[HN Gopher] The origins of 60-Hz as a power frequency
___________________________________________________________________
The origins of 60-Hz as a power frequency
Author : theamk
Score : 110 points
Date : 2025-02-07 16:53 UTC (6 hours ago)
(HTM) web link (ieeexplore.ieee.org)
(TXT) w3m dump (ieeexplore.ieee.org)
| ethbr1 wrote:
| If only we could tag thought threads for submissions. Funny to
| see this coming out of the Baltic disconnect comment section!
| timcobb wrote:
| Thought threads?
| ethbr1 wrote:
| https://news.ycombinator.com/item?id=42973958
| antithesis-nl wrote:
| (1997), which I wondered about due to the "Many people continue
| to be affected by the decisions on frequency standards made so
| very long ago" phrasing and the intro-bit about the need for
| adapters in the paper itself.
|
| Because these days, voltage and especially frequency are pretty
| much irrelevant for mains-power AC, and "ignorant" will be more
| accurate than "affected" when it comes to "many people"...
| bluGill wrote:
| They don't know it but they likely have a motor someplace in
| their house that runs at the speed it does because of
| frequency. They are ignorant but it affects them.
| theamk wrote:
| It is less and less likely... motor-based clocks are a thing
| of the past; hand appliances (like mixers and blenders) use
| either DC or universal motors to allow speed control. Even
| refrigerators feature "variable speed motors" nowadays, which
| means they are frequency-independent.
|
| I think fans will likely be the last devices which care about
| frequency.. but new ones are often 12V/24V-based, with a
| little step-down modules.
| satiric wrote:
| What about dryer motors? I mean, I don't much care what rpm
| the dryer runs at, but it should change speed with the grid
| frequency right?
| kencausey wrote:
| I wonder if resistive heating devices like ovens which
| have a tuned temperature component would become
| systematically less accurate if the frequency changed
| significantly.
| smallmancontrov wrote:
| Nah, the thermal time constant is a low-pass filter on
| the order of .01Hz, all of the line frequencies in this
| thread are waaaay higher than the control loop bandwidth.
| The loop would never notice the substitution.
|
| You might be able to trip up a fancy soldering iron where
| loop bandwidth is intentionally maximized, but I still
| suspect the first thing to go would be the magnetics on
| anything with a transformer.
| exmadscientist wrote:
| > first thing to go would be the magnetics
|
| Yes, but not for the reason you'd think: 50 Hz magnetics
| have to be physically larger to work (peak flux density
| for a given current is higher), and magnetics are so big
| and heavy that they're not designed with much margin. So
| 60 Hz transformers will often not work at all at 50 Hz,
| and 50 Hz transformers will sometimes perform pretty
| badly at 60 Hz (though also sometimes going this
| direction works fine).
| bluGill wrote:
| Modern dryiers are generaly run on a phase converter so
| while the motor is ac the frequency is controlled by a
| computer.
| quickthrowman wrote:
| Most commercial AC fan and pump motors are already powered
| by variable frequency drives, and a lot of newer
| residential appliances have EC motors to allow for speed
| control.
|
| I'm seeing more and more EC motors in commercial
| applications, for things like 2-3 HP fam motors and pumps.
| bluGill wrote:
| Fans because a furnace only needs two speeds at most.
| creeble wrote:
| True for consumers (houses), not true for industrial
| applications where motors are in the >100HP range.
| rkagerer wrote:
| Link straight to PDF:
| https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=628...
| ethbr1 wrote:
| Tl;dr - Because Westinghouse (60 Hz) beat out GE (50 Hz) in the
| early (~1910+) American AC electrical equipment market.
| SigmundA wrote:
| My Tl;dr would be a little longer - early systems used both
| higher (around 130 hz) which caused issues with resonance and
| difficulties making induction motors, and lower (around 30hz)
| which caused light flicker.
|
| 50-60 hz solved these issues, Westinghouse thought 60hz was
| better for light flicker and beat out GE who settled on the
| 50hz standard used by it's European affiliate that moved up
| from 40hz due to flicker.
| cf100clunk wrote:
| 25hz too, mentioned in another thread.
| SigmundA wrote:
| 25hz is part of the "around 30hz" I mentioned. It was a
| compromise for the Niagra falls turbines between 16.7hz
| which was good for large motors at the time and flickering
| lights for which Westinghouse wanted at least 33.3hz.
| Analemma_ wrote:
| In Seattle you can take a tour of the Georgetown Steam Plant,
| which was an early power station. At one point they mention
| that the plant had two totally separate generators at
| different frequencies: one for household mains power and one
| for the electric streetcars.
| MBCook wrote:
| But that TLDR doesn't answer why those companies chose those
| frequencies.
| Ericson2314 wrote:
| https://en.wikipedia.org/wiki/Amtrak%27s_25_Hz_traction_powe...
| predates standardized 60 Hz, and still hasn't been converted (!!)
| _trampeltier wrote:
| Switzerland trains still use 16,7 Hz (16 2/3Hz)
| Ericson2314 wrote:
| Yes indeed, but the German-Swiss-Austrian 16.7 Hz system is
| many orders of magnitude bigger than the Southend
| Electrification! The path dependency is much more
| understandable in that case.
| 486sx33 wrote:
| Ontario, Canada, at niagara falls generated 25hz for industry
| (stelco and others) until the early 2000s
| https://www.lifebynumbers.ca/history/the-rise-and-fall-of-25...
| alex_young wrote:
| 60 Hz sure makes it easy to keep clocks on time.
| hatsunearu wrote:
| 1/60th of a second isn't a common unit of time though
| toast0 wrote:
| It's convenient to count 60 pulses to make a seconds pulse,
| then 60 of those to make a minute pulse, then 60 of those to
| make an hour pulse. Then 60 of those to make 2 and a half
| days :P
| theamk wrote:
| As far as clocks are concerned, 60 Hz or 50 Hz are very
| similar, just make sure the number of teeth on gears match the
| frequency.
| ThisNameIsTaken wrote:
| Not sure it's precise enough though. In 2018, many clocks in
| Europe were off because the frequency on the net had drifted
| due to (as I understood it) the network being out of sync
| across various countries. Some here might actually understand
| the details of this.
| wongarsu wrote:
| The frequency drifts up and down whenever demand doesn't
| exactly match supply. Higher demand slows the frequency down,
| higher supply speeds it up. This is actually the main way
| power companies know if supply and demand match, and if power
| stations have to ramp up or down.
|
| The frequency changes are pretty small in normal operation,
| but on a clock that uses the frequency to keep time they
| accumulate. They only work reliably because power companies
| know about them and occasionally deliberately run a bit over
| or under capacity to make the average match again.
| kps wrote:
| In 2018 the European grid lost a cumulative 6 minutes due
| to a Serbia/Kosovo dispute.
| andlier wrote:
| Fun fact, there are databases of the exact frequency vs.
| time and it can be used to accurately time stamp
| audio/video recordings by correlating the ~50/60hz noise in
| the recording with the database. Good writeup on the
| technique and how it has been used in court cases:
| https://robertheaton.com/enf/
| folli wrote:
| This is fascinating, didn't know. Why does higher demand
| lower the frequency?
| creeble wrote:
| Because generators -- where virtually _all_ AC power is
| created -- start running slower with high demand. They
| catch up, via increased power input through governors,
| but changes in load will necessarily have some impact on
| speed.
| duskwuff wrote:
| The frequency is generated by rotating electrical
| generators. Higher electrical demand increases the
| mechanical load on the generator, making it rotate more
| slowly, producing a lower frequency.
| bonzini wrote:
| With a lot of simplification, consuming electricity acts
| as a brake on giant wheels inside the power plants that
| are usually spinning at mains frequency. The plants
| accelerate the same wheels, so with much demand the
| braking wins and with too little the acceleration wins.
| nottorp wrote:
| I don't think 60 or 50 Hz matters wrt to this.
|
| The only thing that matters is that a clock that expects a
| certain frequency gets that frequency and not 1% more or 1%
| less.
| mystified5016 wrote:
| In the US, we modulate (or used to) grid frequency
| specifically for these analog clocks such that in a 24hr
| period it averages to exactly 60Hz.
|
| It doesn't really matter on a second-to-second timescale how
| accurate grid frequency is. If you can keep the _average_
| frequency right, all your clocks will speed up and slow down
| in sync, and average out to 24hours per day
| nom wrote:
| think again
| UltraSane wrote:
| Fun fact: Japan uses BOTH 60Hz and 50Hz for mains electricity due
| to historical generator purchases. This means the Japanese
| electric grid is split into two regions that cannot easily share
| electricity.
| _trampeltier wrote:
| The US alone has 3 grids (East, West and Texas). With the same
| frequency but still not connected.
|
| In Switzerland trains use 16.7Hz but they are connected with
| large frequency inverters. Before it was with large motors /
| generators. Now its just static with electronic.
| trothamel wrote:
| The same frequency, but not connected via AC. There are
| multiple DC and Variable Frequency Transformer ties between
| the various interconnections.
|
| https://en.wikipedia.org/wiki/North_American_power_transmiss.
| ..
| cf100clunk wrote:
| Exactly, DC is used for those links that would otherwise be
| out of synchronization. In Canada one of the DC links goes
| from the North American grid on the British Columbia Lower
| Mainland in Delta via a single underwater cable over to
| Vancouver Island. The water is the other conductor, and
| also keeps the cable cool.
| Aloha wrote:
| We have more than three interconnections that are not in
| synchronous connection to each other.
|
| They can share power and are somewhat connected with HVDC
| interconnections however.
| viraptor wrote:
| Same with mainland Australia and Tasmania with HVDC cable
| going through the sea.
| fyrn_ wrote:
| This is covered in some detail in this paper? They even discuss
| the two engineers who made the purchase and who manufactured
| the generators..
| themaninthedark wrote:
| I want to say this was part of the issue after the Tohoku
| Earthquake, my recollection was that some generators got
| brought in to support the ones that were flooded but were
| incompatible. However, I can not find any note of it in the
| timelines and after-action reports that showed up when I
| searched.
|
| So possibly misremembering or fog of war reporting, or perhaps
| not important enough for the summaries.
| voxadam wrote:
| (1997)
| 1-6 wrote:
| Duodecimal Society members are happy.
| pkulak wrote:
| I always assumed it's because 60 is a highly composite number
| (superior, in fact!). It's kinda the best number if you're ever
| going to need to divide. 50 is kinda garbage in that regard. :/
| beeflet wrote:
| It's worth mentioning 60Hz vs 50Hz distinction has ended up
| having a knock-on effect on framerate standards because of
| early TVs using it for timing, not to mention market
| segmentation because different products had to be manufactured
| for the US vs European markets.
|
| here is a well animated video about it:
| https://www.youtube.com/watch?v=DyqjTZHRdRs&t=49s
| makerdiety wrote:
| The number sixty is highly composite maybe because it's a
| multiple of three? In which case, I can see why Nikola Tesla
| liked the number three or multiples of three.
|
| So he can do exploratory electrical science and analysis with
| flexible cases?
| PortiaBerries wrote:
| Yes! I was looking for this comment. Maybe because I didn't
| grow up with the metric system, but 60 feels like a much
| "rounder" number to me than 50.
| layer8 wrote:
| Well, 50 Hz means the period is a round 20 ms instead of
| 16.6666... ms.
|
| And PAL got a higher resolution thanks to it.
| freeqaz wrote:
| If we could magically pick a frequency and voltage for electrical
| systems to use (without sunk costs), what would it be?
|
| What's the most efficient for modern grids and electronics?
|
| Would it be a higher frequency (1000hz)?
|
| I know higher voltage systems are more dangerous but make it
| easier to transmit more power (toaster ovens in the EU are better
| because of 240v). I'm curious if we would pick a different
| voltage too and just have better/safer outlets.
| IncreasePosts wrote:
| I don't care what the frequency is, I just want my LEDs to not
| flicker!
| xanderlewis wrote:
| What about if they flickered at 10^-15Hz?
| viraptor wrote:
| That would be really annoying to tell if they're broken, or
| just currently in the "off" phase :)
| sxp wrote:
| Normal LED lightbulbs shouldn't flicker on standard 60Hz
| circuits. Do you have a dimmer switch or smart switch in the
| circuit? I've noticed these cause flickering that's visible
| on camera or out of the side of my eyes.
| SSLy wrote:
| that means that either the breaker is faulty, or the power
| stabilizator in the lamp itself is junk.
| lnsru wrote:
| Get better ones. I installed expensive LED lamps at home and
| they're fine. The guys in the office picked the cheapest ones
| and I don't want to turn these ugly things on.
|
| Edit: Paulmann Velora are the expensive lamps at home.
| homebrewer wrote:
| https://lamptest.ru tests for flicker too. I don't know if
| those models are sold in the US, though. Philips, Osram and
| IKEA should be.
| xanderlewis wrote:
| Why are toasters better at 240V? Can't you just pull more
| current if you're only at 120V (or whatever it is in the US)
| and get the same power?
|
| I guess there's some internal resistance or something, but...
| mypgovroom wrote:
| You have a 240v toaster?
| xanderlewis wrote:
| Well, closer to 230.
| qayxc wrote:
| _goes to check real quick_ between 238V and 245V at my
| outlets.
| stuaxo wrote:
| Living in an a country with 240v mains, yep.
| bbatha wrote:
| More current needs thicker wires. The average US outlet is
| wired for 120v15amp. 20 amp circuits are somewhat common,
| though 20amp receptacles are not. Certainly not enough for
| commodity appliances to rely on.
|
| Going to more than 20amp requires a multiphase circuit which
| are much more expensive and the plugs are unwieldy and not
| designed to be plugged and unplugged frequently.
| generallee5686 wrote:
| Having more current running through a wire means thicker
| wires. Higher voltage means less current to achieve the same
| power, so thinner wires for the same power. The tradeoff for
| higher voltage is it's more dangerous (higher chance of
| arcing etc).
| wongarsu wrote:
| Houses are wired for 16A per circuit on both sides of the
| pond, with high-power appliances typically pulling around 10A
| to avoid tripping the fuse when something else is turned on
| at the same time. It's just a nice point where wires are easy
| to handle, plugs are compact, and everything is relatively
| cheap.
|
| The US could have toasters and hair dryers that work as well
| as European ones if everything was wired for 32A, but you
| only do that for porch heaters or electric vehicle chargers.
| mystified5016 wrote:
| No, the standard in the US is 15 or 20A. 20 is more popular
| nowadays.
|
| 240V appliances typically get a 35 or 50A circuit.
|
| But then you also have to deal with the fact that a _lot_
| of homes have wiring that can only handle 10A, but someone
| has replaced the glass fuse with a 20A breaker. Fun stuff.
| bardak wrote:
| I still haven't seen a single 20A domestic appliance
| though
| tgsovlerkhgsel wrote:
| You need the same thickness of wire for 10A regardless of
| which voltage you have. So with 230V, your 10A wire will let
| you draw 2.3 kW while someone with 120V and 15A wire would
| only get 1.8 kW _and_ pay more for the wiring.
| andruby wrote:
| I don't know is toaster are close to max power draw, but
| kettles certainly are.
|
| Most places with 240V regularly have 16A sockets, allowing a
| maximum draw of 3840W of power. That's the limit. Cheap fast
| kettles will often draw 3000W and boil 250ml of water at room
| tempature in 30s.
|
| Kettles in the US are often limited to 15A and thus max 1800W
| (usually 1500W) and take twice as long (60s)
|
| Technology Connections has a great video on this:
| https://youtu.be/_yMMTVVJI4c
| andrewla wrote:
| I mention Impulse Labs and their battery-assisted 120V high
| power induction range in the comments elsewhere. Seems like
| a similar concept could be used to make an incredibly
| powerful kettle; throw in a battery that charges from the
| mains, and when you ask to boil, send in 20kW and boil the
| 250ml in 4 seconds. 4.18 J/g/C * 250g *
| (1/ 20,000 kJ/s) * 75C = 3.918s
| burnerthrow008 wrote:
| For that order of magnitude to work, in practice, the
| most challenging aspect will be getting enough surface
| area between the water and heater.
|
| Otherwise, you will very quickly vaporize the water near
| the heater and the resulting lack of contact will inhibit
| heating the rest of the water volume.
| hobs wrote:
| Yeah that's a great way to start a fire with a lot of
| steam first :)
| wbl wrote:
| Microwave radiation could work to transfer heat in even
| as boiling initiates in spots. All the best kettles are
| BIS dual use items.
| JoshTriplett wrote:
| If you can transmit that amount of heat that quickly, I
| think it'd be much more convenient and feasible to have
| it in the form factor of an instant-boiling-water spout
| next to the sink, rather than a kettle. Then, rather than
| having to fill the kettle first, you directly get the
| amount of hot water you need into the vessel you want it
| in, and you can put a precise amount of heat into a
| precise amount of water flowing through a pipe to emit it
| at the right temperature.
| xyzzyz wrote:
| By the way, you can already have a boiling water tap
| today, you just buy a device that uses hot water tank to
| store the energy you rather than the battery.
| Insinkerator sells these. It might not be as energy
| efficient as the hypothetical tankless water boiler as
| described by you, because you have some losses from the
| heat slowly leaking away from the tank, but given the
| battery costs, I suspect that over the lifetime of the
| device, these losses add up to less than what battery
| costs.
| nwallin wrote:
| Correct. You can get the same power with half the voltage by
| doubling the current.
|
| The trouble is the wires. A given wire gauge is limited in
| its ability to conduct _current_ , not power. So if you
| double to the current, you'll need to have roughly twice as
| much copper in your walls, in your fuse panel, in your
| appliance, etc.
|
| Additionally, losses due to heat are proportional to the
| current. If you double the current and halve the voltage,
| you'll lose twice as much power by heading the wires. For
| just a house, this isn't a lot, but it's not zero.
|
| This is why US households still have 240V available. If you
| have a large appliance that requires a lot of power, like an
| oven, water heater, dryer, L2 EV charger, etc, you really
| want to use more voltage and less current. Otherwise the
| wires start getting ridiculous.
|
| This is not to say that higher voltage is just necessarily
| better. Most of the EU and the UK in particular has
| plugs/outlets which are substantially more robust and
| difficult to accidentally connect the line voltage to a
| human. Lots of people talk about how much safer, for
| instance, UK plugs/outlets are than US plugs. If you look at
| the numbers though, the UK has more total deaths per year to
| electrocution than the US, despite the fact the US is
| substantially more populous. This isn't because of the plugs
| or the outlets, US plugs really are bad and UK plugs really
| are good. But overall, the US has less deaths because we have
| lower voltage; it's not as easy to kill someone with 120V as
| 240V.
|
| So there's a tradeoff. There is no best one size fits all
| solution.
| masfuerte wrote:
| Your deaths claim surprised me. AFAICT England has ~10
| deaths by electrocution per year. The US has ~100 domestic
| electrocutions and even more occupational electrocutions.
| duskwuff wrote:
| How many of those deaths are attributable to electrical
| plugs, though? Given the US CPSC report at [1], I suspect
| that most of them aren't - in fact, one of the leading
| causes of electrocution deaths is "fractal wood burning".
|
| [1]: https://www.cpsc.gov/s3fs-
| public/Electrocutions-2011-to-2020...
| shaky-carrousel wrote:
| In 2017, there were 13 electrocution-related deaths in the
| UK. In the US, there are between 500 and 1,000
| electrocution deaths per year. This translates to 0.019
| deaths per 100,000 inhabitants in the UK and between 0.149
| and 0.298 deaths per 100,000 inhabitants in the US.
| Liftyee wrote:
| This is a very well written comment overall, but the energy
| loss in the wire is even worse than stated!
|
| By modelling the wire as an (ideal) resistor and applying
| Ohm's law, you can get P = I^2*R. the power lost in the
| wire is actually proportional to the square of current
| through it!
|
| Therefore, if you double the current, the heat quadruples
| instead of doubling! You actually have to use four times
| the copper (to decrease resistance by 4x and get heat under
| control), or the wasted energy quadruples too.
|
| Crucially, voltage is not in the equation, so high voltages
| - tens or hundreds of kilovolts - are used for long
| distance power transmission to maximise efficiency (and
| other impedance-related reasons).
| ajuc wrote:
| You need thicker wires for the same power. Which is why
| Americans live in constant fear of power extension cords, and
| people in EU just daisy-chain them with abandon.
| extraduder_ire wrote:
| If you're in a country that uses type-G plugs, almost* all
| of those extension cords have fuses that break well below
| the current that will cause a problem.
|
| * Currently using a cable spool which will have problems
| before blowing the fuse if it's wound up and I draw too
| much current. It has a thermal cutoff, but I still unspool
| some extra wire on the floor.
| DrBenCarson wrote:
| The higher the voltage the less power lost to resistance and
| the less money spent on copper
|
| Short protection at the breaker for every circuit would
| probably be necessary at that voltage
| UltraSane wrote:
| The skin effect causes AC current density J in a conductor
| decreases exponentially from its value at the surface J_S
| according to the depth d from the surface. The depth decreases
| as the square root of frequency. This means that the effective
| power a wire can carry decreases with increasing AC frequency.
|
| https://en.wikipedia.org/wiki/Skin_effect#Formula
| Zardoz84 wrote:
| at same time, high frequency makes high voltage secure (or
| more secure) I receive 15KV discharges at high frequency and
| I live to write about it.
| redox99 wrote:
| You could push it to 100hz, MAYBE 200hz at most. Higher than
| that, transmission losses due to skin effect would make it a
| bad idea. Also generator motors would require too high RPM.
|
| 240v is a good middle ground for safety and power.
| andrewla wrote:
| Impulse Labs has built an induction range that has super high
| power; their trick is that they have a battery that they
| recharge from the mains. Might be expensive but the same
| technique could work for a toaster (or for a water kettle) to
| basically keep a whole bunch of energy in reserve and deliver
| it when needed.
| marssaxman wrote:
| That's a great idea - I wonder if electric kettles would be
| more popular in the US if they worked as quickly as they do
| on 240V? How large a volume of battery would one need to
| accomplish this, I wonder?
| duskwuff wrote:
| I'm not sure it'd be commercially viable. A stove is a
| major home appliance, and the Impulse Labs unit is a high-
| end one with a price tag of $6000. An electric kettle, on
| the other hand, is considered a near-disposable piece of
| home electronics with a price closer to $50; it'd be hard
| to build a substantial battery into one at an affordable
| price.
| xyzzyz wrote:
| It would cost less than $50 to equip a kettle with
| appropriately sized battery. You only need something like
| 0.2 kWh of capacity.
| bobthepanda wrote:
| Electric kettles mostly aren't popular because of a
| perceived lack of need.
|
| Most Americans don't drink tea and most coffeemakers heat
| water themselves. For most other applications using a pot
| on a stove is not a deal breaker.
| Borealid wrote:
| I wouldn't want a kettle that wears out after only 3-10
| years of use.
| marssaxman wrote:
| That is a reasonable criticism, but getting three entire
| years of use from a hypothetical battery-electric kettle
| sounds like a genuine improvement to me. With a
| conventional 120V kettle, I get maybe 2-3 uses out of it
| before its overwhelming gutlessness frustrates me so much
| I can't stand to have it around anymore.
| buildsjets wrote:
| Aircraft AC electrical systems are 115V 400Hz, allegedly to
| minimize component weight.
| throw0101c wrote:
| > _Induction motors turn at a speed proportional to
| frequency, so a high frequency power supply allows more power
| to be obtained for the same motor volume and mass.
| Transformers and motors for 400 Hz are much smaller and
| lighter than at 50 or 60 Hz, which is an advantage in
| aircraft (and ships). Transformers can be made smaller
| because the magnetic core can be much smaller for the same
| power level. Thus, a United States military standard MIL-
| STD-704 exists for aircraft use of 400 Hz power._
|
| > _So why not use 400 Hz everywhere? Such high frequencies
| cannot be economically transmitted long distances, since the
| increased frequency greatly increases series impedance due to
| the inductance of transmission lines, making power
| transmission difficult. Consequently, 400 Hz power systems
| are usually confined to a building or vehicle._
|
| * https://aviation.stackexchange.com/questions/36381/why-do-
| ai...
| 6SixTy wrote:
| Very much true. A higher switching frequency means that a
| smaller transformer is needed for a given power load.
|
| In reference to consumer power supplies, only reason why GaN
| power bricks are any smaller than normal is because GaN can
| be run at a much higher frequency, needing smaller
| inductor/transformer and thus shrinking the overall volume.
|
| Transformers and inductors are often the largest (and
| heaviest!) part of any circuit as they cannot be shrunk
| without significantly changing their behavior.
|
| Ref: Page 655, The Art of Electronics 3rd edition and Page
| 253, The Art of Electronics the X chapters by Paul Horowitz
| and Winfield Hill.
| freeqaz wrote:
| Interesting to think about what the future could look like.
| What if breaker boxes were "smart" and able to negotiate higher
| voltages like USB-C does? It would avoid the problem of a kid
| sticking a fork in an outlet, or a stray wire getting brushed
| accidentally when installing a light fixture.
|
| Time will tell!
| duskwuff wrote:
| > What if breaker boxes were "smart" and able to negotiate
| higher voltages like USB-C does?
|
| That'd be difficult; a breaker typically feeds an entire
| room, not a single outlet. (And when it does feed a single
| outlet, that's typically because it's dedicated to a specific
| large appliance, like an air conditioner or electric stove,
| which wouldn't benefit from being able to dynamically
| negotiate a voltage.)
| ianburrell wrote:
| Appliances, like electric range, that need higher power
| have dedicated 240V circuits. My understanding is that 240V
| circuits use thicker cable because they usually also have
| higher current. But it is possible to convert 120V to 240V
| if only one device, sometimes done for imported electric
| kettles.
| burnerthrow008 wrote:
| > If we could magically pick a frequency and voltage for
| electrical systems to use (without sunk costs), what would it
| be?
|
| > What's the most efficient for modern grids and electronics?
|
| I do not think it is possible to answer the question as posed.
| It is a trade-off. Higher frequencies permit smaller
| transformers in distribution equipment and smaller filtering
| capacitors at point of use. On the other hand, the skin effect
| increases transmission losses at higher frequencies.
|
| If you want minimum losses in the transmission network,
| especially a very long distance transmission network, then low
| frequencies are better.
|
| If you want to minimize the size and cost of transformers,
| higher frequencies might be better. Maybe the generator is
| close to the user so transmission loss is less important.
|
| If you want smaller end-user devices, high frequency or DC
| might be more desirable.
|
| You have to define some kind of objective function before the
| question becomes answerable.
| im3w1l wrote:
| Wouldn't it make sense to do both then? Low frequency or even
| dc long distance transmission that gets converted to standard
| frequency closer to the user?
| connicpu wrote:
| There's considerable losses involved when you want to
| convert between frequencies. DC also has considerable
| losses over long distance, so there's a lower bound on the
| frequency before the efficiency starts to go down again.
| manwe150 wrote:
| Right, with modern technology my understanding is HVDC
| (essentially 0HZ?) is the way to go now (high voltage to
| minimize resistive loss, DC to minimize skin effect) if
| we were building a new grid with the same wires, but not
| economical to retrofit an existing system that is already
| working, since it is already working
| somat wrote:
| It is not that DC has more losses. it is that
| transforming DC voltage is non-trivial. With AC you just
| need a couple of magnetically coupled inductors, no
| moving parts, easy to build, efficient, reliable. With DC
| this does not work, you need to convert it to AC first do
| the transform then convert it back. Nowdays we can
| achieve pretty good efficiency doing this with modern
| semiconducting switches. But historically you needed to
| use something like a motor-generator and the efficiency
| losses were enough that just transmitting in ac was the
| clear winner.
|
| The losses over distance thing is the fundamental
| conflict between desired properties. For transmission you
| want as high a voltage as possible, but high voltage is
| both very dangerous and tricky to contain. So for
| residential use you want a much lower voltage. we picked
| ~ 200 volts as fit for purpose for this task. but 200
| volts has high loses during long distance transmit. So
| having a way to transform the current into voltage is
| critical.
|
| Some of our highest voltage most efficient long distance
| transmission lines are DC, but this is only possible due
| to modern semiconducting switches.
|
| https://en.wikipedia.org/wiki/High-voltage_direct_current
| mlyons1340 wrote:
| Power line losses are proportional to I^2R so whether its
| DC or AC isn't really the concern. V=IR so assuming R is
| constant, a higher transmission voltage results in
| exponentially lower power losses. DC is actually whats
| currently used for long distances to achieve lowest power
| line losses (HVDC).
| willis936 wrote:
| I think the question could be constrained as "what frequency
| uses the minimum amount of copper to remake the electrical
| distribution network that exists today?"
|
| This would be a pretty good approximation of the ratio of
| transmission lines to transformers.
| Panzer04 wrote:
| You could build the lot with DC and massively reduce
| transformers, but transformers are probably a lot more
| reliable than switching converters everywhere. Not sure
| which would be cheaper tbh.
| Workaccount2 wrote:
| Higher Voltage: Less conductor material needed, smaller wires.
| But need more spacing inside electronics to prevent arcing, and
| it becomes more zappy to humans. Also becomes harder to work
| with over 1kV as silicon kind of hits a limit around there.
|
| Higher Frequency: Things that use electricity can be made
| smaller. But losses in long transmission become much worse.
|
| DC instead of AC: Lower losses in transmission, don't need as
| much spacing inside electronics for arcing. But harder and less
| efficient to convert to different voltages.
| cjohnst wrote:
| When f is 60Hz, it makes for some nice round numbers, and easier
| for mental calculations.
|
| o=2pf
|
| At 60Hz, o is 376.99... very near to the integer 377.
|
| Also, Z0, impedance of free space is not far off at 376.73... O
| venusenvy47 wrote:
| This is interesting, but isn't this more like a coincidence?
| Power line engineering and wireless engineering are fairly
| distinct fields in EE.
| Aloha wrote:
| I know Southern California Edison had 50hz power, I always used
| to find old clocks and radios as a kid with a conversion sticker.
|
| I've always kept an eye out for good papers about the effort to
| convert, but they're hard to find.
| alana314 wrote:
| As a result I hear B0 everywhere, in power lines, electric arcs,
| industrial motors, speaker buzz, etc
| fahrnfahrnfahrn wrote:
| My digital guitar tuner oscillates between B and A# with no
| input.
| throw0101c wrote:
| Meta: the IEE(E) has been around for a little while. One of the
| references:
|
| > _[5] L.B. Stillwell, "Note on Standard Frequency," IEE Journal,
| vol. 28, 1899, pp. 364-66._
|
| That's 126 years ago.
| netfortius wrote:
| From a practical stand point, as someone who moved from the US to
| Europe, and was forced to leave a lot of appliances behind (not
| because of voltage - that could have been addressed!), f*ck this!
| comrade1234 wrote:
| I moved to Europe too. I have a few transformers that let me
| use my expensive American kitchen equipment (angel juicer,
| kenwood giant mixer, etc) here. Slowly I've been getting rid of
| the American equipment and replacing it with European as it's
| obvious that I'm not moving back.
| jccalhoun wrote:
| This reminds me of Wahl clippers that are designed for 60hz and
| won't work as well for 50hz.
| https://youtu.be/sZndZhK4Wuc?si=7JJlttjbzVGRb2mB
| layer8 wrote:
| To cite the actual reason:
|
| > Stillwell recalled distinctly the final meeting of the
| committee at which this recommendation was agreed upon. They were
| disposed to adopt 50 cycles, but American arc light carbons then
| available commercially did not give good results at that
| frequency and this was an important feature which led them to go
| higher. In response to a question from Stillwell as to the best
| frequencies for motors, Scott said, in effect, "Anything between
| 6,000 alternations (50 Hz) and 8,000 alternations per minute (67
| Hz)." Stillwell then suggested 60 cycles per second, and this was
| agreed to.
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