Monday, February 13, 2012

current status

New job is still kicking my ass, so progress on science crap is agonizingly slow, but non-zero!

I picked up some v-blocks (huzzah, Enco) recently which will allow me to hold the end caps of the triggered switch in the mill vise, using the same fixture I made to turn them in the lathe. That will let me make all the new holes (necessary for connecting other components to the switch, oops, durr, etc) with reasonably accurate and symmetrical locations, which is going to be important later. We're not talking thousandths of an inch precision, but more accuracy than I'd get with a lash-up in the drill press.

That task is actually sitting fixtured in the mill right now, ready to start aligning and laying out the bolt circle pattern with the DRO... just as soon as I have 3-phase power for the mill again. The burnt child fearing the flame, I have learned my lesson about solid state inverted AC motor drives, and I will be replacing the bricked one with an old fashioned rotary phase converter. Crude, slightly less convenient (an extra switch to throw to get started for the day) and slightly less perfect 3-phase power, BUT: it has the overweening quality of rock-of-Gibraltar reliability.

I priced good quality (this BTW the excludes the brand Phase-A-Matic, don't argue with me) equipment and got sticker shock. Relays are involved, and abuse is possible, so I'm somewhat reluctant to buy used, even from (as usual) a carefully vetted seller.
Further searches revealed a few small but reputable-looking bricks-n-mortar companies who have begun augmenting their motor repair / manufacturing / rewinding businesses by also offering rotary phase converters. Some of these outfits offer motor-less kits. That means they wire the complex parts (which weigh and cost much less than the idler motor), and ship same to you. You get your idler motor wherever, however, but the presumption is that if you live in a large metro area, you can probably find a used/surplus motor (must have good bearings) of disreputable cosmetic appearance, used, locally. Since 2HP motors are not light, you do not want to pay to have just one shipped across the country.

(Let the motor distributors do that more efficiently than you can by shipping a truck full at a time to your area.)

So that's the current plan, and a request for a quote has just been solicited. Given that a good quality 2HP - 3HP rotary, ready to go, is $500 or more, I'm expecting the quote without motor for a wired box to be somewhere around half that or less. We'll see.

And before anyone asks, yes, it would be possible, in theory, for me to build my own converter rig. But I would have to buy parts I don't have, at single-unit prices, and I DO NOT HAVE TIME. Ahem.

Oh, and I started taking a hard look at the necessary clamping forces to join two conductors carrying high (tens or possibly hundreds of kiloamps) connections, and realized that I'm going to have to rebuild the switch rather a lot, even before the first shot. This is depressing on the one hand, but on the other hand, I'm fairly certain that the switch would have disintegrated in dramatic and heart-breaking fashion had I attempted to operate it with the lousy connections it has now. Oh, er, I'm talking about the connections between the brass electrodes and the aluminum end-caps. I can still use those same electrodes with a modification to them, and I won't have to modify the end caps beyond enlarging the central bolt holes, and adding a small counter-bore on the inside of each end cap to accommodate an o-ring around the bolt. The mods to the electrodes will take about 8 hours, I'm guessing.

I really need the mill to be working, it's holding me up.

I finally ordered the replacement motor control board for the mill's power table feed, a feature I've been doing without since the mill came to me. The previous owner had been in the process of modifying the right end so as to be able to mount an aftermarket (ie; Servo brand, or a clone) table feed and toss the 1970s tech. I'd rather have a modern table feed, but this is loads cheaper so I'll be saving the modified parts for a rainy day, and putting the old parts back on, once I've repaired. That might not get finished until NEXT winter, because there's a lot of rework needed, and I won't really need it until I start on the electromagnetic launcher.

More as it happens.

PS: If I can get up to speed and performing well in this new job ASAP, and thereby preserve my employment with the company for the immediate future, life and hobby and science happiness will get better, because I will have more money and more free time in which to spend it. Fortunately, the nature of the job is such that for the parts when I have tests running, I can walk away for an hour or two to do other things. Lately, those things have mostly been domestic chores, but that will improve significantly as my wife continues to heal (she's doing great, BTW) from her left hip surgery. We're sorta hoping this will be the last one. :)

PPS: Red Lambda. We're going to take over the world of Big Data Security, not to mention grid computing in general -- you'll see!

(and props to anyone who recognizes that plagiarism)

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