Monday, January 10, 2011


I finally got my hands on the solenoid-actuated valve I need for the pre-injector of my second railgun. Now it appears as though the manufacturer has discontinued that model starting this year. I hope my valve never breaks down or wears out. But at least that's one more hard-to-find/afford part that I can cross off my list.

The Mad Scientist Light Switch is finally nearing completion, although YET ANOTHER delay was created when my mill suddenly refused to operate. I suspect the motor drive, which provides 3-ph. power to the mill, has lost its mind after being unplugged for a week. One would think the manufacturer would use EEPROMs to store all the parameters, but apparently not. HOPEFULLY, reprogramming the drive will get me back up and running. I hope the drive isn't toast. That would be depressing, and would take a long time to fix.  If all goes as planned (and it never does) I should be done with that thing by the end of January.

Meanwhile, it looks like my first test shot on my switch will be about 30mS pulse time, 100 amps (or a bit less), 3kJ, 0.6C total charge transfer.  I'm eager to see the rise time.

I have realized that most of the ideas I had for connecting to the switch were bad, and I've decided to drill an additional six holes in each end cap to allow for bolted connections.

Once those are done (and the switch reassembled) my plan is to use copper pipe and plastic pipe to house the resistor, six half-inch wide copper straps to connect one end of the resistor to the switch, and six more copper straps to connect the copper pipe to the ground / return.  Crap: I just now realized that the way the pulse caps are connected to the parallel plate current collectors in the pulser makes it very difficult - maybe even impossible - to connect to the ground return plate.  I can either short the two plates at all four edges somehow (which would introduce extra inductance); remove the "hot" collector and insulating board from the stack (a huge pain in the ass and undesirable)... or find another capacitor with which to test my switch.  Grumble.

I'm really not interested in testing my switch with all six capacitors connected from the beginning.

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