Electric Clocks Running Fast?

In the main room of my apartment, there are three electric clocks with digital displays. One is the front panel of a clock/radio. Another is on the control panel of the stove. And the last is on the cable box (Verizon Fios, not actually cable, but that probably doesn’t make any difference).

The clock/radio and the oven clock are running fast. The cable box clock is accurate (verified by checking against my cell phone and clocks displayed on television programs).

This is a new phenomenon. It started a few weeks ago. I’ve reset the clocks three times now, and they always gain on the cable box clock.

So what could make these clocks run fast?

They’re not battery-operated. They get their power from the building electrical system. I don’t know much about electricity (or about clocks, for that matter). I know that electric watches keep time by means of a vibrating crystal, a crystal that will vibrate at a known rate when an electrical charge is applied. Do electric clocks like the ones in my apartment work differently? Could it be that they tell time by keeping track of the 60-cycle fluctuation of alternating electrical current? And if so, would something weird about the building electrical supply be causing them to run fast? Could that even happen? Could their be some problem with power?

'm assuming that the time display on the cable box is getting a time signal from Verizon, and isn’t actually a clock (that is, it isn’t keeping time itself).

Very strange. Anyone have any idea what’s going on?

Interesting. I was just going to assume Saintly Loser was crazy. :slight_smile:

Saintly Loser, how far ahead are your clocks getting? How long did it take them to get that far ahead?

The first time I reset them, they were ten or twelve minutes fast. I don’t know long it took them to get that far ahead, because I didn’t notice until they were already there.

After resetting them, seems like in about a week they’re maybe three minutes fast. I really should start logging this – then I could answer accurately.

Are these clocks plugged in or battery operated. It should be noted that the article that Sigene posted is based on an ‘experiment’ that was slated to take place over a year ago and may not have ever happened it if it did happen it may not have been put in place. I didn’t attempt to follow up on it. Besides, it’s moot it any or all of the OP’s clocks are ‘off the grid’ so to speak.

ETA I see they’re electric. You could, if you really wanted, get yourself a multimeter that can read Hz and see if your power is cycle at 60Hz like it should be.

It sounds like your power frequency is off a little. I’d suggest trying an electric analog clock. They shouldn’t be as sensitive to small freq changes. The motor could be thrown off by a big change but I suspect you’re not off by very much.

As the OP suspected, digital clocks use the AC freq to count time. Analog do too (by how fast the motor turns with the gears) but are less sensitive.

Heres a basic counter circuit. It provides output that lights up segments in the LED.

The AC gets filtered into a sync pulse. !!!! the counter counts the spikes. You can check that sync pulse with alogic probe (it lights up for each spike) or even look at it with an oscilloscope.

Overkill for an annoying fast clock. But line conditioners are strongly recommended by HP to protect their laser printers. We use them at my office to protect the web server and laser printers.


FWIW and maybe unrelated, I’ve had two Toyotas in a row with fast clocks. Yeah, they run a little fast, get a few minutes ahead, and I have to set them back.

No surprise - Japan is 10 or so hours ahead of you - the clocks are just trying to catch up.

Analog clocks are directly timed to the frequency. The motor will turn at 3600 or 1800 RPM at 60 cycles. At 60.1 cycles they will turn 3606 or 1803 RPM. In every hour the clock will gain 6 seconds. or in a day 144 seconds a day. But 0.1 cycles is a large drift off set point. A generator with a single stage mechanical governor should hold under 0.1 cycles. I would expect the gride to be ± 0.001 cycles. And advarage to 0

Don’t know about US Power generators, but in the UK you are limited to +/- 0.0000001Hz over 24 Hours. A bit tighter than the ‘Euro-grid’.
Power networks fascinate me, the idea of a society that wants power on their terms, at their rates, owned by their own nationals and still delivering a profit to a Pension. Appropriate Emoticon.

It sounds like an electrical problem with the grid. I read a newspaper article recently about some place that for some reason had a change in the hz, with resultant clock problems. I wish I could remember more about it, but at the time I merely noted it as interesting and went on to read the comics page. That only your two electric clocks are off is the main indictment.

Same experince with the clock on my Prius.

It could be dirty power. If a clock is keeping time by counting power cycles then spikes in the powerline can be counted and make the clock run fast. This is more likely in places with motors, fluorescent starters or other devices which create interference. If you or your neighbors have new devices which may be causing dirty power this might be the cause.

In this case the remedy is a low pass filter on the power wires. You can probably buy them commercially (be careful as many may be just an empty black box) but also build one yourself with a couple of inductors and capacitors or salvage from an old PC power supply.

That’s fascinating. So plug-in clocks will no longer be reliable. I don’t think Hydro-Quebec (which is not connected to the North American grid) is doing the same although I have only one or two clocks that plug in.

Back in the 50s I found out that the electric company varied its frequency during the wee hours to keep their clocks right on time, which of course kept everyone else’s on time too.

According to Sigene’s link it is an experiment:

So is there any mechanism provided for affected people such as Saintly Loser to actually make complaints to the FERC (or whoever), or is the “experiment” rigged?

Interesting. I have a Scion (made by Toyota) which in eight years I’ve never had to adjust the clock (other than for Daylight Savings Time). It’s spooky accurate.

The experiment was slated to occur in July, 2011, according to the article’s time stamp (6-24-2011), so if it did take place, it was over last year.

The U.S. has never been that tight.

To start with, the U.S. doesn’t have just one grid. It is split into three different grids. There’s an eastern grid, a western grid, and Texas (because Texas always has to be off on its own…). The Texas grid, being the smallest, has always been the most tightly controlled. I believe that they used to adjust them all to within one second over 24 hours. During the day, though, each grid could lag by several seconds, with Texas typically having the least lag of the three.

The electrical load tends to slow down the grid, so the grids will lag more and more during the day while they are under heavy load. At night when the load drops off, the grid frequency would be sped up a bit to get the long term drift back down under a second.

Controlling the grid frequency isn’t easy, by the way. If you have a single generator, it is easy to control. You just add more power to speed it up and remove power to slow it down. If you hook a second generator to that, the two end up locking together in frequency. If you add power, it speeds up itself and the difference in speed causes energy to flow from one generator to the other, speeding it up too. If you remove power, the generator starts to slow down and energy from the other generator flows into it, speeding it up like a motor. With only two generators, each generator can speed up or slow down a bit, but they are basically dragging the other one with it so it is much more difficult. Add in a few more generators, and the “grid” becomes too powerful for any single generator to affect it much. If you add more mechanical power to your generator, it can’t speed up because it can’t push all of those other generators faster. There are too many of them. So all that happens is your generator produces more power for the grid. If you remove mechanical power, all of those other generators continue pushing it, and your generator becomes a motor, powered by the grid. So by adding and removing mechanical power you can control how much power your generator adds to the grid (or even draws from it, if you remove too much), but you can no longer control the speed of your single generator.

Speeding up or slowing down the entire grid now becomes much more difficult. What you have to do is coordinate all of the generators (or at least the majority of the most powerful ones) and have them all speed up or slow down at the same time. It’s nowhere near as simple as just turning a dial somewhere.

ETA: Also, keep in mind that the entire UK grid is probably about roughly a third of the size of the Texas grid, and that’s our smallest grid. The smaller the grid, the easier it is to control.