10 ms·
The origins of 60-Hz as a power frequency (1997)
- ethbr1 2y agoIf only we could tag thought threads for submissions. Funny to see this coming out of the Baltic disconnect comment section!
- antithesis-nl 2y ago(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 2y agoThey 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 2y agoIt 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 2y agoWhat 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 2y agoI wonder if resistive heating devices like ovens which have a tuned temperature component would become systematically less accurate if the frequency changed significantly.
- smallmancontrov 2y agoNah, 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 2y ago> 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 2y agoModern dryiers are generaly run on a phase converter so while the motor is ac the frequency is controlled by a computer.
- quickthrowman 2y agoMost 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.
- ej1 2y ago[flagged]
- rkagerer 2y agoLink straight to PDF: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=628099 https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=628...
- Kelvin506 2y agoThis seems to yield only the summary, not the full paper?
- gorfian_robot 2y agoI think the full paper requires an IEEE account. :(
- rkagerer 2y agoSeems the link stopped working. When I posted, it linked straight to the PDF (I even tested in an incognito window at the time).
- Fil0sOFF 2y agoThis one seems to work https://ieeexplore.ieee.org/stampPDF/getPDF.jsp?arnumber=628099 https://ieeexplore.ieee.org/stampPDF/getPDF.jsp?arnumber=628...
- ethbr1 2y agoTl;dr - Because Westinghouse (60 Hz) beat out GE (50 Hz) in the early (~1910+) American AC electrical equipment market.
- SigmundA 2y agoMy 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 2y ago25hz too, mentioned in another thread.
- SigmundA 2y ago25hz 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_ 2y agoIn 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 2y agoBut that TLDR doesn’t answer why those companies chose those frequencies.
- Ericson2314 2y agohttps://en.wikipedia.org/wiki/Amtrak%27s_25_Hz_traction_power_system https://en.wikipedia.org/wiki/Amtrak%27s_25_Hz_traction_powe... predates standardized 60 Hz, and still hasn't been converted (!!)
- _trampeltier 2y agoSwitzerland trains still use 16,7 Hz (16 2/3Hz)
- Ericson2314 2y agoYes 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.
- cenamus 2y agoIt's also 16.7 Hz precisely (save for the fluctuations) and not 16 2/3 Hz, for some electrical reasons regarding transorming 50 Hz to 16.7 Hz mechanically, which I don't completely understand
- schobi 2y agoI understand that historically it was 16 2/3 Hz and power transfer from to the 50 Hz grid was done via 1:3 mechanical coupling with a motor and generator. That was a ratio easily achievable with gears. Nowadays with switched power supplies, this is not a problem any more. Keeping track of 16.7 Hz seems a little easier. Imagine building a numeric display for a power plant operator to see how far off you are.
- Symbiote 2y ago> Imagine building a numeric display for a power plant operator to see how far off you are. You could build a display with 3 as the denominator, and a decimal numerator: | |_ 2.1 | | \ --- | \_/ 3
- alex_young 2y ago60 Hz sure makes it easy to keep clocks on time.
- hatsunearu 2y ago1/60th of a second isn't a common unit of time though
- toast0 2y agoIt'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
- deleted 2y ago[deleted]
- theamk 2y agoAs 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 2y agoNot 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 2y agoThe 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.
- UltraSane 2y agoFun 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 2y agoThe 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 2y agoThe 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_transmission_grid#Interconnections https://en.wikipedia.org/wiki/North_American_power_transmiss...
- cf100clunk 2y agoExactly, 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 2y agoWe 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 2y agoSame with mainland Australia and Tasmania with HVDC cable going through the sea.
- voxadam 2y ago(1997)
- 1-6 2y agoDuodecimal Society members are happy.
- pkulak 2y agoI 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 2y agoIt'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 https://www.youtube.com/watch?v=DyqjTZHRdRs&t=49s
- makerdiety 2y agoThe 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 2y agoYes! 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 2y agoWell, 50 Hz means the period is a round 20 ms instead of 16.6666… ms. And PAL got a higher resolution thanks to it.
- pkulak 2y agoAt the cost of framerate. No free lunch!
- tzs 2y agoAnother point in favor of 60 is there are 60 seconds in a minute and 60 minutes in an hour. If you make the frequency 60 cycles/second then you only need divide-by-60 circuits to derive 1 cycle/second, 1 cycle/minute, and 1 cycle/hour. With 50 cycles/second you would need both divide-by-50 and divide-by-60.
- freeqaz 2y agoIf 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 2y agoI don't care what the frequency is, I just want my LEDs to not flicker!
- sxp 2y agoNormal 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.
- xanderlewis 2y agoWhat about if they flickered at 10^-15Hz?
- viraptor 2y agoThat would be really annoying to tell if they're broken, or just currently in the "off" phase :)
- xanderlewis 2y agoAssuming they started on, you’d be lucky if they lasted long enough to ever reach their off state (~32 million years later).
- SSLy 2y agothat means that either the breaker is faulty, or the power stabilizator in the lamp itself is junk.
- cjohnst 2y agoWhen f is 60Hz, it makes for some nice round numbers, and easier for mental calculations. ω=2πf At 60Hz, ω is 376.99... very near to the integer 377. Also, Z₀, impedance of free space is not far off at 376.73... Ω
- venusenvy47 2y agoThis is interesting, but isn't this more like a coincidence? Power line engineering and wireless engineering are fairly distinct fields in EE.
- cjohnst 2y agoCoincidence, maybe, but convenient. That currently may be the case that many or most engineers rarely use both. But, from a historical perspective, when power generation and distribution were new, there was probably not such a distinction. Even today, large industrial users of power need to know and understand the types of equipment they're using, impedance and power factor of them, and the aggregate effect on the power grid, and adjust for it. I imagine that many of the early large users of power were radio broadcasters. There was likely significant overlap of power engineering and wireless broadcasting. An engineer would need to understand what effect the broadcast system was having on the grid and adjust for it. Calculating the impedance of the entire system using ω and the associated capacitance and inductance of portions of the system. The broadcasting antenna would certainly be a part of calculating power draw and power factor.
- kalleboo 2y agoI'm not an electrical engineer so what makes integer 377 easy for mental calculations? It's seems like 50Hz would be even more convenient because ω = pi*100
- Aloha 2y agoI 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 2y agoAs a result I hear B0 everywhere, in power lines, electric arcs, industrial motors, speaker buzz, etc
- fahrnfahrnfahrn 2y agoMy digital guitar tuner oscillates between B and A# with no input.
- throw0101c 2y agoMeta: 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 2y agoFrom 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 2y agoI 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 2y agoThis reminds me of Wahl clippers that are designed for 60hz and won't work as well for 50hz. https://youtu.be/sZndZhK4Wuc?si=7JJlttjbzVGRb2mB https://youtu.be/sZndZhK4Wuc?si=7JJlttjbzVGRb2mB
- layer8 2y agoTo cite the main origin: > 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.
- mrb 2y agoThe 60 Hz grid is why we have HDDs spinning at 7200 RPM. Because of 60 Hz, it was simpler to design AC electrical motors to spin at 3600 RPM or 7200 RPM (1x or 2x factor). When DC motors were made, for compatibility with AC motors, they often spun at the same speed (3600 or 7200 RPM) even though there was no electrical reason to do so. When HDD manufacturers selected DC motors for their drives, they picked 3600 RPM models as they were very common. Then, for performance reasons, in the 1990s, 7200 became more common than 3600 eventually.
- hcarvalhoalves 2y agoAlso 5400rpm HDDs were common – that would be 1,5x factor.
- emmelaich 2y agoThere was a brief stop off at 5400 at long the way. Actually, still available. Good to have something quieter when performance requirements are not as high.
- kees99 2y ago5400 is (was?) very common RPM for laptop HDDs.
- Tempest1981 2y agoAnd apparently why we have LED car taillights that flicker annoyingly. If anyone here works at a car manufacturer, please try to get this fixed. Apparently not everyone notices.
- arcanemachiner 2y agoI see it, but only in my peripheral vision. Drives me nuts.
- spockz 2y agoOr for some reason in the rear view and side mirrors!
- alexjplant 2y agoTangentially related: I have a vague memory of reading somewhere that the PCM sampling frequency for CD Audio was decided between Sony and Phillips by way of a surf contest. Their respective frequencies of choice were such that they could fit some arbitrarily-long piece of classical music onto a single disc so they decided to battle it out on the waves (the conference where they were hashing this out was in Hawaii). Phillips supposedly won so we got 44.1 kHz. I just did a cursory web search to find this anecdote and was unsuccessful. Did I make this up whole cloth or is it just buried someplace? Or was I bamboozled at a young age by some random forumite on a now-defunct site? *EDIT: This comprehensive account [1] seems to confirm that the story is completely apocryphal. [1] https://www.dutchaudioclassics.nl/The-six-meetings-Philips-Sony-1979-1980-The-Start-of-Digital-Audio/ https://www.dutchaudioclassics.nl/The-six-meetings-Philips-S...
- deleted 2y ago[deleted]
- hunter2_ 2y agoSony won, not Philips. It seems that the rationale is like so: a higher rate would not be compatible with both NTSC and PAL VCRs, and a lower rate would shrink the transition band for the antialiasing filter (or alternatively, reduce usable audio bandwidth to an extent that encroaches on the generally accepted limit of human hearing). Although the latter hardly seems relevant when the alternatives being debated were so close (Philips' 44056 Hz, for example)! https://en.wikipedia.org/wiki/44,100_Hz#Origin https://en.wikipedia.org/wiki/44,100_Hz#Origin
- anticensor 2y agoWhy couldn't they make use of a sampling rate with five samples per frame (which would exactly give 88.2kHz by the way)?
- wappieslurkz 2y agoBecause doubling the sample rate would half the playing time of a CD, or require twice the density, while not bringing any audible increase in quality for the human ear.
- aetherspawn 2y ago50 factors 1 2 5 10 25 50 60 factors 1 2 3 4 5 6 10 20 30 60 Seems for AC 60 is overall more flexible in design of AC motors, transformers and other resonant devices
- Dylan16807 2y agoOnly if you need to align to a second for some reason. 50Hz is still 60 cycles per something.
- gorfian_robot 2y agorelatives living in Australia (a 50Hz county) but with family in the US decided in their new home to provide both 50Hz power with Australian style outlets and 60Hz with US style outlets since many household appliances are much cheaper and diverse in the US. since they built the place with a solar/battery system it wasn't too big of a deal to use two different inverters for the AC side of things.
- cwmoore 2y ago"Effects of a 60 Hz Magnetic Field Exposure Up to 3000 μT on Human Brain Activation as Measured by Functional Magnetic Resonance Imaging" 2015 Alexandre Legros, Julien Modolo, Samantha Brown, John Roberston, Alex W Thomas https://pubmed.ncbi.nlm.nih.gov/26214312/ https://pubmed.ncbi.nlm.nih.gov/26214312/
- mrlonglong 2y agoAll that's academic now we have power supplies that are capable of handling both frequencies and the various voltages in use across the globe.