Thursday, December 10, 2009

Top sekrets!

For a while now, my company has been involved in some fun stuff, which I haven't been able to talk about mostly because of time, but also because it's been a well guarded secret. Which is not so well guarded anymore.

Because we have little regulation out here on the rim, we don't worry too much about trying new stuff. We also like to play with old stuff; we have had a good deal of luck (and made a good deal of money) by taking existing products and- well, making them perfect.

We can't do much with things like transistors, but we can make them very fast and very reliable, though they are plenty reliable enough to begin with. What we have had some fun with is the real high power stuff. One of the projects I was assigned is to try to make high power relay/switching systems work more efficiently.

We started with Klystron relays, and did some pretty impressive work; eventually we moved up to things like IOT finals. These are used in broadcast transmitters and other similar tpes of equipment. The crude ones are used to inductin harden special steels. The fine ones are used on stardrives, to push entire ships- er, outside, and then pull them back in again. It's an interesting thng- and a concept few entirely grasp- that FTL travel and broadcast communications share so many common technologies.

Anyway, one of my co workers George and I had the very first unit on our floor getting ready to test it. Part of the reason we can do such interesting work here is the purity of the materials we have to work with, and this is a huge help. We cast the final housing in vacuum so there would be no impurities, and machined it also in a vacuum to prevent the introduction of anything that would affect the drive.

The assembly took place in a clean vacuum- the vacuum of space is plenty empty, but anything near anything experiences contamination by outgassing. A solid piece of cast iron will, remarkably enough, give off, in it's lifetime, about tenth of a percent of it's weight in oxygen, carbon, nitrogen, etc. and these gasses- even in ultra tiny amounts, will eventually contaminate a high power final drive. We have rooms that have been evacuated by the vacuum of space, while the components in the room and the tools have all been outgassed elsewhere.

We assembled the first IOT final in the clean vacuum, and then put it in the centrifuge for a day. There are always a few molecules of crap floating around, and we have removeable "stickypads" that trap them and get them out of there. A lot of the time when you see burn or arc-over inside a final it's because there were enough molecles of contaminant floating around that it caused a problem.

Anyway, we put the final on the test stand and brought it into the test room.

There's a special fluid we use to cool these finals, and it has to come in at a pretty high pressure, and if there's the slightest void in the casting it can carry some of the coolant into the vacuum chamber. George hooks up the coolant and starts the pump.

'Sixty five pisseye" he reads. "Seventy. Seventy five. Secondary pumps kicking in. Ninety pisseye. One ten. One fifty. Two hundred. Coolant passages full and pressure holding. Dropping blast screen" The second test we'd done with this equipment there was a leak and the coolant breached through to vacuum- the drive, made to only deal with the 14.7 PSI of atmospheric pressure, popped like a popcorn kernel. George was doused with the greasy black c0oling fluid and barely avoided being impaled on flying shrapnel. "Blast screen secure. Five hundred pisseye. Six fifty- seven fifty- eight- nine- one thousand pisseye. Max pressure reached. Cutting in secondary pumps. " The next test uses a secondary, backup set of coolant passages, and it passes it's test with flying colors. We leave the system hooked up and under presssure for a couple of weeks, to make sure there will be no leakage and no crossover from pressure to vacuum.

The ultra purity of the materials and the cleanliness of the vacuum chamber and the components therein can affect it's longevity and the amount of power it can wihtstand, but it's also critical to the- er, higher uses.

Years ago, an engineer figured out you could use microwaves to cook food, and they made Magnetrons that did the job, only they made them like they were using them for broadcasts. Later, they discovered that food was not nearly as picky about the quality of the "Signal". The final drives that are used in space travel are the opposite- the first were made out of modified radio transmitters, but it was soon discovered they had to be more powerful and more meticulously tunable to be functional and reliable. A lot of fine booster techs out there were still wandering around with tiny non-conductive screwdrivers and field strength meters wearing holes in their coveralls because they had to constantly fiddle with the aging drives. These drives would- well, they'd never eliminate the need for techs, they'd just make their lives a lot easier.

SO we put the drive in the cabinet and hook everything up, and put on a dummy load so as not to squirt-boost the planet a hundred miles out of orbit, and turn it on.

It makes a little click noise, and comes online, a 2500 kilowatt unit in the same size case as a 250 kilowatt unit just a couple years ago. The power consumption is incredible, we're feeding it from line voltage direct from the nuke plant down the road, and though it's a separate circuit, the lights in the building dim anyway. We let it get to temp to make sure the cooling system works, and carefully shut it down.

It got burned in in a light cruiser doing long hops for test purposes only. george went with as tech. That was eight months ago; the first unit was delivered and installed just the other day. We'll see how it goes.

1 comment:

  1. Hank, are you able to say what this does for the Navy? I worked for the NSWC Carderock Div. for almost 7 years in the Electrical Machinery area, and I can't say I recognize where this is going to fit into the picture at all, certainly not at that sort of power level. More info on the application would be of great interest.