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Speedy clocks - why?

R

Ralph & Diane Barone

Ken Taylor said:
Most likely just the frequency of the power supply has risen enough to make
10 minutes in 24 hours (as it appears to be that sort of period). Any clock
with a mains-derived reference will be affected, whereas the others are
likely crystal controlled and unaffected.

Ken
Click to expand...

Makes some sense, but Sault St Marie should be on the same synchronous
power grid as the rest of the east coast of North America and there are no
reports of clocks jumping ahead in Florida or New York. What this sounds
more like is a harmonic resonance in the Sault St Marie area which is
causing enough higher harmonics to create extra zero crossings in the AC
waveform. Any cheap clock that just counts zero crossings to derive time
will run fast in the presence of large amounts of voltage harmonics.
 
K

Ken Taylor

John Larkin said:
me=Local+News


These people should hang an oscillscope on the AC line. The waveforms
should be interesting.

John
Click to expand...
Way easier to write a startling letter to the Editor.

Ken
 
N

nospam

John Larkin said:
These people should hang an oscillscope on the AC line. The waveforms
should be interesting.
Click to expand...

Will be a boring sinewave the same as any other.

Hanging on a frequency counter would be more interesting, however, they
already have a town full of mains frequency counters and they are all
saying the same thing - too high by about 0.7%.

The real mystery is how people consider something so bloody obvious to be a
mystery.
 
S

Stefan Heinzmann

Jan said:
Looks like generator not at 60Hz, but running fast?
Are they not locked to an other grid?
Why do they not mention frequency?
Strange.
10 minutes in 24 Hours is 600 / 24 x 3600 6.9E-3 should be 60.41Hz
Did I goof on the math? Probably.
Click to expand...

As several people here have noted the fault is blatantly obvious: The
power station failed to control the mains frequency properly. What
strikes me is the apparent cluelessness or incompetence of the power
station staff. I can sort of accept that their spokesman has no clue and
utters the usual bullshit, but their engineers at least ought to have an
idea what they are dealing with.

I hope this is not an indication of the general state of affairs in US
power stations...
 
R

Ralph & Diane Barone

Stefan Heinzmann said:
As several people here have noted the fault is blatantly obvious: The
power station failed to control the mains frequency properly. What
strikes me is the apparent cluelessness or incompetence of the power
station staff. I can sort of accept that their spokesman has no clue and
utters the usual bullshit, but their engineers at least ought to have an
idea what they are dealing with.

I hope this is not an indication of the general state of affairs in US
power stations...
Click to expand...

I sincerely doubt that Sault St Marie is located in a non-integrated
portion of the power system. Now perhaps Hydro One was doing some sort of
transmission maintenance, temporarily islanded that area and did a lousy
job of regulating the frequency, but I'm still betting on a harmonic
resonance in that area.
 
J

John Larkin

I sincerely doubt that Sault St Marie is located in a non-integrated
portion of the power system. Now perhaps Hydro One was doing some sort of
transmission maintenance, temporarily islanded that area and did a lousy
job of regulating the frequency, but I'm still betting on a harmonic
resonance in that area.
Click to expand...

The critical question is whether synchronous-motor-type clocks gained
time, or only electronic ones.

John
 
J

Jan Panteltje

I sincerely doubt that Sault St Marie is located in a non-integrated
portion of the power system. Now perhaps Hydro One was doing some sort of
transmission maintenance, temporarily islanded that area and did a lousy
job of regulating the frequency, but I'm still betting on a harmonic
resonance in that area.
Click to expand...
What is against harmonics / distortion of the wave form is the rather small difference,
and the fact it was that was for at least 2 days, and over a wider area the same.
How would you explain that?
In the sixties I made a mains powered times, but even that needed a lowpass.
(Took 100Hz from a bridge).
One electric clock I have here has small synchronous motor....
Sort of unlikely for that to slip that way?
JP
 
M

Mike

As several people here have noted the fault is blatantly obvious: The
power station failed to control the mains frequency properly. What
strikes me is the apparent cluelessness or incompetence of the power
station staff. I can sort of accept that their spokesman has no clue and
utters the usual bullshit, but their engineers at least ought to have an
idea what they are dealing with.

I hope this is not an indication of the general state of affairs in US
power stations...
Click to expand...

I don't know why it should, any more than what goes on in France should
indicate the state of affairs in Germany.

Besides, we can't annex Canada till we're done in Iraq.

-- Mike --
 
T

Tom Del Rosso

nospam said:
Will be a boring sinewave the same as any other.
Click to expand...

Mine is a series of straight lines approximating a sine wave. About 10
individual lines make a complete cycle, so it's a very rough
approximation.

The real mystery is how people consider something so bloody obvious
to be a mystery.
Click to expand...

The mystery is what's causing it. I'd also like to know why mine is
straight lines.
 
J

Jan Panteltje

Mine is a series of straight lines approximating a sine wave. About 10
individual lines make a complete cycle, so it's a very rough
approximation.



The mystery is what's causing it. I'd also like to know why mine is
straight lines.
Click to expand...
You are looking at the output of a DC to AC converter?
 
S

Stefan Heinzmann

Mike said:
I don't know why it should, any more than what goes on in France should
indicate the state of affairs in Germany.

Besides, we can't annex Canada till we're done in Iraq.
Click to expand...

Oops, I didn't realize it was in Canada, sorry!
 
S

Spehro Pefhany

The critical question is whether synchronous-motor-type clocks gained
time, or only electronic ones.

John
Click to expand...

I wonder if anyone still has that kind of clock. I know we don't have
any in our house. The last ones would probably be owned by older
people with even older stoves or stand-alone clocks. I don't think
I've seen them among the retro design items like old-fashioned fans
and such like.

Best regards,
Spehro Pefhany
 
J

Jan Panteltje

I wonder if anyone still has that kind of clock. I know we don't have
any in our house. The last ones would probably be owned by older
people with even older stoves or stand-alone clocks. I don't think
I've seen them among the retro design items like old-fashioned fans
and such like.
Click to expand...
That is because they last for ever, I bought this one in the seventies
IIRC.
Has an alarm too, and I use it (backed up by the cellphone).
JP
 
S

Spehro Pefhany

That is because they last for ever, I bought this one in the seventies
IIRC.
Click to expand...

Seventies? Does it have the "digital" flip card display? Those things
are probably worth money as collector's items.
Has an alarm too, and I use it (backed up by the cellphone).
JP
Click to expand...

Best regards,
Spehro Pefhany
 
J

John Larkin

I wonder if anyone still has that kind of clock. I know we don't have
any in our house. The last ones would probably be owned by older
people with even older stoves or stand-alone clocks. I don't think
I've seen them among the retro design items like old-fashioned fans
and such like.

Best regards,
Spehro Pefhany
Click to expand...

See s.e.d.

John
 
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