USA could also transition to a proper mains voltage like much of the rest of the planet.
But 50 Hz as a system frequency is just wrong. It results in oddities like running your railroad at 16-2/3 Hz.
(I guess you are talking about three-phase power in general, or is there anything special about railroads?)
In practice, just like everything in engineering, you don't run your grid at 50 Hz nor your railroad at 50/3 Hz. You run the grid at some frequency that varies slightly around 50Hz. There's always engineering tolerances.
So even if you don't like rational numbers, it doesn't really matter whether you run the railroads at 50/3 +-0.01 Hz, or at 16.66 +-0.01 Hz.
(I don't know how tight the tolerances are in practice here. It doesn't matter for the argument.)
Also, 60 is a common base for several things (degrees, time), which interact with the grid in numerous ways.
It’s convenient to have them match.
(If you need more precision, go for nano-Hertz..)
> So even if you don't like rational numbers, it doesn't really matter whether you run the railroads at 50/3 +-0.01 Hz, or at 16.66 +-0.01 Hz.
In practice the nominal frequency was changed to 16.7 Hz anyway due to some weird edge case created when running motor-generators [1] for prolonged periods of time at exactly the nominal 3:1 frequency conversion ratio. (See https://de.wikipedia.org/wiki/Bahnstrom#16_2%E2%81%843_Hz_ge... and use an online translator at your own peril if necessary.)
[1] These days, newly built (or probably occasionally re-built) substations prefer to use solid-state frequency converters, which are immune to this particular problem, but there still are enough of the older motor-generator sets around, too. Wikipedia also claims that motor-generator sets are more tolerant against earth faults, which might or might not preclude against getting rid of all of them even long-term.
50 Hz railway systems are probably more common than 50/3, at least in Europe:
https://en.wikipedia.org/wiki/Railway_electrification_system...
25 kV AC 50 Hz (60 Hz in countries using such grid frequency) is the modern standard: https://en.wikipedia.org/wiki/25_kV_AC_railway_electrificati...
A classic commutated series-wound motor is a DC machine. The problem with DC power is that without power electronics, you can't really change the voltage (except downwards by wasteful resistors), so your transmission voltage is limited by your maximum motor voltage and you incur relatively high transmission losses and need frequent substations every few kilometres. (Mainline railways can cheat a bit by equipping all of their rolling stock with two (or occasionally more) motors permanently linked together in series, so each motor only gets a fraction of the voltage, but you can take that approach only so far…)
So you want to switch to AC power, which is more efficient because it can be easily transformed up and then down again, because transformers can actually be made small enough to fit into a locomotive.
Fortunately with some adaptations a series-wound motor can be made to work on AC, too, but there are some trade-offs depending on the required amount of power and the frequency. I.e. the motor still works better if your AC current is more "DC-like", i.e. doesn't have too high a frequency.
It turns out that for something more modest like a hoover or a domestic power drill, an AC series-wound motor ("universal motor") will work fine enough even at 50 or 60 Hz, but for railway purposes with their somewhat higher power demands things didn't work so well.
Because at that time power electronics didn't exist or were still in their infancy (e.g. mercury arc rectifiers), there was no possibility of doing anything useful on board of the locomotive, so instead it was decided to reduce the frequency of the railway's power supply system, because at 16 2/3 or perhaps even 25 Hz motors could still be made to work reasonably enough.
Also at that time changing the frequency meant using a motor-generator set, and presumably choosing some simple integer ratio for the two frequencies also simplified things.
By the time other countries started considering switching to AC electrification, usable rectifiers existed that could be used on locomotives, so those countries could electrify at the full 50 or 60 Hz and then rectify the current to DC on board of the locomotive, thereby sidestepping the problems of running a commutated series-wound motor with AC power.
Even later on we then got fully variable voltage and frequency inverters, which finally allowed serious usage of (usually asynchronous) three-phase induction motors.
(Some railways used three-phase drives even before that, but without modern electronics this was a somewhat more cumbersome prospect, see e.g. https://en.wikipedia.org/wiki/K%C3%A1lm%C3%A1n_Kand%C3%B3)
The heavy load stuff is 240V anyway.
The British plug is a pretty decent design from an electrical safety point of view. (However, they turn into caltrops in the dark.)
It's needlessly huge. I like type J (SN 441011, Swiss plug) and type N (IEC 60906-1, South Africa).
It's just that the American plugs are really the worst. See also https://www.youtube.com/watch?v=K_q-xnYRugQ for other badness.
208V (vs 220/230/240V) has minimal to do with it being a condo and everything to do with the type of incoming power. 208V is from taking two phases of a 120V three phase service. One phase to ground, 120V, phase to phase, 208V. For the alternative voltage (named 220/230/240V depending on context), the incoming power to the transfer is a single phase. The transformer then produces a split phase 220/230/240V where each phase is 180° opposite each other. The only reason you _might_ see it more frequently at a condo/apartment is due to there being a need or desire for 3 phase power.
Where it gets a little funny is that the Canadian standard for "industrial" power is 600V, not 480V, and that can make it hard to find replacements in some larger buildings with custom requirements.
Yeah, didn’t mean to imply it was unusual, just explaining for others that it’s not a quirk of condos/apartments specifically.
> Where it gets a little funny is that the Canadian standard for "industrial" power is 600V, not 480V
Speaking of 480V, you ever dealt with 277V much? That’s a real “fun” voltage to be around when something goes wrong. :(
My condo parking spot has a wonderful looking junction box above it labelled “600V”.
But I’ve heard some Canadian factories will still get spec’d with “US Voltage” (ie: 277 and 480) for “standardization”, but probably so they can move the plant to the US without having to find electricians that can speak Canadian.
Yeah, if you don’t have 480V, extremely unlikely you’ll have 277V. 347V has comparable issues to what I was referring to with 277. 480/600 aren’t voltage you’ll normally find wire nut’s in a jbox or behind say a light switch for example, but 277/347 you will. Unlike 120V though, if something were to cause it to arc (or worse, electrocute you), you’re going to have a very bad day! Not tagging off a circuit is always a bad idea, but especially when voltages are 250+.
The 120V in the US is a 640kb ram should be enough situation. You were first, thought you build the spare capacity, were surprised by the explosive growth and how useful electricity really is.
With modern homes moving to 100% electricity even 240 is not enough. In my flat I have pizza oven (3kw),inducation burner x 2 (3kw each), normal oven, 12000 btu AC x 2, tumble dryer, some other appliances that chug sub 1k... throw in some car charging, electrical water heater... A modern home is using orders of magnitude more electricity. And it is going up.
2 base 2 orders of magnitude perhaps, but not 100x more…
As homes need more power, they are delivered more amps. The common for newer construction in the US is 240V at 200 amp or 400 amp for larger homes. Older homes will have anywhere from 80-150A depending on when they were built or remodeled enough to require replacing the main service panel.
Stove, HVAC, and dryer require their own dedicated 240V circuits.
In eu you don't have to think where to plug 2.5 kw space heater. Any outlet is good enough. In the US you have to. And with home appliances actually becoming bigger and more powerful I think that even the EU baseline will become too constraining eventually. Since usually there are limitation on the gauges that are ran from the main breaker to the sub-breakers (don't know english electric jargon)
Where I live I have a wire that can hold I think 40 amps in the wall from the main breaker to the board where the small breakers terminate the different home circuts. If I want to upgrade it is dig baby dig. 6 floors.
https://www.youtube.com/watch?v=jMmUoZh3Hq4&ab_channel=Techn...
Basically, you'd express things in terms of speed of light, electron charge, planck length etc.
In this case, [Planck energy / electron charge] might be an appropriate unit.
(It would also be a pretty useless unit, because it's absurdly large compared to everyday voltages.)