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Possible power change in the US may (probably will) affect many clock projects..... — Parallax Forums

Possible power change in the US may (probably will) affect many clock projects.....

RobotWorkshopRobotWorkshop Posts: 2,307
edited 2011-10-17 05:29 in General Discussion
This seems like a really bad idea to me. I know it will break several clock projects I've built over the years (at least 4 of them) and it sounds like it will cause issues in other projects as well.......

http://finance.yahoo.com/news/AP-EXCLUSIVE-Power-grid-apf-12144374.html?x=0&.v=2

Any thoughts?

Robert
«1

Comments

  • RDL2004RDL2004 Posts: 2,554
    edited 2011-06-27 10:23
    I don't like it at all, but they're saying 2-20 minutes a year error, which isn't much worse than a run-of-the-mill RTC chip. I can see a possible market for Internet enabled alarm clocks though.
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-06-27 10:33
    Looks like these sites may end up posting updates on this topic:

    http://www.nerc.com/

    http://ferc.gov/
  • EGMonoEGMono Posts: 31
    edited 2011-06-27 10:38
    Most of the clocks in my home are on cell phones or computer, and one that auto-corrects via radio frequency to... well, I don't know how it works exactly. The clock on the stove and microwave will be thrown off of course, but I don't set an alarm on them to wake up for work so I should be okay.

    Are the affected clocks a bad tradeoff for energy that's more reliable and less expensive to produce? I personally don't think so.
  • ercoerco Posts: 20,259
    edited 2011-06-27 10:41
    Agreed, it's time to make our voices heard and nip this idiocy in the bud, Bud! Just recently, those jokers from Lightsquared were about to go and mess up fringe GPS frequencies for telecommunicatrions, but enough people rallied and so far, Lightsquared has changed their tune: http://www.avweb.com/avwebflash/news/lightsquared_change_frequnecies_band_inmarsat_gps_fcc_204844-1.html?CMP=OTC-RSS
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2011-06-27 10:43
    This is about stupidest thing I have ever heard of " **** *** **** *** *** ***** " >.............

    :blank: the :blank:.....>:swear: The stars " * " are what I can not say on this forum

    I know that enough of that


    Here is some thing where a few company are going to make a lot of money selling NEW clock

    I had enough of electric company just doing what ever ...............>
    Are the affected clocks a bad tradeoff for energy that's more reliable and less expensive to produce? I personally don't think so. <............ I have to agree with you on this one
  • tonyp12tonyp12 Posts: 1,951
    edited 2011-06-27 10:59
    The freq will still be very close to 60Hz, Probably in the range of 59.8 to 60.2Hz
    The only thing they want to do away with is to correct the accumulated error.
    So clocks that count zero crossover ticks will not be that accurate.

    So give an official 2yr warning to engineers to stop using this technic,
    and that they need to switch to RTC ic's and coin cell battery.
    Pro:They don't start blinking 12:00 when power goes out.
    Con: Not as accurate as the 60hz (error corrected) power grid.
  • mindrobotsmindrobots Posts: 6,506
    edited 2011-06-27 11:05
    Let's see, my stomach start to grumble when I'm hungry, TIVO knows when to record things, my eyes start to droop when I should get some sleep and I have a %@$#@ cat that starts knocking stuff off the dresser at 4:30AM!!!

    Yup, I'm good to go! Power grid, knock yourself out with any frequency you want!!

    P.S. I just noticed this is my 100th post. Glad they just count quantity and not quality! Star party at my house tonight!!!
  • schillschill Posts: 741
    edited 2011-06-27 11:10
    I've been using the same clock radio since 1978 or so. Maybe the clock-maker lobby has decided it's about time for me to get a new one.
  • Mike GreenMike Green Posts: 23,101
    edited 2011-06-27 11:24
    The clock makers learned a lesson from the digital TV makers. Maybe we'll get a federally subsidized coupon for an alarm clock sync'd to WWV.
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2011-06-27 11:27
    That A real good one Mike Green
  • ercoerco Posts: 20,259
    edited 2011-06-27 12:31
    @Mike: Or an analog alarm clock "converter box" coupon. A UPS that converts 59.8 to 60.2Hz AC to DC, then back to 60.00000 Hz AC.
  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2011-06-27 16:46
    Wierd, I never heard of clocks using power line frequency to control the time. I have actually dismantled several different AC powered clocks over the years and converted them to battery power so I would have never guessed this to be the "clock's clock source".

    Since it says the West coast would run 8 minutes fast and I am always 5 minutes behind, I'll start being on time!
  • ercoerco Posts: 20,259
    edited 2011-06-27 16:54
    Certainly the old AC clocks with a 1 RPM AC synchronous motor got their accuracy straight from the power line. Neat piece at http://www.allaboutcircuits.com/vol_2/chpt_13/2.html
  • kwinnkwinn Posts: 8,697
    edited 2011-06-27 17:19
    I am pretty sure the majority of AC powered clocks get their timing from the 60Hz line frequency. Most of the early clock chips certainly did. The better ones also had battery backup and a local oscillator for power outages. I have now seen quite a few that use the GPS signals for timing.
  • tonyp12tonyp12 Posts: 1,951
    edited 2011-06-27 17:35
    The grid uses a high accuracy clock somewhere and make small adjustments to itself
    to keep the daily ticks to an exact number.

    Short term is not so accurate, as this pic shows ppm error over a 17minute span
    adv_mains2.gif
  • ercoerco Posts: 20,259
    edited 2011-06-27 17:41
    That's trending exactly the same as my Bank of America stock...
  • TimCTimC Posts: 77
    edited 2011-06-27 18:14
    It seems to fit now. The newer the clock the faster it dies
    My Cell phone - 2 Years life
    My Super fancy internet time server - 4 years life left when we all move to IPv6
    My WWVB wall clock - 5 years when it falls off the wall and drops to the floor one more time
    My stash of DS1302's they could be 10years old now - If only they were more accurate
    My Synchronous motor clock radio now 30 years old - Well it still keeps time
    My westclock baby ben wind up - ok it's a pain but it will last longer than me
    My grandfather clock - actually worth repairing in 50 years
  • RiJoRiRiJoRi Posts: 157
    edited 2011-06-28 09:02
    Screw the clocks!
    Think of all the access controls/alarm systems that use the 60-Hz zero-crossing to keep track of the time and date for scheduling. We get complaints if the time is off by the least amount. Just think -- your company's system is scheduled to disarm and unlock the doors at 7:59 A.M. One day, the employees can't get in until 8:01, or 8:15. Or the system arms not at 5:00 P.M., but at 4:48, and the moving employees trip the PIR alarms, but are locked in until the cops come. Your company gets hit with a huge fine for a false alarm.

    Freakin' lovely.

    --Rich
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2011-06-28 11:02
    Like said in my post earlier this " **** " stink es real bad

    I really hope that the power company think a lot about all the trouble they are going to cause with this idea
  • TorTor Posts: 2,010
    edited 2011-06-28 13:07
    I don't think I have seen a power line frequency-derived clock in years and years.. maybe they disappeared from Europe earlier due to the European 50Hz power line frequency? The clocks (and there used to be some) could use 50Hz as a reference, but would always need additional circuitry to be useable. The last objects I'm aware of that used the power line frequency as reference to any extent were turntable record players.

    I certainly wouldn't use a clock radio which relies on being connected to the power grid.. useless, in my opinion. At least if you wish to wake up at the right time even if there was a power flicker last night.. ;) what a relief when the first small LCD battery clock radios appeared (just in time for my engineering studies, by luck).

    -Tor
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-06-28 13:24
    It probably isn't nearly as common for new clock devices today but there were a LOT of clock projects that used the power line for timing. Typically the cycles has been closely monitored and adjusted to keep proper timing on the power coming in. At least in the area I am located the power has been working well without too many power issues. Having a battery backup circuit on the clock or using a cheap UPS can take care of any other power issues.

    Because of the 60Hz timing of the AC power many of the clock circuits are extremely simple. Here are some examples:

    http://www.intersil.com/data/an/an1342.pdf

    http://www.qsl.net/yo5ofh/hobby%20circuits/led_circuits.htm

    http://www.play-hookey.com/digital/experiments/line_clock.html

    http://www.sparetimegizmos.com/Hardware/Life_Game.htm

    http://www.sparetimegizmos.com/Hardware/AC_Monitor.htm
  • CalMarinerCalMariner Posts: 64
    edited 2011-10-15 15:06
    This is an interesting topic. They always told us that, on ships, you should always go by a battery operated clock or watch, since we did not have the fancy total-pulse-daily-counter-thingy. Now I know why. As for the DS1302's accuracy - just get the poor thing off a breadboard and into an IC socket. Mine went from a weekly accuracy of +/-30 seconds to a monthly accuracy of +/-5 seconds.
  • Heater.Heater. Posts: 21,230
    edited 2011-10-15 15:26
    Tor,
    You will be surprised to learn that most traffic light controllers in Norway and all of Scandinavia use the mains frequency to keep time. In many cases they do at least get a time update from a central system every night.
  • bill190bill190 Posts: 769
    edited 2011-10-15 19:20
    The thing is, accurate 60 Hz has been a "guaranteed" thing ever since I can remember. And because of that, many electrical engineers may have used that as an accurate time base. Actually that has always been more accurate than battery operated clocks or wrist watches - the old motor driven clock on the wall.

    So the question is, what all out there relies on this?

    Think of all those industrial and business controls and gizmos. Elevator controls in high-rises might send the cars to certain floors at certain times. Many businesses get lower electric rates during "off-peak" hours. Tons of timers and controls out there to turn things off/on at certain times. And "Time of Use" electric meters need to know what time it is. I would imagine many of those might use 60 Hz as a time base.

    This is like the Y2K problem. No one knows what all legacy stuff is out there which relies on an accurate 60 Hz??? Any electronic test equipment use this?
  • $WMc%$WMc% Posts: 1,884
    edited 2011-10-15 19:59
    Their just trying to tweak the power factor and become more efficient in poor power factor areas.This is cheaper then installing large capacitor banks and reactors to compensate for cheap low efficiency motors used in these areas.(a bunch of china Smile)
    '
    The utility can correct the power factor in a bad area and use a lot less power there. But they can still charge you the full uncorrected power factor rate and make some really good profits from this.
    '
    It just depends on where they put the rev-anew meter.Up stream of the correction or down stream. Where would you put the meter if the money was going into you bank account?
    '
    So now you know the rest of the story.
  • kwinnkwinn Posts: 8,697
    edited 2011-10-15 20:45
    bill190 wrote: »
    The thing is, accurate 60 Hz has been a "guaranteed" thing ever since I can remember. And because of that, many electrical engineers may have used that as an accurate time base. Actually that has always been more accurate than battery operated clocks or wrist watches - the old motor driven clock on the wall.

    So the question is, what all out there relies on this?

    Think of all those industrial and business controls and gizmos. Elevator controls in high-rises might send the cars to certain floors at certain times. Many businesses get lower electric rates during "off-peak" hours. Tons of timers and controls out there to turn things off/on at certain times. And "Time of Use" electric meters need to know what time it is. I would imagine many of those might use 60 Hz as a time base.

    This is like the Y2K problem. No one knows what all legacy stuff is out there which relies on an accurate 60 Hz??? Any electronic test equipment use this?

    A large percentage of the equipment I look after uses the 60Hz as a time base so it may be affected. Most run a set of standards first and test results are relative to the standards so I suspect any effect will be very minor as long as there are no frequency changes during the run.
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-10-15 20:54
    You can bet there will be an after market for frequency converters to be sold regardless if you really need it or not. ....just sayin :-)
  • AleAle Posts: 2,363
    edited 2011-10-16 01:44
    An UPS with true sinusoidal output will do, the ones with double conversion
  • kwinnkwinn Posts: 8,697
    edited 2011-10-16 14:56
    I doubt that this change will create much of a problem for several reasons.

    1 – The power grids have a number of alternators providing power to the grid in parallel. In order to do that they must all be synchronized. Any alternator attempting to run faster or slower than the rest will attempt to either drive or be driven by the others.

    2 – As a result of # 1 all the alternators on the grid need to change frequency in synchrony. This means any changes in speed will happen over a long period of time.

    3 – A lot of equipment connected to the grid has been designed to run at 60Hz, and will not run as well at frequencies that vary much from that.

    4 – To maintain close to 60Hz over the long term will still require adjusting the frequency (rpm) of the alternators once they move far enough from 60Hz.

    20 minutes per year is only a variation of 0.22831%. Other than clocks and other equipment that derives their timing from the 60Hz line this should not be a problem as long as the short term frequency does not vary much from 60Hz.
  • GadgetmanGadgetman Posts: 2,436
    edited 2011-10-17 01:15
    Frankly, if any 'critical' systems use the power lines for timekeeping, I wonder what the designers were thinking...
    (When was the last time you saw an UPS that had a guarranteed accurate 50 or 60Hz output?)
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