Things some idiot got wrong and now can't be put right

[bruce1530]

Hmm. When I moved into this house I noticed filament light bulbs had a very short life. Measured the mains supply and it was typically 251v, only just within the +10% limit ; is that the explanation for bulbs blowing? (asks the lapsed Electrical/Electronic Engineer!)

Yep. Particularly noticeable in the theatre world, where it’s not uncommon for 1000W lamps to have a rated lifetime of a couple of hundred (or even tens) of hours.

Dropping the voltage to 95% can double the lamp life, although dropping the output by about 20%.

In fact - if you google it, you find that the lamp life varies with the 12th power of voltage - so a tiny change in voltage makes a big difference to lamp life.

 

[classic33]

Will that stop the needle skating off them.

Black will render the copyright protection useless.

 

[cosmicbike]

Interesting thread, I design, but mostly build transformers and reactors for power transmission systems upto 330kV as well as isolated dc systems to 1,000,000V.

You soon gain healthy respect fot a test power supply that regularly breaks down over 32 inches of air with a nice fat lightning bolt and can induce a load of 40 tonnes over 1/50 of a second on the whole transformer structure..

I had a great experience at the Veiki-VNL lab in Hungary completing short circuit testing etc on new Tx designs. Admittedly only little ones, 2MVA 11kV, but to see one fail and physically move as the windings try and 'unwind' was amazing. Have to say their H&S was a little interesting..

 

[TVC]

I had a great experience at the Veiki-VNL lab in Hungary completing short circuit testing etc on new Tx designs. Admittedly only little ones, 2MVA 11kV, but to see one fail and physically move as the windings try and 'unwind' was amazing. Have to say their H&S was a little interesting..

Yep, every coil wants to act like a solenoid and fire itself off the core leg, people don't realise the huge mechanical forces in a distribution Tx just in normal operation. F=BIL

 

[Yellow Fang]

24 hours in a day? 60 minutes in an hour? 60 seconds in a minute?

Whatsalltharrabout?

I heard the base 60 numbering was Babylonian. It is a bit anomalous as everything else in the metric system goes up in powers of ten.

 

[classic33]

24 hours in a day? 60 minutes in an hour? 60 seconds in a minute?

Whatsalltharrabout?

https://www.myfavoritegadgets.info/other/MetricClock/MetricClock.html

 

[slowmotion]

I heard the base 60 numbering was Babylonian. It is a bit anomalous as everything else in the metric system goes up in powers of ten.

The pesky Babylonians pipped Gabriel Mouton to the post. By three thousand years.

 

[classic33]

I heard the base 60 numbering was Babylonian. It is a bit anomalous as everything else in the metric system goes up in powers of ten.

Imperial System goes up in twelves.

 

[slowmotion]

Hexadecimal anyone? Base 16.

It keeps almost the entire world of computing going. Gabriel Mouton must be rotating.

 

[swansonj]

Imperial System goes up in twelves.

Except when it's going up in eights, fourteens, sixteens, twenties, twenty-ones, twenty-fours,

 

[Dan B]

Hexadecimal anyone? Base 16.

Pounds and ounces, then

(Nitpicking, but computers are binary not base 16. Hex is just for human consumption)

 

[Tim Hall]

Except when it's going up in eights, fourteens, sixteens, twenties, twenty-ones, twenty-fours,

I've worked all of those out except twenty-ones. Unless there's a unit of measure based on playing pontoon.

Edit. Guineas, innit.

 

[Tanis8472]

You forgot 13

 

[subaqua]

Yep, every coil wants to act like a solenoid and fire itself off the core leg, people don't realise the huge mechanical forces in a distribution Tx just in normal operation. F=BIL

yet in Normal use very balanced.

Factory testing is good. one client needed 5 transformers but bought 6 as one was to be destroyed as part of the testing to find limits....

best day in work ever!

 

[swee'pea99]

Sort of akin to the thread title, I've always been intrigued by 'standards' that got set the way they did for perfectly good reasons, but remain long after those reasons have gone away, because they're integral parts of systems, whose operations are now hampered - for good. Two examples being the QWERTY keyboard and kitchen worksurfaces.

The former was designed the way it was to avoid typewriter keys locking together, and is probably now set in place for ever, since the other part of 'the system' - human operators - learns on it. (Attempts to introduce an alternative, the Dvorak keyboard, have proved unsuccessful, though "Because the Dvorak layout concentrates the vast majority of key strokes to the home [ie middle] row, the Dvorak layout uses about 63% of the finger motion required by QWERTY, which is claimed to make the keyboard more ergonomic.")

The latter was set at its current height to suit the American housewife of the '50s, meaning it's now several inches below optimum for most (now significantly taller) users, but will probably stay at that height from here on in, because the other part of 'the system' - the white goods designed to fit under it - have heights dictated by it.

In short, 'things' designed not by 'an idiot', but by perfectly sensible people for perfectly valid reasons, have bequeathed us systems which are inherently dysfunctional, and pretty much guaranteed to remain so.