Prometheus Fusion Perfection

Fabricated the second row of capacitors. I have one capacitor left…so we can take it to 11 when the time comes!

Also received the capacitor clamps to make mounting easy:

And finally got 2A fuses for the power supply:

In other news, I got Windows XP running on my macbook on a separate partition. Also got LabView installed. More on that later.

I successfully fired the coil power supply’s SCR today. Here’s how: I started by grounding the chassis:

Later inspection revealed less then fantasic electrical conductance between the ground cable and the aluminum chassis.

Wired up the SCR and polywell coils:

For the triggering circuit I improvised with available parts. I settled on this circuit:

Looks like this:

I tested it out and it works!

When the SCR discharges you can see the coils flex and hear a sound from the SCR… and the voltage across the capacitors drops sharply. I took it up to 400V with 5 caps.

Pretty major step forward for the coil power supply.

Nest steps include:

Making a front panel with master power switch, AC indicator, capacitor  bleed switch, high voltage LED indicator.

On the back panel: IEC C14 AC connector, screw down terminals for coils power out, and D-sub interface for computer control (via DAQ). I want to computer control the AC power, bleed resistor and SCR triggering.

Stuart made a keen observation about a relay on the DC side: Relays have a much lower voltage rating for DC vs. AC. So a relay rated at 240VAC may only be rated at 30VDC. This is because DC sparks are harder to quench-  they don’t naturally drop to 0V like AC does. So long story short – I’m going to put the relay on the AC side of the transformer.

I also want to fuse the AC and DC sides.

I mounted the sheet aluminum on the 80/20 chassis:

And installed the new ground cable:

I cut the bus bar to length, and clamped two bars together to get good hole alignment. Then measured and center tapped:

Drilled and mounted:

Wire it up for a test charge. This time we are charging through a 1KΩ 50W resistor network. Everything seems to work as expected.

Wired up the protection diode:

Excellent day in the lab.

I got the elevator key copied, so I’ll never get locked out of the lab. I did a successful test of the mechanical relay.

I rearranged the equipment rack to make room for the coil power supply:

Using 80/20 I constructed a 4U rack mountable chassis for the coil power supply:

Next I mounted the electrical hardware on the sheet aluminum. I started by using a transfer punch to make guides for the drilling. Then I drilled and tapped the holes for M3 bolts:

The first circuit I wired up was the 2 KΩ bleed resistor. Here you can see the bleed resistor wired to the capacitor via a switch. Turning ON the switch bleeds the capacitor:

Next I wired the DC side to the capacitor while minding polarity. Put a voltage meter across the capacitor:

Using the variac I slowly brought up the capacitor to 300V:

Once the capacitor is charged… it holds its charge without much dissipation after the variac goes off.

I was planning to power the relay using this ATX power supply (24V across +12V and -12V):

But during my initial testing it started squeeling and soon blew its fuse!

There was no short circuit that I could see, so perhaps it just died of natural causes?

Anyway… it reminds me: I should fuse the  coil power supply before I go much further!

Received more capacitors from eBey. Eight total now. The last batch of parts arrive Tuesday the 6th.

Next step is to mount the electronics on an aluminum sheet. Although this is a relatively easy task… it feels daunting somehow. The smallest tasks are often the hardest for me.

Also made progress on the Kickstarter rewards:

Kind of interesting “spending time” with the patrons this way. I took a good look at each address to see the places this project has connected with all over the world. One reward is going to the NYC Google offices!