15 ms·
Before 1948, LA's Power Grid Ran at 50hz
- dixie_land 9y agodon’t this become a moot point in retrospect? with the global trade electronics are simply made to work anywhere 100~240V 50/60Hz so the manufactures don’t have to make several different models. (They obviously still ship with different plugs but the actual converters work with almost any input)
- stevefan1999 9y agowhats the difference between 50Hz and 60Hz besides the timer shift mentioned in the article?
- Aloha 9y agoGrowing up in Southern California, I remember always finding old clocks with conversion stickers on them - I've been looking for a good source on the technical details to find out what they needed to do to accomplish the changeover. I'm not willing to pay 35 bucks to read the IEEE article however.
- baobrien 9y agoIEEE articles can be 'obtained' on Sci-Hub.
- Aloha 9y agoThank You!!
- dom0 9y agoPretty much the only way would be to either swap the gearbox connected to the synchronous motor, or the sync motor itself.
- Aloha 9y agoHaving read the article, yes this was a common way - sometimes no conversion was required. Or a new motor was required, because they were using a 60hz motor to start out with (a 60hz motor running on 50hz makes more torque), and with the frequency change the motor would no longer make adequate torque.
- zkms 9y ago> I'm not willing to pay 35 bucks to read the IEEE article however. Me neither: http://ieeexplore.ieee.org.sci-hub.cc/document/6444314/ http://ieeexplore.ieee.org.sci-hub.cc/document/6444314/
- rz2k 9y agoI have a ~10 year old GE microwave. After using a portable power generator which probably does not have a very accurate frequency, this winter when the grid was out, it seemed to switch itself over to 50Hz, and stayed that way after electricity from the grid was restored. It was very confusing as the clock consistently ran too fast, and the timer ended before food got as hot as it previously had. I was surprised that something like that would be built into the microwave, and that it would be able to guess something like that. Eventually I unplugged it for a couple hours, and it went back to normal when I plugged it back in.
- ChuckMcM 9y agoI recall finding a 'frequency converter' at a surplus store in LA from around the time of the war. Basically it was a motor generator set, the motor ran on 120V AC 50Hz and the generator produced 120V AC 60Hz. I asked about it and it was the first I had heard that LA had been 50Hz at one time. I presume it was used in a lab or something, it weighed quite a bit and didn't look like something you'd have on your kitchen counter.
- ams6110 9y agoPeople also use rigs like that to get three-phase power in areas or buildings where only single-phase is available.
- lb1lf 9y agoIncidentally, Japan faces this very issue to this day; part of the country run on 50Hz, the rest on 60Hz. This made matters trickier after Fukushima, as the nation is effectively two smaller electricity grids, not one large one - so making up for the shortfall became harder than it could have been. (However, there's a massive frequency converter interface between the two grids.) Edit: Aw, shucks - now that I revisit the article, I see the exact same points being made in that article's comment section. My bad.
- unsignedint 9y agoYes, a lot of older appliances actually had a little toggle switch to change between these. The problem still exists but many of newer machines have its own inverters so it's less of the issues...
- lb1lf 9y ago-It is not much of an issue on a micro scale - biggest issue today is probably direct-drive electrical motors, which will run too fast (if 50Hz on a 60Hz grid) or too slow (vice versa). Also, running a 60Hz motor on a 50Hz grid will cause it to run hotter (larger current than nominally on 60Hz; also, less efficient cooling as it turns slower). If the designer designed to a price point rather than to a standard, this may be an issue. On the macro scale, however, you've got a problem if, say, you suddenly lose a power plant in the 50Hz region of your country. You cannot then simply make up for the shortfall by distributing the load between all plants in the country (or, unless you're an island nation like Japan - from your neighbours, too) - only the ones in the 50Hz part of it. This is just a long-winded way of saying that the larger your power grid, the more robust it is when a power plant goes offline. The Japanese are in the unenviable position of having two small national grids rather than one large one - and, for an encore, they're on a bunch of islands and likely unable to import significant power from neighbours, too! Hence any plant downtime is felt much harder than it would any other place. Tough luck.
- Libre___ 9y agoFirst thing that came to mind here too. Wikipedia has some fascinating reading about the GE and AEG networks in Japan: https://en.wikipedia.org/wiki/Electricity_sector_in_Japan https://en.wikipedia.org/wiki/Electricity_sector_in_Japan
- deleted 9y ago[deleted]
- plorg 9y agoIt took a long time to standardize and integrate the US power grid (which even today is basically 3 loosely-connected systems). Some parts held out longer than others. My brother recently visited a hydro dam in northern Minnesota that had one turbine operating at 25hz even as recently as the 90s, serving at least one industrial customer still running equipment that predated the interconnected 60hz grid.
- lostlogin 9y agoYou prompted me to look up how power stations are synchronised. This rabbit hole leads to The War of Currents. It's worth a read. https://en.m.wikipedia.org/wiki/War_of_Currents https://en.m.wikipedia.org/wiki/War_of_Currents
- johnhenry 9y agoThe saddest casualty of war being Topsy :(.
- jakobegger 9y agoIt‘s amazing how much opposition there apparently was against AC current – a technology that noone is afraid of today.
- agumonkey 9y agoSimilarly the history of voltage levels: https://en.wikipedia.org/wiki/Mains_electricity#History_of_voltage_and_frequency https://en.wikipedia.org/wiki/Mains_electricity#History_of_v...
- camtarn 9y agoThe vibrating reed frequency meter which is the lead image in your link is super cool - never thought about a meter using tuned resonators to measure frequency instead of a discrete time-based counter.
- Taniwha 9y agohigher freq reeds were also used to switch on/off street lights and household low-tariff water heating here in NZ - hearing the switching tones coming through the stereo was part of my childhood. A local ham friend build a high power tone generator back in the 70's ... sent slow morse across town in the early hours one night by turning on/off all the streetlights in his neighbourhood
- deleted 9y ago[deleted]
- gumby 9y agoThere are other, smaller countries that have mixed frequencies. PG&E (California' primary gas and electric utility) still has DC tariffs, thought I believe they provision it by installing a converter at the pint of use. I believe this is just for elevators. Parts of Back Bay in Boston were still wired for 100V DC mains voltage into the 1960s
- seandougall 9y agoFascinating -- I'd always heard that 24 fps developed as a US film standard compared to 25 fps in Europe because of the difference in AC power frequency (24 and 60 being a pretty straightforward integer ratio). And yet, during this time, LA became firmly entrenched as the center of the American film industry while producing 24 fps films. I wonder how that squares -- was this something people had to deal with, or does this article possibly overstate how widespread 50 Hz power was?
- aninhumer 9y agoThe power frequency isn't that relevant for film, since it just powers motors on the cameras and projectors (or often just hand cranked). In fact, prior to the introduction of sound in films, the exact playback speed wasn't as important, and cinemas often varied. Where it becomes relevant is for television, and in both cases the refresh rate matches the mains frequency. PAL is 50Hz interlaced, and NTSC is 60Hz interlaced.
- acchow 9y agoI had to read further to understand why Cathode Ray Tube televisions were tied to mains frequency - it's due to an effort to reduce artefacting https://electronics.stackexchange.com/a/164252 https://electronics.stackexchange.com/a/164252
- cesarb 9y ago> PAL is 50Hz interlaced, and NTSC is 60Hz interlaced. Except for PAL-M, which is PAL but 60Hz interlaced (Brazil uses 60Hz mains frequency).
- wonderous 9y agoThis article covers the topic in more detail, but the general gist is that the film speed was controlled by the projectionist not the camera man recording the film, which was a set speed and powered by hand: http://gizmodo.com/why-frame-rate-matters-1675153198 http://gizmodo.com/why-frame-rate-matters-1675153198
- digi_owl 9y ago
- Animats 9y agoUntil the 1990s, Grand Central Station in New York had almost everything - 60Hz commercial power, 40Hz LIRR power (Pennsylvania Railroad standard) 25Hz NYC Subway power, 700VDC Metro North power, 600VDC subway third rail power, and some old Edison 100VDC power. There was a huge basement area full of rotary converters to interconvert all this. Various ancient machinery and lighting ran on different power sources. In the 1990s, Grand Central was rewired, and everything except railroad traction power was converted to 60Hz. All conversion equipment was replaced with solid state gear. It took quite a while just to find everything that was powered off one of the nonstandard systems. It wasn't until 2005 that the last 25Hz rotary converter was retired from the NYC subway system. (Third rail power is 600VDC, but subway power distribution was 13KV 25Hz 3-phase.)
- zkms 9y ago> 60Hz commercial power, 40Hz LIRR power (Pennsylvania Railroad standard) 25Hz NYC Subway power, 700VDC Metro North power, 600VDC subway third rail power, and some old Edison 100VDC power. The only thing missing is 400Hz power!
- janvdberg 9y agoThis 99% invisible episode also talks about this (third segment): http://99percentinvisible.org/episode/you-should-do-a-story/ http://99percentinvisible.org/episode/you-should-do-a-story/
- IshKebab 9y agoYeah the timing seems not coincidental.
- wolfgang42 9y agoI had a Waring Blendor [sic], cat. no. 700A, with the widest range I've ever seen: "115 Volts, 6 Amps, 25 to 60 cycle A. C. - D. C." I haven't been able to pin down an exact date on this model, but it seems to date from the 1940s or so, when the U. S. power grid still hadn't completely settled on a standard. I've read that portions of Boston still had 110 volts DC in residential areas up through the 1960s, though I've been unable to find much detail about this.
- mrlyc 9y agoThe motor on my mum's Singer Featherweight model 3-120 sewing machine runs on 110-120 volts 25-75 cycles AC and DC. It was made around 1950.
- MertsA 9y agoThat's because it's quite common for simple appliances to use a universal motor. https://en.wikipedia.org/wiki/Universal_motor https://en.wikipedia.org/wiki/Universal_motor It basically doesn't make a difference what polarity you feed it, if it's positive going into the rotor then it's positive going into the stator as well. When the rotor changes polarity, so does the stator.
- mysterypie 9y ago> customers could bring their old 50hz appliances for free adjustments and exchanges, [including] 380,000 lighting fixtures Surely ordinary light bulbs don't care about the frequency. Do they mean the electronics for fluorescent lamps? Were those common in the 1940s?
- workerIbe 9y agoI wish we still had these. I run half my house "off grid", my inverter is putting out 61Hz and my old digital alarm clock runs fast.
- MBCook 9y agoThe most recent episode of the podcast 99% invisible talked about this. Basically anything with a motor needed to be replaced or somehow changed so the motor would run at the right speed. If you didn't, your electric clocks would run 12 minutes fast every hour (for example).
- sitharus 9y agoIncandescent bulbs certainly don't care about frequency, and I can't think of a frequency-dependant component in 40s florescent lamps. The starters and ballast from that era were pretty simple, unless there's some difference for 120V operation I don't know about. Florescent lamps became really popular during WWII, so there were many around in 1945.
- deleted 9y ago[deleted]
- ryandrake 9y agoMy mind always boggles at humanity's general inability to standardize on one thing without great pain and fighting. Whether it's Metric vs. Imperial, Beta vs. VHS, Blu-ray vs. HDDVD, OpenGL vs. DirectX, USB speeds, power connectors, instant messaging protocols. Nobody can just sit together and cooperate--we always have to go through that painful period with multiple incompatible standards that fight it out until (hopefully) one of them wins.
- pmarreck 9y agoYou may be interested in this article on the general topic of interface wars: https://en.wikipedia.org/wiki/Format_war https://en.wikipedia.org/wiki/Format_war
- unabridged 9y agoLanguage is probably the oldest (and most sentimental) version of this problem
- andreasgonewild 9y agoOnly because of isolation, look at what's happened in only a few years since we got our hands on a global network.
- zanny 9y agoThere is still an incredible amount of isolation. My primary forums are reddit and hacker news, and both are so disproportionately Americo-centric its scary. Google only ever gives me results from American publications and even Duckduckgo has a hard time finding relevant information to my searches from outside the US or West Europe. Meanwhile, more people in Africa have cell phones than plumbing, and there is realistically almost nowhere in the world without some form of cellular data service now. All these people, however, are in isolated language specific silos of content. Even the Indian Internet is radically different from what I see despite both being in mostly the same language (with some Hindi mixed in). I am always worried about how little interaction there is, through a medium of effectively no barriers than the ones we make ourselves, between the people of western powers and everyone else who is currently online but either not informed about what the Internet is (and thus just uses SMS) or is isolated from us by language barriers.
- shagie 9y agoFor some other fun with California's 60hz legacy... The timezone database (maintained by the people who are very particular about making sure that a time specified is a well known time) have a note in the northamerica data file: https://github.com/tzinfo/tzinfo-data/blob/master/data/northamerica#L449 https://github.com/tzinfo/tzinfo-data/blob/master/data/north... # From Paul Eggert (2016-08-20): # In early February 1948, in response to California's electricity shortage, # PG&E changed power frequency from 60 to 59.5 Hz during daylight hours, # causing electric clocks to lose six minutes per day. (This did not change # legal time, and is not part of the data here.) See: # Ross SA. An energy crisis from the past: Northern California in 1948. # Working Paper No. 8, Institute of Governmental Studiåes, UC Berkeley, # 1973-11. http://escholarship.org/uc/item/8x22k30c http://escholarship.org/uc/item/8x22k30c
- macintux 9y agoJust when you think there might be a finite number of time/calendar pitfalls...
- aptwebapps 9y agoIt's a finite number, but it's always at least one bigger than you think it is.
- Intermernet 9y agoThat's pretty much how you prove the infinitude of primes :-)
- kens 9y agoThe story of why parts of the US used 25 Hertz power instead of the standard 60 Hertz is interesting. Hydroelectric power was developed at Niagara Falls starting in 1886. To transmit power to Buffalo, Edison advocated DC, while Westinghouse pushed for polyphase AC. The plan in 1891 was to use DC for local distribution and (incredibly) compressed air to transmit power 20 miles to Buffalo, NY. By 1893, the power company decided to use AC, but used 25 Hertz due to the mechanical design of the turbines and various compromises. In 1919, more than two thirds of power generation in New York was 25 Hertz and it wasn't until as late as 1952 that Buffalo used more 60 Hertz power than 25 Hertz power. The last 25 Hertz generator at Niagara Falls was shut down in 2006. Details: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4412948 http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4412948
- AlphaWeaver 9y ago[2015]