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Frequency Deviations In Continental Europe Are Causing Electric Clocks To Run Behind By 5 Minutes (entsoe.eu)

Posted by BeauHD on from the fashionably-late dept.

elgatozorbas shares a short note from the European Network of Transmission System Operators for Electricity (ENTSO-E): Apparently the Continental European Power System has been off since mid-January, causing some clocks to run behind by 5 minutes. How common are these mains-frequency synchronized clocks anyway, and why are they built that way? "The power deviations have led to a slight drop in the electric frequency," reports ENTSO-E. "This in turn has also affected those electric clocks that are steered by the frequency of the power system and not by a quartz crystal... All actions are taken by the transmission system operators (TSOs) of Continental Europe and by ENTSO-E to resolve the situation."

8 of 251 comments (clear)

  1. Simple and Cheap! by Mister+Transistor · · Score: 4, Insightful

    The reason they did that is because an AC synchronous motor was much cheaper than a quartz oscillator and solenoid like the new ones have.

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    1. Re:Simple and Cheap! by Fly+Swatter · · Score: 4, Interesting

      It was also extremely accurate, when the electric company bothers to compensate for drift. In my experience all these quartz china clocks run fast, some a few seconds and others gain a whole minute a week. It's like having a different time zone in every room (:

    2. Re:Simple and Cheap! by jmcharry · · Score: 4, Interesting

      Also they have been around since well before crystal oscillator based clocks were economically viable for consumer use. Power companies would tune the frequency to keep them within several seconds. This is going back 50, maybe 60 or more, years. They had an advantage over crystal based clocks in that long term drift was eliminated by the tuning.

  2. Re:What about fans of vinyl? by sjames · · Score: 4, Informative

    Many used induction motors and had a neon lamp illuminating markings on the side of the platter, providing a reliable 60 Hz strobe. Just tune the speed until the markings stand still.

  3. Re:AC mains is excellent if done right by fahrbot-bot · · Score: 4, Funny

    A quartz crystal has excellent short-term accuracy, but lousy long-term accuracy.

    Diamond engagement rings are like that too.

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  4. How It Works by labnet · · Score: 4, Interesting

    Mains frequency is normally very stable long term.

    Have a look here http://jorisvr.nl/article/grid...
    I would say, because of all the new renewable energy providers, it has been a much more difficult job to synchronize every body.

    Imagine you have a 10 ton flywheel in front of you and it is rotating at 49.9 times per second but you want it to be 50, and there are 300 little motors all driving the flywheel. Your job is to now coordinate everybody to match 50Hz, but where the load on the flywheel varies minute to minute. In the old days, big old power stations could slowly influence this average frequency, but now there are hundreds of windmills and solar inverters and gas turbines and nuclear and coal, all with their unique issues.

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  5. experienced this before by Anonymous Coward · · Score: 5, Interesting

    I had a digital alarm clock given to me when I was 5 years old (1978). I had it until I was ~24. It kept absolutely perfect time from 1978 until 1992, when I went off to college. Iowa State University has its own power grid and power plant. The two years I lived in the dorms on-campus, my alarm clock gained 5 minutes PER WEEK. (Yes, PER WEEK.) I got in the habit of setting it back five minutes every Sunday. I wore out the minute-advance button in those two years, fixed it a couple of times with a soldering iron. 1994 I moved off-campus and got an apartment, and boom, clock worked perfectly again, only set it twice a year for daylight savings. I asked around the engineering department and several people said, yea, ISU's power plant doesn't sync to the city's grid. I've taken apart a lot of things in my life. I've seen tons and tons of clocks' innards. Many of the mechanical ones have synchronous motors, and gearing ratios that completely and totally depend on the power grid being exactly 60Hz. It's been like that for much of the 20th century (one of the clocks I took apart was from the 1950's).

  6. Re:20 years ago by sjames · · Score: 4, Insightful

    They use a synchroscope to get the generator as close as possible to the grid before switching it in to keep stress low. Once it's switched in, it's effectively locked to the grid frequency and phase.

    In "the old days", farmers would use two incandescent bulbs in series connected across the hot lines of 2 generators. They would adjust the speed and phase until the lights went out, then throw a switch to connect them.