Motor Nameplate Current vs. NEC Full Load Current Values | National Electrical Code | 25 Amp Circuit Breaker

I think every power MOSFET in my box, most of them from reputable sources, have packages rated below the die.

Jamie Spinelli’s job as a case manager for Community Services Northwest takes her to parks, homeless shelters, the jail and…

I learned even more respect for shock hazards on the job one day when I was working for a military contractor. I forgot to turn off the 400VDC B+ supply to a radar driver assembly before I put one hand on the metal chassis and grabbed the fins of a lighthouse tube with the other hand. After that I put my head down on the workbench and had me a rest for a few minutes. Even when you know better, one moment of inattention can be the end.

Two inputs for the beefy converter are supplied from outlets not just on separate circuits, but on two circuits whose hot lines are 180 degrees out of phase. That means identifying where there are two plugs, not protected by GFCI outlets or breakers, which are on two separate hot lines of split phase power. To protect the user, [Nick] designed in a set of relays which kill the circuit when one of the two supplies is unplugged. A system that didn’t have these protections would have mains voltage on the prongs of the disconnected plug.

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The Residual Current Circuit Breaker is a tad expensive, and is probably overkill for most hobbyists. A Ground Fault Circuit Interrupter outlet, (GFCI), is cheaper to buy, cheaper to have installed, and a *knowledgeable* do-it-yourselfer can install his or her own. If you are knowledgeable about electrical wiring and codes, but don’t want to change an outlet in your house, you can buy a GFCI outlet and some regular outlets and make your own ground-fault-protected power bar, as a correctly wired GFCI outlet can protect additional regular (cheap) outlets as well. Alternatively, I’ve also seen GFCI units that plug in overtop of regular outlets and add protection to them.

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…

I guess writer JIM must be a “NEWBIE” or is otherwise mis-informed, but IEVs is continuing the FICTION that Underwriter’s Laboratories (UL) ‘CERTIFIES’ anything. He isn’t alone since every IEV writer says the same thing and its getting to be an echo chamber – but the end result is that IEVs is passing out bad information.

I suppose I would’ve used small contactors with auxiliary contacts as interlocking instead through some sort of arrangement, but that’s only because I have a pile of them lying around (and you would just put the wires under terminals rather than QD’s) but as I said (and you reinforced) I trusted your QD’s, particularly at these…”small” levels of current.

1) If not breathing, give CPR. Electrocution has pretty good recovery rates if CPR is started right away.

Step 1:  To find the voltage rating of the MOV, allow for 20% headroom to account for voltage swell and power-supply tolerances: 24 V dc × 1.2 = 28.8 V dc. Given that no varistors have a voltage rating of exactly 28.8 V, check the datasheets for specifications for 31-V dc MOVs.

Personally, I’m most excited about this for YouTube, since there’s never been a great, seamless way to make Sonos play audio from the leading video platform. Now you’ll just have to tap the AirPlay icon. There will likely be a bit of latency between sound and image with AirPlay 2, so it might not be ideal in all cases. But at least it’ll be a relatively easy option. Same goes for Netflix, HBO Now, and other apps that Sonos hasn’t previously supported on its end.