VLC is blacklisting recent Huawei devices to combat negative app reviews | 220v Contactor Relay

Theres a homebrew 80vdc @150amp supply in my cnc converted bridgeport, that runs the entire dc rail for the steppers and other stuff, its always scared me slightly because I know that the big transformer its based on has a mag field and when it collapses and it has some massive smoothing capacitors to boot, so I have masses of isolation distance everywhere the dc side runs and I disable the transformer with a dedicated switch while working in the cabinet of it. I had a stepper driver supplied directly off the rail go bad and it just had a large hole where it used to be. I just imagine that was a bit of me if I get tempted to get sloppy with it. I’ve never put much thought into getting electrocuted by a welder, I’ve tickled my finger with my 3 phase tig set more than a few times getting too close and giving a nice easy starting path to the startup pulse. Maybe I should, I’ve got a massive 3 phase 380v transformer tig that can do 375amp dc, that tends to throw all the breakers out while its saturating its massive transformer with the inrush current… I try to treat mains voltage with the respsect it deserves. Its a killer, but if you take sensible precautions and steps you can avoid it being you it happens to.

You are right, FR-4 has a glass transition temperature of around 120°C, so if you heat up your traces above that, and take into account the mechanical stress from expanding copper traces, delamination is something waiting to happen sooner or later (especially if you design corners in your traces). Add to that the fact that you usually don’t measure the temperature directly on the traces to regulate input power, you could go way beyond 120°C in your copper traces. I don’t think a lot of DIY guys actually know that there would be high-TG materials on the market better suited for PCB based heater applications…

“To get 120 watts at 12 volts requires thick wires that can handle 10 amps, whereas at 120V, tiny 1A wires will do”.

Relay was severely underrated for the application. Also the real moral of the story is that when you use a ten dollar relay, you get ten dollar performance.

For something like this I would go to a proper electrical supplier and probably would use an AC contactor relay that’s rated twice the current. Sure a contactor needs a 24V transformer but it’s a small price to pay and the current use would be insignificant compared the the hot water heater.

Of course in this case, there’s less heat per length of track, but the tracks are longer. So it cancels itself out in the end.

well, originally they were 2 kW transformers (or at least from microwaves that are rated to 2-2.5 kW), and on secondary is wounder stranded thick wire (diametar around 7-8mm)… enought power to melt nails with 3-4 mm diametar…

Video capture is an area where the Sony A33′s translucent mirror technology makes a huge difference relative to pretty any other SLR currently on the market, and relative to even fast-focusing SLDs. Every other interchangeable-lens camera currently on the market either doesn’t autofocus at all when recording videos, or has to resort to slower and/or more obtrusive contrast-detect focusing. Because the Sony A33′s phase-detect AF system is always looking at the subject, fast autofocus during video recording is no problem.

i built the rig that day. I put an ammeter with max hold on a circuit, plugged the circuit into a known 20 amp connection, and put a load on the circuit that simulated the instrument. Turn it on, 22 amps max hold, 13 amps nominal.

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If he ever turns his car on its side so that the car jack is pointed toward ceiling and plugged into the evse as shown, then I’d worry about it.

When I was doing rehab work on old Chicago apartments I would often find electric wires run through abandoned gas lighting pipes, ready made conduit going to where the old gas light fixtures were, not exactly code and very confusing, especially since there were “live” gas pipes mixed up in the walls and ceilings with the ones carrying Mr. 120!