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Anybody familiar with ECM, or Electro-Chemical Machining?

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ddmckee54:
I've got a couple of replacement bulbs for a stand mounted work light, they'd be about a KW's worth of load.  They were one of the ideas that I figured might get me nominated for a Darwin award, since they have such an unusual mounting base.  I've replaced the original fixtures with an LED work light from HF.  The heat from that KW worth of light would really heat up a small area, the LED runs MUCH cooler.

vtsteam:
Don, you have a 1 kW incandescent work light bulb? That's kind of amazing in itself! You don't have, or cannot get access to say, a 100 watt 120V light bulb?

Well no matter what 120V incandescent bulb you use, it won't be drawing its rated wattage at 36 volts. If you're worried about draw, and your supply isn't constant current capable, or over-current protected, you can always put a 10 amp fuse in line with the test rig.

Honestly, if you're really worried about getting a Darwin award when connecting a household light bulb as a test load to a 36 volt power supply, why are you DIYing an ECM? Just think, exposed metals, electrodes, electrolytes....etc.

ddmckee54:
I've got a work light that used a pair of 120V/500W Halogen rough duty bulbs, I think I've had that thing for 20 years at least.  The  bulbs are tiny little things actually, only about 10mm OD by 120mm long - with a contact clip on each end. 

I'm not worried about getting a Darwin award.  I really worry about what would my former engineering colleagues and electrician friends think when they read the story in the newspaper titled "Retired Electrical Engineer found electrocuted by light bulb?"

I'm not concerned about the ECM experiment, because it will be less dangerous than using a welder.  And I currently have 4 of those; a one-owner 50 year old Craftsman 200A AC/DC stick welder, an Eastwood 140A DC Mig, an Eastwood 140A DC Tig, and an Andrelli 140A AC/DC Tig.

vtsteam:
Well, sounds good, I took you at your word about worries! Also, halogen bulbs not what I think you should try for a load. I meant strictly incandescent tungsten every-day light bulbs. Or used to be "every day".

BTW I've run corded brush type 120V electric drills on un-regulated DC from a car alternator in the past. There used to be a little black box device you could buy in the '70's which just bypassed the regulator on a pickup truck, and the instructions said to run the engine idle up to the point where a neon bulb lit.

The bulb was wired to light over 100V. The box had an outlet, and a circuit breaker, the bulb and just some pioint to point wiring, but no circuit board or active components. Brush type 120V corded tools generally had what were called "universal  motors" which ran on DC as well as AC. In fact I copied the circuitry back then and made a generator from a horizontal shaft Briggs and Stratton motor and a car alternator, and it ran all kinds of power tools, including a circular saw, and a hedge trimmer.

Anyway, for those type motors, lower voltage DC will just run them slower, which was why I suggested it. Don't try to use them to do work at 36 volts, and you should be well under your 15 amp supply limit.

But again do nothing if you are in the least worried -- I write this not as a recommendation, just giving my own experience. There are dangers involved, yes, if one is inexperienced at this level of electrical DIY. Also be aware that DC is more dangerous than AC and 36 volts is above the threshold of possibly fatal consequences.

ddmckee54:
Yeah, it only takes a few mA under the wrong conditions. 

My 5mm ID supply tubing was finally found, order tracking said it was delivered on the 5th - but I couldn't find it.  I finally found the USPS tracking number and talked to the Post Office.  The mailman knew he'd delivered two packages that day.  We got to looking around and found it in a remote corner of the porch, under some wind blown leaves. 

The power supply seller and I finally agreed on a partial refund amount.  So I'll probably just put it into service, if it dies - it dies.

Now I need to kick the tires on my old Sunhokey 3D printer and see if there's any life left in it.  I think the last time I actually used it was pre-covid.

Don

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