Why do circuit breakers go up for on and down for off?

Feb 11, 2023 Last reply: 2 years ago 1839 Replies

Completely impractical if the danger is hidden until you get there. Children and animals dashing across the road. wheel smashing potholes full of water that the council can't afford to fix because they spent the budget on speed cameras sleeping policemen and totally unnecessary traffic lights. Old truck brake drums dropped from pedestrian bridges by bored teenagers.

The list of 'stuff that you can hit that wasn't there last time you looked' is endless.

Maintaining idealised safe distances is an idea only people who don't really do much driving believe in.

Pointless as modern power supplies can easily accommodate wide ranges of voltage. They should have left it up to manufacturers to decide what range of voltage to cope with, depending on where they wanted to sell the goods. 100-250V (50/60Hz) for Europe and US, 200-250V for UK and Europe, 220-250V for UK only. Some goods are/were only suitable for the UK due to language and TV system.

Euroharmonising for the sake of it.

? I think there were springs on the driving wheels actually. Really big locos were more the province of the USA with its enormously long straight tracks

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shows that driving wheels are sprung, though possibly not independently.

In practice the railroads were built to run steam trains with up to 8 close spaced driving wheels, and if that made life difficult, tough.

The big 8 wheelers were more suited to the USA with bigger steeper inclines but seldom tight curves.

Also for use in more cramped conditions twin sets of drive wheels and cylinders could be used.

Curiously, others than yourself thought about this at the time

How do you know it wasn't accommodated within the acceptable tolerance for mains voltage? 230 is just "nominal".

Same here. The stated voltage just changed.

Yes, it has been my experience that the Spanish even in S America prefer to build with concrete or blocks as the high thermal mass is useful in reducing peak temperatures by day.

Whereas the USA is the home of the timber frame as long as its got air con :-)

It is quite hard in the UK to get a mortgage on a 100% timber frame.

Yup. I built several of those on 27Mhz for model planes. Not with valves though.

Old mains radios had a switch at the back to set the voltage. Easier with AC than DC as it just switched the tap on the mains transformer. For DC there was a dropper resistor. If it had to work on 120V AC/DC the set was designed for the lower voltage and had to dissipate the extra power in a resistor, often built into the mains lead.

Ok, I see them. I will have to look more carefully at others.

Just barely for the old bulbs. 230 would be OK, but the new margins meant the voltage could go to 240, and that was not OK for appliances. Slowly, eventually, we had to replace everything. But not possible to claim that they failed sooner for overvoltage.

Not for the sake of it.

I have been able to buy UK appliances via Amazon to use here, knowing that they would work fine.

>

In that case, I won't be able to hit the blinkers, either.

Tell that to the regulators.

Cartagena.

Nope.

+1. A more useless bit of virtue signalling 'harmonisation' the EU has yet to dream up.

If manufacturers want to cope with different voltages and frequencies they can. Or not, if they dont.

I am fairly sure that one of my guitar amplifiers has an SMPSU that can cope from 110V AC or DC to 240VAC or DC.

I haven't read the replies.... So you can't turn them on by accident?

We never lost them. In most places, the usual voltage is still around

240V. Without painstakingly checking the latest spec, the official UK tolerance is 230V +10%/-6%, and the European is 230V +10%/-10%. [You do the maths!] In my home, it's usually between 236 and 240V.

That depends on the transmission frequency wavelength; e.g. if the antenna was shorted from 1/2 wave to 1/4 wave, it will likely not substantially change the transmission range (depending on the frequency).

That would explain the Soviet style apartment blocks I see in British films. Some attempt to dress up the poured concrete construction with limited success. Almost all new construction in this area is platform framed wood construction, sheathed with OSB, wrapped in Tyvek, and some sort of decorative siding applied. The exception is multistory commercial buildings.

Indeed. From Audel's volume 1:

"Horse Power - This unit was introduced by James Watt to measure the power of his steam engines; defined as 33,000 ft. lbs. per minute." Audels Engineers and Mechanics Guide Vol 1. pg 78.

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The first two volumes are a fascinating introduction into the theory and mechanics of steam engines.

My favorite (At the California Railway Museum in Sacramento):

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It's much larger than it appears in the picture (look for the placcard holders alongside for a sense of scale).

The cab was forward of the stack to avoid suffocating the drivers in the long sierra tunnels.

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