4 ms·
Well, amateur experimental aircraft have something like this available: http://verticalpower.com/ http://verticalpower.com/ - but there's a lot of negative reac
by csirac2 12y ago
Well, amateur experimental aircraft have something like this available: http://verticalpower.com/ http://verticalpower.com/ - but there's a lot of negative reactions to this kind of technology, because it introduces new failure modes where none previously existed before.
But I think something that people forget is that generally, fuses are there to protect wiring and fixtures (switches, connectors, etc) from fire. Preventing the device on the circuit that you, the user, cares about from completely melting down is just a nice bonus.
That's why building wiring codes generally spec fuses to cope with the capacity handled by wiring and switches, rather than the loads attached to it.
EDIT: In any case you NEVER want the car to silently and automatically try to "re-set" a tripped breaker, surely. You want this kind of fault to present itself noisily and obviously; it's a precursor to a potentially dangerous condition.
Any automatic re-set will have to factor in some cool-down time for the wiring in between attempts... what is the temperature of an overheating pair of conductors in the wiring loom when the breaker tripped? What rate of heat dissipation is there allowing them to cool down again? A wire which has experienced overheating will have a different (higher) resistance after the short-circuit event. Even if the wire isn't permenantly damaged, the temporary increase in temperature will still guarantee a momentarily higher resistance. Will the wire still have low enough resistance to trip the breaker again when the short is applied again?
- arethuza 12y agoOn the point about building wiring codes, here in the UK we actually do have both central fuses/circuit-breakers and load specific fuses in the plug for each device. After reading your comment it did make me wonder as I plugged our coffee machine this morning how the design substantial chunk of plastic and metal I was holding was influenced by the aftermath of WW2.
- lmm 12y agoThe British plug is a marvel of good engineering. Other countries look on it with envy (except possibly Australia, which has a similar design of its own, IIRC). Now of course it was "overengineered" by the standards of the time, to compensate for our ludicrous, dangerous, and still-legally-required "ring main" system, which as you say was due to aftermath-of-WW2 copper shortages. But the plug design is the part we got right.
- robin_reala 12y agoAustralian plugs are good, but have the live pins at the top (so for example a dropped coin will balance across them and short when the plug is pulled out), the plug doesn’t have its own fuse and the socket isn’t shuttered with no plug inserted.
- csirac2 12y agoA few years ago they mandated the inner-most 5mm or so of the active pins be insulated for that reason, so that by the time you have enough of the plug out to reach exposed conductor with your fingers it's disconnected. At least that's idea... and I can't tell you how much ebay junk is sold with the old "illegal" exposed active pins
- robin_reala 12y agoTo be fair that wasn’t in the original design for the UK plugs either, sleeves were introduced in 1984.
- arethuza 12y agoSo Australian plugs are a bit like UK ones except upside down? :-)
- will_hughes 12y agoExcept the Australian plugs look like one of the masks from Scream or Scary Movie or something. Evidence: Socket: http://i.imgur.com/zwRYC25.jpg http://i.imgur.com/zwRYC25.jpg Mask: http://i.imgur.com/b0RAZ9k.jpg http://i.imgur.com/b0RAZ9k.jpg
- madink 12y agoI dare you to try to plug an australian plug in the dark. It's just impossible ! Most other plug make it way easier .
- agumonkey 12y ago