shock coil. The small “wall wort” transformer visible on the right will be used as the step up transformer for providing the shocks. It is a 120VAC to 24VAC unit. If I use the secondary as the primary I get a 5:1 increase in voltage. For 12 volts that will step up to 60V. The coil on the Faradic battery is about 1.5 ohms. The coil on my wall wort is about 15 ohms. If I try wiring the coils in parallel the Faradic coil energizes, but the wall wort/ shock transformer doesn’t get enough current to feel anything. If I wire them in series, most of the voltage drops across the new shock coil primary without enough voltage left the activate the Faradic coil. So I will be wiring the shock coil into a separate circuit that uses the yellow wire to trigger an FET transistor, which will turn on and off my new step up transformer. This should provide a pulsing input current to the shock coil.
This is the size of sealed lead/acid cell battery I will use and its placement. I will make some kind of bracket to hold it in place. This will make my Faradic battery rechargeable. That’s all for today.
Brass Handle Fabrication
I actually got quite a bit accomplished over the last week. The first things I worked on were some embellishments to the brass tubes and the wood paddle handles.
I took some brass rod stock and drilled, cut and threaded one end to accept a 6-32 brass screw.
The other end was drilled to accept the connectors on the cable ends.
These brass rods were then screwed to the existing brass tubes. This makes for an improved connection. This wasn’t original to the piece, but it makes for a nicer look and better attachment.
To act as paddles/pads for the ends of the wood handles I used these brass gears. These pads were missing from my unit and would have been much larger in the original. They are smaller in diameter, but they will fit in the cover without having to remove them from the handles.
I want them to be disks not gears to I mounted them to this screw.
Then turned them on the lathe.
And then I had disks.
I cleaned them and applied rosin. I then inserted two brass screws that I held in place with zinc nuts. Then the screws were soldered into place and the zinc nuts removed.
Here they are when first soldered and then cleaned.
I filed the screw heads flatter. The disks will be wrapped in cloth like those pictured above and I didn’t want too large of a bump in the fabric. I may machine these flat before I am done.
Here the paddles are attached to the handles.
A Shocking New Circuit
The next part was a bit of trial and error. I wanted to switch my step up transformer on and off using the pulse from the Faradic battery primary circuit. Here I was using a “bread board” for the circuit design.
This is the schematic of the circuit once finalized. The portion on the left is the existing rheotome circuit in the Faradic battery. The parts in the middle and on the left are the FET switching circuit attached to the step transformer. The line labeled “hot” delivers a low current stepped up AC voltage of around 30VAC. It’s enough to feel, but not enough to be painful. This circuit could be made very hazardous if you used the wrong components. Do not duplicate this unless you really know what you are doing. I have a degree in physics coupled with about 40 years of electronics hobbiest experience. In other words.. “Don’t try this at home!!”.
This is the transformer I used as the step up transformer. It normally is a step down transformer from 120VAC to 24VAC. By using the secondary winding as the primary I was able to get a 5:1 step up in voltage.
This is the same transformer with the cover removed. Next I need to mount all this circuitry inside the wood box. Then add some finishing touches. I will keep you posted.
The bread boarded circuit was transferred to this PC board before final assembly.
Before moving forward with mounting the electronics I did tidy up a few things.
You can see in this picture that the cloth on the cables were frayed in some areas.
I didn’t want to replace them or lose the fabric look, so I used heat shrink tubing to lock the frayed sections in place. They shouldn’t get any worse now.
I didn’t like the screw head look of the paddles I fabricated so I chucked them up in the lathe and turned them down.
Here they are remounted to the handles.
I decided to mount the transformer and PC board to this piece of 1/4 inch plywood before mounting it in the Faradic Battery box.
Screws were inserted into the plywood base, for holding the transformer and PC board in place.
This is the completed assembly ready for mounting.
Here it is screwed into place in the box.
I used barrier strips to attach the wires.
Two metal clips were used….
to hold the battery in place.
Next I wired the cover plate into the battery and shock coil circuit.
Then plugged in the battery.
It All Comes Together
The top plate was then screwed into place.
I left the ground contact black, but placed a red dot below the 12 volt contact and a yellow dot under the high voltage shock connector.
A couple of views with everything mounted.
Some stick on felt pads were added to the bottom.
And added these rubber bumpers to the back. These also are not original..
but the bumpers allow the top to swing back while protecting the hinges.
The ground line on the lower surface shown above only connects to the negative terminal of the battery when the unit is turned on only. I added this extra ground post that connects directly to the battery so I could clip the charger cable onto the battery from the outside. Again not original.
Here the unit is set up to charge the sealed lead acid battery.
The completed Faradic Battery with the top closed.
Here the top is open, but the metal lid is closed.
With the metal lid open you can see where the accessories are housed.
The completed unit set up to shock.
One more with everything laid out.