Charting the S&P 500’s range-bound, but bullish, (unofficial) summer start | Lrd12 Overload Relay

One aspect of ac motor protection is the surge-withstand capability of the motor itself. Paragraph 20.36.4 of the NEMA motor generator standard MG-1 defines a unit value of surge as:   u × VL-L (or 0.816 × VL-L) where VL-L is the line-to-line voltage of the ac power system.

These were obviously mistakes. I would never intentionally come into contact with HT from the anode cap.

This is very dangerous. Safety regulations are all about keeping mains voltage away from people, inside casings that are earthed or double-insulated. This has the voltage just lying there. Possibly covered with a bit of silk-screened paint. It’s not guaranteed to kill someone, but for the extra money I’d sooner have a non-deadly heater for a 3D printer.

Yeah, I screwed up this one. I was looking for the ON State voltage drop, but they were giving the power, which I multiplied by the current giving the wrong value above.http://www.nxp.com/documents/data_sheet/BT137-600E.pdf this shows about 3-6W @ 5A. I was trying to compare both relay and triac at 5A, significantly below their rated max load. It looks like the affirmation still stands, the triac will dissipate more, but now the number is not even double.

Don’t blame the Chinese for this one! They are more than happy to sell us any quality we want. For example, you are probably reading this on a very well built, Chinese made, smart phone.

The nostalgia for “classic” miniature consoles isn’t ending anytime soon, either: Sony just announced today it’s making its own PlayStation Classic console. The tiny PS1 will come with “20 genre-defining titles,” and it’s set to release this December for $99.99. Also coming this winter is the Sega Mega Drive collection on the Nintendo Switch, and the trailer for it was published today.

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If it is a three phase installation then there are four wires run. These are three phases and the star centre point or neutral.

A couple months back I ran across a note in the datasheet for an inexpensive but reputably sourced power MOSFET that said that, while the die itself was rated for 200A continuous/400A peak the package and its leads were only rated for 125A/250A. So I said to myself “I wonder what the mode of failure looks like?” And built up a circuit to drive it to failure in a controlled manner. It was fairly spectacular: 1) the thermal expansion rate of the die doesn’t match that of the package and once you exceed some wattage tension builds up and (at least in the case of my particular DUT) the chip package literally exploded sending shards of epoxy and/or ceramic flying far and wide. 2) with the die now exposed in several areas and the connection to the heatsink thoroughly hosed by the explosion of the package things devolved rapidly and the magic blue smoke escapes (which smells very bad, FYI, and takes a while to fully purge that smell from the workshop).

I’d like to say that if a circuit breaker is X-degrees over ambient, it’s a problem… but there’s just no hard and fast rule for this. I can’t say this.

One of Sony’s nifty tricks is their in-camera "sweep panorama" technology. The A33 and A55 let you shoot panoramas with the camera held either vertically or horizontally. The vertical orientation makes taller/narrower panoramas that are 5,536 x 2,160 pixels, as seen in the top photo above. With the camera held in landscape orientation, panoramas are 8,192 x 1,856 pixels.

The farther I need to travel to get to you, the more time is taken out of my day—and I’ll factor that into your bill. Finding someone closer to your neighborhood might be able to charge you less.