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Power Grid Change May Disrupt Clocks
hawguy writes with an AP story about upcoming tests of greater allowed variation in the frequency of the current carried on the U.S. electric grid: "A yearlong experiment with the nation's electric grid could mess up traffic lights, security systems and some computers — and make plug-in clocks and appliances like programmable coffeemakers run up to 20 minutes fast."
Clearly, whomever thought this was a Pretty Neat Idea hasn't read this:
http://yarchive.net/car/rv/generator_synchronization.html
and doesn't understand what happens when you're even a bunch of *degrees* out of sync, much less a few decihertz. We don't have *near* enough HVDC intertie to make this not matter, and I can't imaging how they think this is gonna work -- nothing at all on NERC's website to say what's *really* gonna happen, either.
Love all the warning, too.
20 minutes fast over the course of a year.
Such a small change can have such a big impact.
I never really thought about how digital clocks keep track of time. This is a very interesting issue.
Of course, it could also turn into a boon for the industry, having everyone buy a clock that doesnt rely on "power timing".
This is marketing speak for lower quality electricity.
I'm much more concerned about my laptop power supply and the several hundred dollars I might have to shell out if this insanity fries my laptop. Ditto for the TV and the other appliances. The other appliances belong to the landlord; but it's still no fun to have to be around and have some tech service them.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
It looks like this method for timekeeping was common in the 1930s. I work in electronics and never in my life have I seen a clock that works like this. Ive been dismantling old equipment since I could hold a screwdiver. 35 years
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beware he who would deny you access to information, for in his mind he dreams himself your master
And it's only a test/phase in to see who complains. Only very old and cheap devices used power to clock themselves. If you really need those devices to be more accurate then they are easy to retrofit externally with a brick filter or internally change the mechanism to use a chrystal or replace in innards altogether.
Most clocks are not electric .Most Run on DC provided by a Crystal oscillator, the line frequency provided by the AC line to run them is irrelevant. only electromechanical electric clocks might be in error
Honest question. How hard/expensive is it to design an electronic timekeeping device that isn't directly based on electrical current? If the issue here is that some devices are poorly/cheaply made, it would seem, on the face of it, that these clocks should be designed better, rather than designing the electrical grid around the clocks. Bit of the tail wagging the dog?
Or is this just a straw man that the electric utilities want to put forward in order to accomplish a change that has a more insidious effect on consumers?
It's easy and relatively cheap to make new devices use their own time base, but there's a huge installed base of devices that do use powerline frequency because up until now, powerline frequency has been adjusted to keep it very close to 60 hertz. So it's not a matter of the tail wagging the dog - the grid intentionally guaranteed a stable time base so clockmakers took advantage of it. It's more like the dog decided that it doesn't want to wag the tail anymore so he's having it removed.
Say goodbye to turntable strobe lights
MOD THE CHILD UP!
Twenty minutes a year amounts to about 3.27 seconds a day.
Hey, I've got 120 different clocks of my own.
analog wall clock,
thermostat,
coffee maker,
three alarm clocks in the bedroom,
microwave,
stove,
a clock in my van,
and they all show different times, some are already off by 20 minutes.
this is 2011, every one of these devices should be able to connect to the internet and synchronize time just like my PC does (should) so I can be on my merry little way.
I bought a z-wave thermostat thinking it would get it's time from the controller automagically, not the case. royally pisses me off.
Do you really want to apply firmware upgrades to all of your devices everytime congress decides to change Daylight Savings time?
Would many people really take the time to program their wireless access point's WPA key into their coffee maker so it can sync the time?
Maybe extracting the time signal from Cellular GSM signals would be easier and nearly ubiquitous. Apparently the local cell phone tower knows what timezone I'm in, so there's be no need for devices to know, though I don't know how well that works on timezone borders.
You've seriously never seen a mechanical electric clock?
I learned this as an army brat when my dad was stationed in Italy. Firstly, you had to use these shoe box-sized heavy transformers (that were passed on as soldiers moved back stateside) to transform their 220v power to 120v. But, since they're on 50 hertz instead of 60 like here in the states, clocks would run apparently slower. I suppose I could've asked my parents for a new clock, but I learned how to calculate the time offset and would reset the time (not the alarm) for when I needed to get up.
I swear to God...I swear to God! That is NOT how you treat your human!
How many people pop right up at 0'dark thirty in the morning and start getting ready for school/work/drinking without any signal? Yeah, me neither. The alarm clock allowed for the suburbs by letting employees not have to cluster around public alarm clocks (church bells, factory whistles, etc). If my alarm clock is late, I'm late, if it's early, i lose precious moments in bed (not as bad as the first case, but still irksome).
I hope this gets swatted down on behalf of every person who has to wake up before dawn and doesn't rely on their cell phone to wake them up.
Besides, my Mr. Coffee machine is PFM (Pure effin magic) in that it has a warm, freshly brewed carafe of joe waiting for me every morning, if this grid experiment screws that up, I might just go on a pre-coffee shooting rampage.
I still have quite a few clocks that work like this in my home. I mean which manufacturer is going to install a crystal in his device when he can get away with using the power source to count 1 second at every AC power inversion ?
You can test the clocks you own by plugging them into a cheap power inverter 12 volt DC to 110 AC that you can plug into the lighter plug in your car.
Get back to me when you are done. You should be surprised unless you specifically bought all the devices that have a clock in your home with that in mind.
Everything I write is lies, read between the lines.
From TFA:
The North American Electric Reliability Corp. runs the nation's interlocking web of transmission lines and power plants. A June 14 company presentation spelled out the potential effects of the change: East Coast clocks may run as much as 20 minutes fast over a year, but West Coast clocks are only likely to be off by 8 minutes. In Texas, it's only an expected speedup of 2 minutes.
My question is - will West Coast clocks run 8 minutes fast, or 8 minutes slow? My guess is that they'll be slow.
It's not so much that electric grids are designed around clocks as much as it is that a good deal of electronic devices, including, most notably, alarm clocks, that use AC power have been designed around the the fact that household current frequency is extremely uniform, and has been so for many years.
I'd be willing to lay bets that when they start messing with this, they are going to find all kinds of devices they never imagined could be affected to start failing... some quite catastrophically (ie... it stops working altogether, components burning out or shorting, etc).
File under 'M' for 'Manic ranting'
The real question is why do devices add the additional circuitry to count pulses off the mains grid rather than add additional circuitry to actually keep time?
A highly accurate crystal costs in the order for $1 for single quantities. A RTC $1-10 depending on feature set. If you already have a microcontroller you don't need the RTC either. Why are clocks etc reliant on an external signal to keep time? How do they keep time when they run on the battery which is a common backup for every $5 alarm you get?
As for streetlights ... Really? How is this not a system which gets timing from some other central authority. I don't know much about street lights, but is this something that will only affect old small town streetlights, or do the shiny new modern LED powered ones in the city act independently enough that they aren't capable of contacting an NTP server?
what happens when my spindle speed can vary by 10%? do i need to put a tach on my mill?
If the powerline frequency deviated by 10%, many things would have problems... 20 minutes/year deviation is only around .003%.
Thirty years ago I worked for the local power company in one of their large coal fired stations. I can tell you that they hold very very very close to 60hz every single second. They really can't do anything else because every generator on the grid has to be at exactly the same phase at exactly the same time. Otherwise the power from one generator cancels out the power from another generator in a big plume of fire and smoke. Even being just a little bit behind the phase, which is called motoring, is very bad for some reason.
When the public power grid was being established, a clock manufacturer petitioned successfully to have the mains time kept in perfect 60 Hz synchrony for clocks to keep time off of. This was viewed by everyone as a Big Win. After that, all you needed to make a clock was an AC motor; really nobody needed to actually bother with a real clock anymore except the people at the power station, so "the grid was the clock" the way "the network is the computer".
The power meeter in your home should calculate electrons going back and forth in the wires, a.k. current.
If the period (cycle 60HZ) changes a bit it shouldn't affect your bill. On the other end, voltage variations might have more impact since electrons moving with less voltage carry less energy (Watts) and you are usually billed by KWh.
Of course in the end, it depends on the internal workings of your meter, there are different types.
Voltage already varies quite a bit so your meter is probably already quite inaccurate ;-)
Everything I write is lies, read between the lines.
Literally the same day as I find a beautiful 1960s era plug-in wall clock in a supply closet at work...one of the really nice ones with military time pained in red numerals and everything.
I believe Older TVs use the 60 hz signal to sync. Some of this was changed and messed with when color came about. It would not surprise me to see some issues with some older analog TV''s
I remember a couple of decades ago, you could buy surplus "atomic warning clocks" that would set off an alarm, if the country was under nuclear attack. The power companies would switch the time base from 60hz to 50hz, which is what the box was designed to trip on...that 10hz change. I don't think a lot of really critical things still use the AC line frequency for a time base, but I wouldn't want to take the chance.
do surge protectors do any good in this case? { I have a desktop system hooked up through one of those.}
I listen to both RIAA and non-RIAA stuff if I like the music, tangential business/politics nonwithstanding.
Cool, meanwhile this issue will potentially affect tens or hundreds of millions of people.
I find it hard to believe that most people don't hve battery-powered clocks. Then, for computers connected to the Internet, there's NTP. So... I don't think that's a big deal.
Never heard about a line-frequency based alert system like that. Would be interested in reading more about it.
At one time there was the CONELRAD system, in which AM broadcast stations on designated frequencies would temporarily drop their carrier to trigger alarm receivers. These alarms were most commonly used by ham radio operators, who were required to go off the air immediately in event of a civil defense alert.:
http://en.wikipedia.org/wiki/CONELRAD
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What exactly is the benefit here? I kept waiting to see that somehow variable frequency power would travel farther or be more efficient, or at least save power companies some money (which I'm sure it does, or this wouldn't be happening).. but I can't imagine why or how.
Without explaining the benefit, this makes as much sense as ICANN opening up the TLDs.
And that gentlemen is: a new stimulus package. Start re-buying all your crap.
I still do not get btw, how an ethernet port is still not an option on kitchen/home appliances, all that problem would be gone, being able to adjust time from a time server. Of course an RTC module could help too :) with this specific problem.
So untrue. Maybe it was done that way in 1930. But not anymore.
You're wrong.
Line powered clocks with crystal oscillators generally use the line for the reference and the crystal for a backup during power failures.
The line has been far more accurate than a cheap crystal - at least until these goons implement their harebrained scheme.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I work for the power Industry. Frequency won't deviate any more than it does right now. Your laptops and generators and sensitive electronics won't be affected.
Right now, frequency deviates slightly just due to changes in load and generation throughout the day. Sometimes it's a little high (+.05hz at most), sometimes it a little low (-.05hz at most), it's very very rarely right at 60.00Hz. To account for this they do what they call "Time Error Correction". "Slow Time Correction" means they are correcting for a generally low frequency, "Fast Time Correction" means they are correcting for a generally high frequency. All they are talking about doing is changing the threshold for doing a Time Error Correction, or doing away with the corrections all together. This does mean that electromechanical clocks that are run directly from the grid will drift off by some unspecified amount, but they will by the only things affected.
For the El Cheapo clocks, it's less expensive to couple the 60Hz from the power transformer, thru a resistor, into a pin on the clock IC, than to provide a quartz crystal & capacitors to said chip. Even if it's only a difference of $0.10 for each unit, multiply that by millions. Remember, just follow the money. Cheaper = more profit.
Willie...
> All that I really expect is that there will be an increase in people buying UPS
Cheap clocks that rely on AC power frequency to maintain time drift just as much while on most customer grade UPS.
Everything I write is lies, read between the lines.
Or inexpensive digital clocks on microwaves/ranges/VCRs. Or most inexpensive digital clock radios.
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Oh wait, nobody uses those anyway.
Legacy systems have 60Hz real-time clock interrupts derived from line voltage.
These sorts of systems are STILL IN USE.
As well as any AC powered LED clock module from the 70's.
this is 2011, every one of these devices should be able to connect to the internet and synchronize time just like my PC does (should) so I can be on my merry little way.
There is no reason to connect to the internet, unless you want your devices to be accessible remotely. There are plenty of radio time signals that have been available worldwide for a century, or you tap into the LORAN network, or you could tap into the GPS network. Any one of these would be considerably cheaper and easier to implement than a wireless ethernet controller and NTP client.
In the 70's I developed a system to control the of the light sensitive coating onto 35mm rolls of film. This ran on a PDP-11 that used the mains cycle to keep time (20ms interupts with the UK's 50Hz supply) and measured the coating by the amount of x-rays reflected by the silver halide in the coating each second.... there were coninual errors in the accuracy of the coating as the time approached midnight.
It turns out that the National Grid was legally required to maintain a 50Hz average from midnight to midnight and would add or subtract cycles in the last minutes of the day in order to meet this requirement.
Five or so years later I was working in the National Grid Control Centre and saw the 2 clocks, one with an independent time source and one running from the mains frequency. The aim of the controllers each night was to adjust the mains frequency to bring the two clocks in sync at midnight.
Summary:
It's too hard and costly to keep supplying power at the specification everyone requires. Only redundent technology doesn't run on badly regulated power. Lets see what we can get away with...
We're talking about plug-in clocks here, which use the 60hz AC line for accurate time keeping.
I like this part.
Nope, the device won't be effected, because it updates from what should be a good source. The question is, is the broadcaster in sync with the same source?
I had a bastard of a time with a TiVo. It was fine at keeping time. I'd check it against my PC and my servers, which I *had* to keep in sync for things to work properly. The problem was, stations would be up to about +- 6 minutes. These were Series 2 TiVo's, so I had already adjusted their storage, so I had plenty of space to record. I always set it to extend the recording period to 5 minutes before the show, and 5 minutes after the end. Some stations were very predictable about their skewed times, and I could reduce that to exactly what it needed. Others drifted significantly, so I had to leave the wide window for them.
My mom's DVR through her cable company is worse. Their clock is always wrong. It also doesn't have an option to set the time manually, nor update via ntp. You got exactly what the cable company gives you, and you're shit out of luck otherwise. She knows her clock is always +- 5 to +- 10 minutes wrong. It drifts over time too, so she's never quite sure if it's early or late. By drifting, I mean it can be -5 minutes one week, and +3 minutes the next week. I'm pretty sure they use an untrained monkey with a broken hourglass to adjust their clocks daily. So her DVR is damned close to worthless without setting +-10 minutes for everything. Even still, she ends up missing shows on a fairly regular basis. Besides that, she learned that her service is absolute crap. They overcompress everything, so they can fit data down the same pipe. She missed the last 15 minutes of an NCIS episode (70 years old, and loving spy shows. hehe). I grabbed it from a torrent, burned it to a DVD, and gave it to her to watch. She showed me how the original looked, compared to the torrent version. She's using my 10 year old 32" CRT TV, so the picture shouldn't be amazing. It definitely doesn't do anything resembling HD. Still, what she gets from her provider looks like it could have come off a 10 year old overplayed VHS tape. Unfortunately, she has exactly one choice of providers where she is. Trees block the view of the sky, so she can't get satellite anything. Only one provider runs that area. The only choice is to move, but she's only 15 years into a 30 year mortgage, so she can't even sell the house for what she owes. I was tempted to teach her the evils of torrents, but I don't want to be the one responsible if she gets on the shit end of a John/Jane Doe lawsuit from the RIAA/MPAA.
[tangent mode off]
Serious? Seriousness is well above my pay grade.
UPS systems stay in sync with utility power, if a UPS system thinks the utility power is unreliable due to voltage or frequency deviations, it will go to battery. Will this require all of my UPS system to require a firmware upgrade of some sort? How will this affect my ability to parallel generators to utility? Will I need to buy new sync-check relays? I could really care less about the clocks. The question is how does this affect my data center's power reliability? All these systems were designed and built for what we have now.
The converse is, however, continuing to pay good money to do something that is completely valueless. Which makes more sense, no matter who gets the reward? Not having to readjust the Master Synchrometer (made up!) after an outage means engineers can go home earlier and suck less overtime down.
Ha! Worse yet, I've seen a hybrid mechanical electric clock. In old buildings, they used to have pneumatic clocks. Instead of each clock having an expensive motor in it, a master clock would have the motor, and put out a puff of air into tubes, which all the slave clocks would use to increment their time by a minute. So anyway, these old clocks were neat looking, and a dude I met one time had a couple. But the master clocks were hard to get, or still installed in the building. So, found a synchronous motor and built a gear and bellows system that would power his slave clocks.
These things are built on crystals too. Most electric things can be plugged into anything now, and they can't have half the world working off of 72 second minutes.
and have not been produced in mass since the 80's
besides 1 good lightning bolt and they die anyway
But what will happen when his aluminum ashtray isn't able to be machined down to the 10-thou!!!? The horror.
I work in electronics and never in my life have I seen a clock that works like this. Ive been dismantling old equipment since I could hold a screwdiver. 35 years
Wow. So you've never seen a "classic" alarm clock, analog clock with time-set knobs on the back and usually a plunger on the back that you push in or pull out to shut up/arm the annoying buzzer? Never seen electric timer, a little box that plugs into the outlet that you plug something else into, has a big round wheel with mechanical detents that you use to set the trip times? Never seen a timing motor like is in the control unit of older washing machines, a little synchronous motor that's geared to run at a particular speed? I'm not sure if they still make analog alarm clocks (these days quartz is probably cheaper, though I defy you to find a quartz alarm clock that will still function perfectly after 50 years of operation). But they still make timers (Intermatic is a common brand, your hardware store probably has them) and timing motors, both of which depend on line frequency.
Except those "highly accurate" crystals are not so highly accurate. Their frequency changes with temperature and as the crystals and other components in the circuitry age. The value of using the power line as a reference is not that it is all that accurate in the short term, it's that it is highly accurate over long periods because it is continually adjusted to be so.
Yes, your battery-backed-up clock will keep time while the power is off, but keep that clock running on battery for a month or so and you will find it inexorably drifts off the right time. You'll end up periodically having to adjust the clock manually. That's not the case if you sync to the power line -- for now, at least.
This is no big deal. What they are talking about here is the additive cycles in a day and not worrying about the compensation process for that.
Some basics:
Anything connected to the 60Hz power is at 60HZ, You can not connect a 61Hz generator to the grid.
In addition, when you connect a generator to the grid, you have to adjust its phase, as you bring it on line.
If the phase angle does not line up you get you get into a "tug of war" between multiple generation sources and that doesn't work.
The sine wave coming out of one generator has to line up with the other sine waves from the other sine waves from the other generators.
60 cycles/sec X 60 sec/min X 60 mins/hour X 24 hours/day = 5.184E6 cycle/day
What the article is talking about is the adjustment of the generating stations on the grid so that at the end of the day you get that exact number of cycles across the grid, not one more not one less. It is "really close" without tweaking but not exact.
It costs money to do those tweaks, to get the numbers on the money. That tweak right now really doesn't serve much purpose anymore.
Noting exciting, or interesting here, this is not Y2K nonsense, move along...
www.effectiveelectrons.com "chips that work" Analog, RF, Mixed Signal
They don't specify how much of a frequency swing they are talking about, but I can think of a few legacy items still in use in the music industry that are affected by line frequency.
1) - The mainstay of every old piano tuner's toolbox is the Conn Strobe Tuner.
2) - There are still thousands of working Hammond B/C series electric organs in use.
3) - Lastly let's not forget the audiophiles and their vinyl record turntables.
In fact anything with a shaded pole induction motor is speed-locked to the line frequency.
Nothing worthwhile ever happens before noon
No. If you take apart a clock radio with 4x7-segment LED display, chances are that it has a 9v battery compartment at the bottom, and an LM8560 inside. It's an IC that's been used for over 30 years and still in production. No matter how cool, modern looking, flashy blue LED display it is, it has the same IC a brown 1980s clock with red LEDs had. It could be a clone or have a different name, but it is that chip.
Guess what: it takes voltage from the transformer, before rectification, into one of the pins. It also has another pin to set 50/60Hz operation. And a SHITTY RC circuit for running off battery (useless, it's off several minutes every hour).
Another thing: most electric things CAN'T be plugged anywhere now. My grey-market XBOX 360 has a 120V power brick (I live in a 220V country). If you live in the USA, take a look at how many electronic stuff at your house doesn't even have a 220/110V switch. The only things you can pretty much plug in anywhere are chargers. Most other stuff either can't, either by design (things with motors or appliances you don't carry around), or by cost (most electronic stuff without a 110/220V switch).
No.
Greetings from Argentina.
That's what Europe does. At 8AM.
If you want a different frequency, move to a different county.
most electronic stuff without a 110/220V switch
I'm not sure the lack of a switch indicates compatibility with 110/220 line voltages of 50/60 hz freqs. For that you should read the power supply specs. For the last few years Ive been putting power supplies that work on either in my devices because they costs the same as older ones that are 110 or 220 only. Its automatic in almost all the modern switching designs i've seen. Especially with computers, the only that that's usually required is a power cord change. Its probably a supply chain issue for most companies the same way that you get RoHS stickers and lead free electronics you buy here in the US.
Very interesting argument, I tend to vouch for everything you wrote. So, the only valid point left in my parent post would be that changes in cycle rate shouldn't affect his bill. I should have kept it to the basics and simply answer the question.
Everything I write is lies, read between the lines.
I always thought the reason so much time and energy is spent making sure phases are consistant was for the sanity and proper functioning of the grid itself. With distributed generation, long runs and loads yanking on the waveform it would be total chaos to stop paying careful attention to phase matching. Obviously while the comments made by McClelland might have been stupid from a PR perspective these people are not...What am I missing?
Does anyone understand the issue or tolerances involved? How do the utilities actually benefit from this arrangement and how is it safer for the grid???
I meant that stuff made for the US usually runs in 110V only. It doesn't even have a 110/220 switch. Take a close look and you will see that only small transformers are 100-240. Your TV set has a switching power supply but chances are it only runs in 120V power.
With all the thunderstorms, brown and black outs, our clocks and other devices will never have been powered up long enough to be inaccurate before they start blinking 12:00 again :)
So, I'll get my coffee 20 minutes faster than usual?
Basically everything computer related is 100-240 auto ranging and has been for a decade or more. TV's might not be if they are designed with built in tuners because they have to change the tuner for other markets anyways so changing out the power supply is no big deal.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Voltage already varies greatly, from about 475 to 495 on my 480V nominal input according to the monitoring device on the automatic transfer switch in my datacenter. The peak is usually during the summer when they are trying to push more power through fixed sized transmission lines. In fact during the day it's rarely below about 485V.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
and have not been produced in mass since the 80's
You wanna provide a cite for that? No? I kinda doubt it, because I have an alarm clock sitting right next to me which I know from experience drifts like crazy when it's not connected to AC power, kinda indicative that it's not using the same timebase all the time, and it's only a few years old. Lots of clocks (alarm clocks especially) only use internal oscillators as a backup when running on battery, and they often don't do a very good job. And this is a Sony; the cheap ones like you'll find in millions of hotel rooms are probably even cheaper -- it wouldn't surprise me if they have no battery or internal oscillator at all.
I don't doubt that the circuits inside most of them were designed in the 80s, but that doesn't mean much.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
If only there were some way of keeping accurate time without relying on the power grid...
I don't know, maybe they could broadcast an accurate time signal via radio - doesn't need much bandwidth, so on a suitable frequency one transmitter could cover a huge area.
Or, perhaps, put a load of satellites with accurate atomic clocks in orbit - who knows, you might also be able to use this as some sort of navigation system. Alternatively, maybe its possible to produce some kind of "Protocol for Time on the Network" so that any internet-connected devices could get data from an atomic clock somewhere. Ideally, though its a bit ambitious, you could have all three.
Sadly, none of these things are feasible - the receiving end would need bulky, expensive equipment with dozens of vacuum tubes - before this could catch on you'd need to be able to build receivers small enough to be easily carried in a pocket and cheap enough for literally hundreds of users to buy- which is a pity, because then the mains grid could be saved the enormous complication of having to provide both efficient power transmission (by making short-term tweaks to frequency) and a long-term time-base service.
Of course, if these other options had already been available for many years, everybody would have upgraded by now, rather than waiting until the old system stopped working and then panicking.
In a survey of 100 programmers, 111111 thought that duck-typing was a good idea.
I have read some real bullshit replies here:)
When two generators synchronise their sinusoidal wave forms are compared and there is a resulting deadbeat oscillation, the same as when tuning a musical instrument. To avoid stressing the system mechanically, the circuit breaker switch connecting the two systems is closed at a null point in the cycle. If you get it wrong then one shaft physically tries to catch up the other. This can do physical damage and with a small generator coming on to the national grid, guess who wins.
In my time this synchronisation was done manually and the operator was responsible for closing the breaker at the right moment. Of course it is now all very automated.
However, once connected the two are linked and any variation will result in power flowing one way or other to correct the speed. For example, if the turbine fails, the generator will be driven by the grid at 60Hz (USA) or 50Hz (Europe). Only if the magnetic field (excitation) is weak, can phase slippage occur and it will produce an audible clonk as the shaft moves from one cycle to the next. Not good for the mechanics.
Various protection relays are used to disconnect generators, on faults occurring. eg: ”under frequency”, reverse power”, “under/over voltage”, “over current”, “earth fault”, “negative phase sequence” etc .
The National Grid has legal obligations to maintain the frequency at the country's standard with tight tolerances either side. Maybe just because it was once used by clocks and control systems for time keeping.
However, at times of crisis the system frequency may fall, causing a "brown out". This will result in all motors drawing more current and therefore producing more heat, possibly burning out. Your fridge may suffer. Modern lighting is also voltage/frequency sensitive and gas discharge lights (street lights for example) will start to flicker unacceptably.
Also, the generator protection systems tripping individual machines automatically at a set under frequency, for their own protection, can have a cascade effect. This was well seen in the New York blackout in 1977 and 2003.
Probably with the vast increase in small generators, wind, solar and hydro etc coming on to the grid, there is much more variation than with the old large base load generators. The use of inverters for speed control and high voltage direct current (HVDC) links (between England and France for example), and elsewhere, complicates the control of the long term average frequency.
So I think this new idea is to give the producers more leeway in letting the overall frequency vary without having to do "catchup" on the number of cycles all the time. Some old clocks may get a little less accurate.
Some other concepts:
Capacitance : Letting the grid drive the generator is used in "synchronous compensators" to introduce a capacitative load on the system which can be used to control the voltage. eg. At the end of long rural lines there can be a large voltage drop and your old TV screens can shrink noticeably. Synchronous compensation is used to correct this voltage drop.
Inductance: In large factories with many electric motors there can be an inductive load which penalizes the power supplier as he has to produce not just "active power" but this "reactive power" as well. The cosine of the phase angle between the two is called the "power factor" and is taken into account in the billing. You can think of this inductive effect as useless energy, a bit like pushing a child's swing at the wrong time and getting nowhere.
Michael Dubar
Why did we not listen to Edison. Where is tradition?
My flipping 'smart'phone is connected to the cell network, which has to know times for billing purposes, the intarwebs, which have many time services and GPS, which has incredibly accurate clocks. So that is two systems that locate where the hell it is and three ways of getting the time. Still I get notification windows every week or two asking me to set/check the time.
Now they are screwing with the 1930's technology i need to get an accurate time for my smartphone? Damn them!
They whose government reduces their essential liberties for temporary security, receive neither liberty nor security.
Every electronic device I've been buying has a switching power supply capable of rectifying and filtering voltages from 100 to 240V and 50 to 60Hz. I've seen this for the past 15 years now. Don't know why anyone would have different products these days when they can just have a small switched power supply to work on both.
Have to reset my clocks after every power outage, which is pretty often.
Really? Go take a look at EVERY electronic device at your house. Your stereo, DVD player, etc. Go, and come back with the results please.
My results?
HP charger, Motorola charger: auto 100-240
TV: Auto 90-250 (This is a set made in Brazil where they have 110 and 220 power). If it was USA I bet I would be 110 only.
XBOX360: 120V only
Stereo (1998 sony): manual 110-120-127-220-230-240
VCR: Manual 110-220
DVD: Auto 100-240
Desktop computer: 230V ONLY (ALL cheap ones now are like that. They don't have the 110/220V switch anymore).
Go and take a look, stop assuming things PLEASE.
This will disrupt other devices too. For example, my Hammond tone wheel organ will go out of tune if it isn't fed 60Hz.
"A plan fiendishly clever in its intricacies"- Homer Simpson
Maybe they're talking about really really old systems that should be replaced anyhow?
AFAIK, virtually all modern electronics run off DC - pretty much everything takes the AC from the wall plug and converts it to DC in a power supply, then generates it's own internal clock frequency using something like a crystal or some other electronic component internally?
As long as the AC/DC converter in the power supply doesn't get damaged by the frequency variation, it shouldn't really matter, should it?
We installed solar panels a couple of years ago, and they've been a Good Deal. (Like, zero electricity bills four months a year. In New England. :-)
But my jaw dropped when they explained that they won't
work during power outages(!).
The base problem is you have to avoid putting juice on the grid when a lineman's up there thinking everything's dead. Not good. There are ways to avoid this (ask anyone who has a gasoline generator hooked to their breaker box), but presumably the vendors want to keep the cost down so far as is possible.
So there are two aspects that may come to bear. First, the inverter (takes DC from solar panels and converts it to AC for the grid) is rigged to shut down immediately if there's no grid power (and wait five minutes after it comes back to resume operations). Second, it must synchronize its AC waveform to accurately match what's coming in. (Things get wasteful if it's a little out of phase, and dangerous if it's a lot out.)
So what I'm going to ask the inverter manufacturer come Monday is whether the incoming waveform is used to decide whether we've got kosher grid power. If so, will these experiments cause the frequency to depart from 60.00 Hz enough to cause the inverter to turn itself off? If so, there'll be a lot of people with solar panels who'll be very upset with these changes.
I refuse to believe corporations are people until Texas executes one. -- desert rain on http://www.dailykos.com/user/
Your instruments won't work any worse, as the frequancy will not be less precise. The only change is that extra cycles won't be compensated for at the end of the day. And that's only intresting for clocks.
Really cheap desktop computer PSUs are fixed voltage. Do you need me to send a pic of the PSU with the big red 230V ONLY sticker where the 110/220 switch should be?
Same way for US desktop computers. I'm willing to bet they're 110V only.
Except for name brand PSUs like Thermaltake, Corsair, etc. Thes still have the 110-220 switch (no auto voltage though).
Nope, I looked through the first three pages of power supplies (sorted cheapest first) on Newegg and every single on of them was labeled 100-240V, 115/230V, or 100-120V/ 200-240V. Those start at $11 so I'm not sure it's possible to buy a PC power supply here that's not capable of operation from 100 to 240V. Most of those real cheapies have the switch but go up to the $50 range and over half are auto ranging, $80 and almost all are.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Meanwhile: How much money do we lose from the clocks being wrong?
Far more. But the benefits of the proposed non-correction appear where they're easy to see and the costs are distributed where they're easy to ignore and virtually impossible to tally.
It's like "economic stimulus" that way: The jobs created are easy to see and count (though the bureaucrats overcount them anyhow). The greater number of jobs lost due to the cost of the jobs created are scattered and only show up when you start wondering why, after all this "job creation", the unemployment rate kept rising and/or the usual rebound after a recession was weak or didn't happen.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
That's actually a good idea. They could raise the price even more than $0.20!
Willie...
The reason you don't see the 110/230 switch anymore on computers is because most computer power supplies in the past few years are auto switching. I don't know what's with the 230V-only sticker on the back of yours - you might want to open the case up and read the sticker on the side of the power supply itself. I could see a 230 V only model being slightly cheaper to make (to support 110 V you need to be able to handle twice the current on the input side) but I doubt it would be worthwhile to do special runs. Pretty much everything computer I have is 100-240V, from the computers themselves to the monitors (both LCD and CRT), to speakers and printers and laptops.
Now other stuff is pretty hit and miss. DVD player is 120V 60Hz only, but thanks to region-locking it was only intended to be sold in North America anyway. Similar thing with my CRT TV, which is NTSC only.
Special runs? Over half of the world runs on 220/230V. All of Europe, most of Latin America, etc.
Also, my TV (And all Philips TVs from the last 10 years) support 90-240V and PAL-N/M/B/G/I and NTSC. PAL-N/NTSC TVs were common in my country in the early 90s, because of bootleg NTSC stuff (computers, video games, even VCRs). Then it was mostly standarized in PAL-N/M/NTSC (for a single model that also covers Brazil). And lately they added the PAL-B/G (Europe) support. Just a few cents on an extra chroma crystal and they make 1 TV set for almost the whole world (except SECAM areas)