Many devices in common use have AC motors whose rotational speed is tied to the AC frequency. Large variable-speed motors in things like modern elevators are synchronous motors that use a variable frequency drive to change the speed. If you take a typical record turntable (assuming you can still find one) that was built for use in the U.S and take it to Europe, it will run slow because we use 60 Hz and they use 50 Hz. The U.S. televisions were originally all synced to the 60 Hz (yes, that set the frame rate we use now). Some cheap digital devices with wall power may also sync to the 60 Hz rather than use a crystal because it is cheaper to build.
Much of Western culture is controlled by the power-line frequency because it is constant and easily available. The frequency and phase are very carefully controlled because of the extensive interconnections in the power grid. Battery-powered devices do not have this problem because they need their own frequency standard. Bryan Peterson <[email protected]> 801-422-7417 On Fri, Mar 9, 2018 at 9:00 AM, Chris Wood <[email protected]> wrote: > On Thu, Mar 8, 2018 at 9:16 PM, Barry Roberts <[email protected]> wrote: > > It's not Linux-related, but I'm curious what other nerds think. I was > > listening to KUER on the way home from work tonight, and they were > > talking about this: > > https://www.theverge.com/2018/3/8/17095440/europe-clocks- > running-slow-electricity-frequency-kosovo-serbia > > > > I don't know if I've ever owned a clock that would act like that. > > Maybe some really old clock with an AC motor. But they talk about the > > clock on a microwave, and show a digital clock on a stove. Those all > > have crystal oscillators that run on DC and I'm pretty sure would not > > be affected at all by a .1% change in the AC frequency (that number > > was from the radio --.1% or 344 seconds in about 6 months, I think). > > > > Am I crazy? Are there really a bunch of clocks in Europe that > > actually depend on the 50hz alternating current frequency for > > timekeeping? The whole thing sounds like some non-technical reporter > > grossly misunderstanding electronics to me. > > > > When I was a LDS missionary in Japan in the 90s we were warned to not > bring alarm clocks with power cords -- they needed to use batteries. > Japan runs on dual prong 100v and most US devices work just fine but > plugged in clocks will run slow. I'm not sure the science behind it > but it's related to the power feed itself. > > /* > PLUG: http://plug.org, #utah on irc.freenode.net > Unsubscribe: http://plug.org/mailman/options/plug > Don't fear the penguin. > */ > /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
