Power Management, Chapter 8: Power Management ICs | 220v Contactor Relay

It is often a surprise to see how other people react to mains electricity when they encounter it in a piece of equipment. As engineers who have dealt with it both personally and professionally for many years it is easy to forget that not everyone has had that experience. On one hand we wince at those who dive in with no fear of the consequences, on the other we are constantly surprised at the number of people who treat any item with more than a few volts in it as though it was contaminated with radioactive anthrax and are scared to even think about opening it up.

A REAL Fotek is a good brand ….. however some dishonest shops in China are turning out fakes by the thousands ,,,,, I got burnt by a fake Fotek 25A DC SSR for a printer a couple of years ago and the 2nd or 3rd time I used it the MOSFET went up in smoke although nowhere near this spectacularly …. I ended up replacing it wtih a 100A Fotek that I could ascertain was genuine and it’s been working ever since

Also, when you say “..10A relay will dissipate maximum 2.5W through the 0.1ohm contacts…” also does not seem to be correct: P=R*I^2, so @10A it’s 10W

Point taken. Perhaps it’s time to change of the the mindset, of the at large DIY community to when treated with properly 120/240 VAC can be used safely, as it’s being used day in and say out. I recall a project of Limor Fried made a project more as need be be becase she appered to be overly frearful of line voltage, then again she was taking into consideration the carelessness in the hacker community. One the flip side I personally know electrical engineers with decade in the filed who flippantly say 120 VAC can’t kill you. I know enough to know they are being full of shit In the end because of irritation fear useful resource is being ignored. Then again I have history of being comfortable with working on motor controls with neatly 800 VAC feeding them or working with electronic devices that have more than 30,0000 volts inside the cabinet. Lower voltages bring greater safy to life burt rquire higher current to do the amount of work, potetiall a fire hazrds id something goes wrong.

Look and feel. Although it lacks the reflex mirror of an SLR, having replaced it with a fixed translucent mirror, the basic shape of the Sony SLT-A33 still follows that of a traditional SLR fairly closely. That’s because, since it accepts the same Alpha lenses as Sony’s DSLRs, the Sony A33 also has to accommodate the same backfocus distance, which is one of the main contributors to the size — and especially, the depth — of an SLR camera. Removing the reflex mirror still provides potential for space and weight savings, and Sony has taken good advantage of this. Most obviously, the drive mechanism that raises and lowers the reflex mirror in a traditional SLR isn’t needed. The translucent mirror design also provides other opportunities to optimize component placement. As one example of this, Sony has increased the angle of the translucent mirror, so that instead of directing light directly upward at a 90 degree angle as it would for a viewfinder prism, it is actually angled upward and slightly forward, allowing the autofocus sensor to be moved forward, providing more room for the electronic viewfinder assembly directly to the rear.

Where I do agree that it is under rated, as far as I know, Mathias is an electrical engineer. So he should be able to work with mains, and he should also know better.

2. It’s very likely that this device will need to be used with extension cords in order to find two GFCI-free outlets in different phases. That, fundamentally, is why this project is – generally speaking – a bad idea. Still, extension cords can be used safely if you don’t draw too much current through them. The use notes in the article speak to the need to derate circuits appropriately. But that said, the derating doesn’t change just because you pull 240V instead of 120V.

While the Sony A55 and A33′s singular claim to fame is its exceptional shooting speed, that’s only part of what it has to offer. Just in the last year, Sony has used its high-speed sensor technology to create a number of innovative new camera features that, on their face, have nothing to do with high-speed shooting. This hands-on report is already running far too long, so I’ll just make brief mention of some of these special Sony modes here. Even if you feel no need for 7 to 10 fps capture in your personal shooting, these special exposure modes alone would be reason enough to buy one of these cameras.

Solar water heaters are nice. Sadly, when one gets far north, the sun isn’t a common sight during the cold parts of the year.

The crimp terminals I am using are rated for 24A, and I am using a ratcheting crimping tool. I have checked, and therefore I do not believe you.

Yup, switched off but still plugged in, that way the case is still earthed. Assuming a sensible 3-pin plug, or whatever the hell they do in places with just 2.

Teslas are a special exception since the S, X and Roadster all took a 30% hit to efficiency when charging at 110 and really needed 190-240 to charge efficiently. Other brands like GM or Ford or Toyota seem to charge relatively efficiently at 110.