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[PICS] Lay-wire TIG @ 200 amps and my VFD-upgraded drill press

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  • [PICS] Lay-wire TIG @ 200 amps and my VFD-upgraded drill press

    Here's some of my welding on S355 ordinary structural steel parts. 2.4 mm. 2% Thoriated electrode ground to a blunt point with a flat on the end, 2.4 mm. Lincoln LNT-25 (ER70S-3) wire, gas lens with ~12 LPM and #6 cup. пи40 mm. round stock with M16x2 partially threaded, 60x40x4 rectangular welded-seam steel tubing. This is before I gave the welds a light buffing, they cleaned up to a beautiful sheen and then etch-primered and painted with a brush. There was a slight gap at the broken corner of the round stock and a no-gap butt weld on the sides and on the bottom. The gold/copper marks might be from the ground clamp. I'm still having problems getting comfortable and getting a good view around corners, so the corners are not really up to snuff: overfilled and not properly wetted out. I also do TIG stainless and aluminium, and some stick welding.

    Here I'm fabricating a taller base with leveling feet for my old drill press I've been working on. It's old enough to be "Made in Norway". Never mind the two open holes above the switches of the drill press, I'm waiting on some gray plastic M20x1.5 block off plates and nuts. The switchgear is for FWD./Stop/REV. and accelerate/decelerate. And pay no attention to the rat's nest in the VFD control cabinet; it's not it's final form. I had to improvise full-wave bridge rectification and a filter capacitor to run a 12V DC 80 mm. computer cooling fan from a multi-tap door bell transformer. It's actually a trick setup: the VFD supplies 24V DC @ 100 mA. max for the control scheme. That voltage runs an NO contact on the black relay wired in series with the primary side of the aforementioned transformer. So when the fan's off, there's no humming or standby power draw from the cooling setup. It's programmed to the "RUN" state of the VFD and with 60 seconds off-delay, where the fan will keep running for a while after stopping the drill press. I did it the roundabout way because all the parts were free, just lying in boxes on my shelves, even the cabinet itself.

    But there's an even better way to do it with this Hitachi WJ200: it has a built in thermocouple on it's heat sink, and through programming you can run an external signal when the temperature reaches a user-defined set point. Can you tell I've read the manual? Also, I'm an electrician by trade, but specializing in new house construction, not the industrial side, unfortunately. As such, the VFD is over-sized for it's current load by a factor of 4 in case it'll power something else some day (2.2 kW VFD 230V 3~ in, "550 W" motor (weighing as much as a modern 3 kW one)).

    Yes, I'm also aware I'm in violation of the EU's EMC Directive 2004/108/EC by not having an input filter on the VFD; I might get 'round to it. I'm using fine-strand shielded cables and proper grounding and bonding, so I'm almost in compliance with the Norwegian NEC (NEK400:2014) at least. Just missing the point about "adhering to the manufacturers installation instructions", but enough about the codes already.







    Last edited by Oyvind Ryeng; 07-26-2015, 06:32 PM.

  • #2
    It looks pretty good to me.

    Your old drill press will be happy with it's new base.


    Dan
    At the end of the project, there is a profound difference between spare parts and left over parts.

    Location: SF East Bay.

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