Author Topic: They can have my 60 hz (Read 7864 times)

never_retreat · « **on:** June 25, 2011, 02:06:36 PM »

They can have my 60 hz when the pry it from my cold dead hand.
http://news.yahoo.com/s/ap/20110625/ap_on_hi_te/us_sci_power_clocks

zahc · « **Reply #1 on:** June 25, 2011, 02:15:31 PM »

I've been reading this with interest. I'm trying to think of anything that actually requires a very accurate mains frequency but there isn't much anymore. The articles are very annoying because they don't actually say how much slop they are going to allow; they say some stupid figure like 20 seconds per year like that is meaningful...I hate that...that's the one thing you need to know, but they don't say, because that would confuse everybody.

have one of those mechanical clocks with the flip-over numbers in the garage. I've always loved that thing because it's very accurate and easy to see. My enlarger timers also are AC-syncronous, but I don't think that will affect my precision very significantly. Really, there's not much out there nowadays that depends on a very accurate mains frequency. TVs used to use it, but now I think they have that blanking interval or whatever, but any very old B&W TVs out there might not work anymore. It would help if we knew how bad the variation was going to be...

Does anyone here know anything about Technics turntables? I have an SL1600 that has a strobe for you to adjust the speed with, but I don't know if the strobe itself is sync'd off the mains or of it has its own crystal source. And I don't know if this turntable speed itself will change if the mains frequency changes. I also don't think it's that big of a deal, but I was just wondering.

AJ Dual · « **Reply #2 on:** June 25, 2011, 03:29:43 PM »

I'm trying really hard to think of anything that isn't an antique that relies on mains current signal to keep time.

Even if the grid did a better job of maintaining perfect 60hz I'd ASSUME it would fail or be off-spec at random times and not design anything, even the cheapest consumer electronics to use it to keep time.

Doggy Daddy · « **Reply #3 on:** June 25, 2011, 04:31:30 PM »

Quote from: zahc on June 25, 2011, 02:15:31 PM

Does anyone here know anything about Technics turntables?

No, but I have concerns about my Luxman. I guess I'll either get motivated and do a bit of research or I'll just wait and see how it all sounds. Probably the latter...

DD

BTW, I remember and like the 1600.

Edited to add:

Quote

Description

The SL-1600 mk2 reflects many of the developments which have made Technics a leader in the turntable industry, while adding some new features of it's own.

To begin with, it combines quartz phase locked speed accuracy with high torque and near instantaneous start-up. Quick stops are also provided by an electronic braking system

I think you'll be okay.

TommyGunn · « **Reply #4 on:** June 25, 2011, 06:05:58 PM »

First they **** the television and make me get digital cr*p -- which doesn't work half the time, and when it does, the cable company keeps moving CBS from channel 115.3 to channel 92.3 and then to 119.5632 and then to 72.3 ---- I won't bother to mention what's happened to the other networks

And now they're fritzing around with our 60hz power!
G*D**N bunch of *********
Is NOTHING sacred?
I am seriously p'o'd about this!!!!!!

mtnbkr · « **Reply #5 on:** June 25, 2011, 06:32:47 PM »

I bet you got pissed off when they stopped making buggy whips too.

Chris

TommyGunn · « **Reply #6 on:** June 25, 2011, 07:02:20 PM »

No, you don't need buggy whips to ride a horse.

HankB · « **Reply #7 on:** June 25, 2011, 08:02:36 PM »

American quality control, slipping again with .gov approval . . .

RocketMan · « **Reply #8 on:** June 25, 2011, 08:06:59 PM »

I can see problems with master/slave clock systems in a lot of schools and other .gov bldgs. Plus some commercial buildings that use master/slave synchronous clocks. There are still quite a few of those still being sold out there by companies like American Time & Signal and National Time & Signal.
In many cases the master clock receives an accurate time signal from an outside source, and syncs the slave clocks to that once per hour. That's how the clocks on our RDC work, so we shouldn't have any issues. (I knew there was a reason I started changing some of our clocks over to digital units two years ago.

) But I suspect some cheap .gov organizations still rely on their master clock being sync'd by 60Hz mains.

MechAg94 · « **Reply #9 on:** June 25, 2011, 10:58:03 PM »

I am wondering if high voltage switching systems that operate within a few cycles or big motors that operate at speeds governed by multiples of the frequency would be affected. If it isn't really that much change, probably not.

Jim147 · « **Reply #10 on:** June 25, 2011, 11:03:17 PM »

Quote from: MechAg94 on June 25, 2011, 10:58:03 PM

I am wondering if high voltage switching systems that operate within a few cycles or big motors that operate at speeds governed by multiples of the frequency would be affected. If it isn't really that much change, probably not.

Stolen from another discussion on this topic.

Quote

motor rpm = (120 * Frequency) / number of poles

2 pole motor, 60 Hz = 3600 rpm (synchronous)
2 pole motor, 58 Hz = 3480 rpm
2 pole motor, 62 Hz = 3720 rpm

jim

KD5NRH · « **Reply #11 on:** June 25, 2011, 11:30:33 PM »

Quote

"Is anyone using the grid to keep track of time?" McClelland said. "Let's see if anyone complains if we eliminate it."

I notice they don't mention how or where to complain. Cute tactic.

MechAg94 · « **Reply #12 on:** June 25, 2011, 11:55:20 PM »

Quote from: Jim147 on June 25, 2011, 11:03:17 PM

Stolen from another discussion on this topic.

jim

motor rpm = (120 * Frequency) / number of poles

2 pole motor, 60 Hz = 3600 rpm (synchronous)
2 pole motor, 58 Hz = 3480 rpm
2 pole motor, 62 Hz = 3720 rpm

That is why I am thinking they are probably talking about 60.1 Hz to 59.9 Hz or something small like that. RPM changes like those above would affect industrial equipment all over the country.

As mentioned, they don't say what the current versus new ranges are.

MechAg94 · « **Reply #13 on:** June 26, 2011, 12:08:01 AM »

Quote

Frequency protective relays on the power system network sense the decline of frequency and automatically initiate load shedding or tripping of interconnection lines, to preserve the operation of at least part of the network. Small frequency deviations (i.e.- 0.5 Hz on a 50 Hz or 60 Hz network) will result in automatic load shedding or other control actions to restore system frequency.

Toward the bottom of this page.
http://en.wikipedia.org/wiki/Utility_frequency

Another thought that is on the edge of my electrical understanding: If the frequency drifts more, I would think that would mean various generation units all over would have issues matching the line frequency and more end up with more unproductive power generated. I don't know the numbers on that. It might not be an issue.

MechAg94 · « **Reply #14 on:** June 26, 2011, 12:09:53 AM »

http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm
This has a chart of frequency on the British grid.

KD5NRH · « **Reply #15 on:** June 26, 2011, 01:16:36 AM »

Quote from: MechAg94 on June 26, 2011, 12:08:01 AM

Another thought that is on the edge of my electrical understanding: If the frequency drifts more, I would think that would mean various generation units all over would have issues matching the line frequency and more end up with more unproductive power generated. I don't know the numbers on that. It might not be an issue.

More critically, how many backup and/or filtered power systems detect non-60-Hz-ness as a "dirty power" condition and disconnect from the grid? Most of the smaller systems aren't really built to be failing over to backups or shutting down the protected equipment several times a day.

230RN · « **Reply #16 on:** June 26, 2011, 04:42:20 AM »

Quoted from RocketMan
"cheap .gov organizations"

^ oxymoron alert ^

Well, as long as they don't screw up the cesium clock in Boulder.

Or the first octave pipes in all those Wurlitzer organs.

Except for those two , I don't care.

I'm not signing this one so nobody will know who posted it.

CNYCacher · « **Reply #17 on:** June 26, 2011, 09:11:08 AM »

Hold the phone!

By my calculations regarding the 20-minutes-per-year quotation, that means that the grid might average 60.0022816 Hz over the year

Excuse me if I cease to worry about this.

birdman · « **Reply #18 on:** June 26, 2011, 09:20:18 AM »

Quote from: CNYCacher on June 26, 2011, 09:11:08 AM

Hold the phone!

By my calculations regarding the 20-minutes-per-year quotation, that means that the grid might average 60.0022816 Hz over the year

Excuse me if I cease to worry about this.

I think you are right, which is why I haven't been worried...I was waiting to see how long it took someone to do the math on the minutes per year. BUT before you completely stop worrying, thats the maximum average drift over the year of a device that integrates a frequency count (I'm treating this like a gyro), so the instantaneous frequency drift may be much higher (still not likely very high, but more than 0.002hz)

KD5NRH · « **Reply #19 on:** June 26, 2011, 09:42:12 AM »

Quote from: CNYCacher on June 26, 2011, 09:11:08 AM

By my calculations regarding the 20-minutes-per-year quotation, that means that the grid might average 60.0022816 Hz over the year

50Hz one day and 70Hz the next gives a perfect 60Hz average.

cassandra and sara's daddy · « **Reply #20 on:** June 26, 2011, 10:33:54 AM »

turntables?! oh my

Doggy Daddy · « **Reply #21 on:** June 26, 2011, 11:56:32 AM »

Quote

I'm not signing this one so nobody will know who posted it.

« Last Edit: Today at 02:05:57 AM by 230RN »

Aw, c'mon! Not even a clue?

DD

birdman · « **Reply #22 on:** June 26, 2011, 02:59:37 PM »

Quote from: 230RN on June 26, 2011, 04:42:20 AM

Quoted from RocketMan
"cheap .gov organizations"

^ oxymoron alert ^

Well, as long as they don't screw up the cesium clock in Boulder.

Or the first octave pipes in all those Wurlitzer organs.

Except for those two , I don't care.

I'm not signing this one so nobody will know who posted it.

I believe the most accurate current time standards all use rubidium now, not cesium. (just FYI)

230RN · « **Reply #23 on:** June 26, 2011, 05:16:44 PM »

Quote

I believe the most accurate current time standards all use rubidium now, not cesium.

Rats.

Phooey.

Fiddleysquarts.

Boy, am I behind the times.

"Give a man the time and he will know it for an instant. But give him a 360 Hz tuning fork and he will have the correct time forever."

This all reminded me that I gotta go wind up my sundial. I forgot to yesterday.

birdman · « **Reply #24 on:** June 26, 2011, 05:34:57 PM »

Quote from: 230RN on June 26, 2011, 05:16:44 PM

Rats.

Phooey.

Fiddleysquarts.

Boy, am I behind the times.

"Give a man the time and he will know it for an instant. But give him a 360 Hz tuning fork and he will have the correct time forever."

This all reminded me that I gotta go wind up my sundial. I forgot to yesterday.

And with three tuning forks, will know what direction he's going :)

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Author Topic: They can have my 60 hz (Read 7864 times)