Well actually it only goes to 27 kV without the fluorocarbon 114 dielectric.

It’s huge! Shown next to a normal probe:

Just in time for the next run.

This is the same probe used in the Sydney experiment.

Today I made arduino control 30,000 volts.

My arduino has 3 channels of analog output 0 to 5 volt.

For testing I used this sin wave generator sketch:

int pwmPin = 9; // output pin supporting PWM

void setup(){

pinMode(pwmPin, OUTPUT); // sets the pin as output

}

void loop(){

float something = millis() / 1000.0;

int value = 127.5 + 127.5 * sin( something * 2.0 * PI );

analogWrite(pwmPin,value);

}

 

This generates a lazy 2 Hz sin wave.

But the output is not really analog, it’s pulse width modulation(PWM):

This tutorial shows how to smooth out  PWM using a low pass filter. My low pass filter used 6kΩ resistor and 4.7 µF @ 45V capacitor.

Here we have the raw PWM output superimposed with the filtered output:

Looks good!

Now we just add the voltage doubling op-amp circuit I made previously, and BOOM:

This shows the source signal and the voltage doubled signal.

Sweet! Now we can control the 30,000 volt glassman power supply.

Here the arduino is sending a slow sin wave to the glassman’s voltage control:

From 2011-09-10

The Glassman’s slew rate is really slow without a load.

Here is the setup:

This will be positioned a safe distance from the reactor, so you can kill the high voltage from a distance. I’ll wire it up and test it today.

Here is an air plasma it produced:

With current limiting and good air metering, we can get a stable plasma. I notice you get a sense for the plasma just by _listening_ to the glassman. When the plasma is unstable the glassman softly clicks along with the plasma burst.

Backside, second from top:

To get full manual control, you wire the jumpers like this:

I’ve already had some success remote controlling the Glassman. Looks like I’ll be using digital potentiometers again.

Here is a un-enhanced photo of the plasma… it’s much brighter:

Also worth a mention – the same plasma can appear either blue or purple depending on ambient lighting and perhaps other factors. So we can’t trust the color in the photo without further controls:

We start by attaching a ground line directly to the overhead sprinkler system. First we scrape off the paint:

Then we attach this purpose made ground clip:

Here it is installed:

We are using 12 AWG insulated stranded copper. In addition to this pipe ground, we are also using outlet ground from two different circuits:

Ground each piece of rack equipment, and the rack itself:

Ground several points on the chamber, sled, and pump:

Here is the high voltage connection point with high voltage divider inside glass insulation:

Yesterday I realized that we can get most of the way there by welding together two off the shelf components:

This diagram refrences parts 9812107 and 9611005 from insulatorseal which is a subsidiary of MDC Vacuum. I’ve sent this drawing to insulatorseal for a quote. One problem is that part 9611005 is only rated up to 6kV so we will need a custom variant to get to the 10kV to 40kV range.

The idea with this setup is that the high voltage could come through a standard HV feedthrough and connect to the insulated tip of this feedthrough via a connecting wire: