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I wonder how many medical &/or hospital &/or life support
devices are dependent on current based time? <br>
-Claudia<br>
<br>
On 6/24/2011 7:27 PM, walter park wrote:
<blockquote
cite="mid:BANLkTimz5VRcAjCxzimv7JwOxCoh8WD=ew@mail.gmail.com"
type="cite"><font size="4" face="Garamond"><font face="Garamond">
<p>AP story:<br>
</p>
<p>Experiment with power grid may throw off your electric
clock</p>
<p>By SETH BORENSTEIN<br>
AP Science Writer</p>
<p>06-24-2011 15:57</p>
<p>WASHINGTON (AP) _ Our power supply has been so precise that
we've set our clocks by it. But time may be running out on
that idea.</p>
<p>A yearlong experiment with the electric grid may make
plug-in clocks and devices like coffeemakers with
programmable timers run up to 20 minutes fast.</p>
<p>The group that oversees the U.S. power grid is proposing a
change that has the potential to disrupt electric clocks in
schools, hospitals and other institutions, according to a
company presentation obtained by The Associated Press. It
may also mess with the timing of traffic lights, security
systems, sprinklers and some personal computer software and
hardware.</p>
<p>Since 1930, electric clocks have kept time based on the
rate of the electrical current that powers them. If the
current slips off its usual rate, clocks run a little fast
or slow. Power companies now take steps to correct it and
keep the frequency of the current _ and the time _ as
precise as possible.</p>
<p>The experiment would allow more frequency variation than it
does now without corrections. Officials say they want to try
this to make the power supply more reliable, save money and
reduce what may be needless efforts. The test is tentatively
set to start in mid-July, but that could change.</p>
<p>Tweaking the power grid's frequency is expensive and takes
a lot of effort, said Joe McClelland, head of electric
reliability for the Federal Energy Regulatory Commission.</p>
<p>"Is anyone using the grid to keep track of time?"</p>
</font></font><font size="4" color="#ff00ff" face="Garamond"><font
color="#ff00ff" face="Garamond"><font color="#ff00ff"
face="Garamond">McClelland said</font></font></font><font
size="4" face="Garamond"><font face="Garamond">. "Let's see if
anyone complains if we <br>
eliminate it."
<p>They will and they should, timekeepers say.</p>
<p>"A lot of people are going to have things break and they're
not going to know why," said Demetrios Matsakis, head of the
time service department at the U.S. Naval Observatory, one
of two official timekeeping agencies in the federal
government.</p>
<p>The changes, however, are out of the hands of timekeepers
and in control of officials who supply the electrical power.</p>
<p>No one is quite sure what will be affected. This won't
change the clocks in cellphones, GPS systems or even on
computers, and it won't have anything to do with official
U.S. time or Internet time.</p>
<p>But wall clocks and those on ovens and coffeemakers _
anything that flashes "12:00" when it loses power _ may be
just a bit off every second, and that error can grow with
time.</p>
<p>It's not easy figuring what will run fast and what won't.
For example, VCRs or DVRs that get their time from cable
systems or the Internet probably won't be affected, but
those with clocks tied to the electric current will be off a
bit, Matsakis said.</p>
<p>This will be an interesting experiment to see how dependent
our timekeeping is on the power grid, Matsakis said.</p>
<p>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 speed-up of 2 minutes.</p>
<p>Some parts of the grid, like in the East, tend to run
faster than others. Errors add up. If the grid averages just
over 60 cycles a second, clocks that rely on the grid will
gain 14 seconds per day, according to the company's
presentation.</p>
<p>Spokeswoman Kimberly Mielcarek said the company is still
discussing the test and gauging reactions to its proposal,
and may delay the experiment a bit.</p>
<p>Mielcarek said in an email that the change is about making
the grid more reliable and that correcting the frequency for
time deviations can cause other unnecessary problems for the
grid. She wrote that any problems from the test are only
possibilities.</p>
<p>In the future, more use of renewable energy from the sun
and wind will mean more variations in frequency on the grid,
McClelland said. Solar and wind power can drop off the grid
with momentary changes in weather. Correcting those
deviations is expensive and requires instant back-up power
to be always at the ready, he said.</p>
<p>The test makes sense and should not cause too much of a
hassle for people, said Jay Apt, a business professor and
director of the Electricity Industry Center at Carnegie
Mellon University.</p>
<p>But Tim O'Brian, who heads the time and frequency division
at the National Institute of Standards and Technology, </p>
</font></font><font size="4" color="#ff00ff" face="Garamond"><font
color="#ff00ff" face="Garamond"><font color="#ff00ff"
face="Garamond">expects </font></font></font><font size="4"
face="Garamond"><font face="Garamond">widespread effects.
<p>He said there are alternatives if people have problems from
the test: The federal government provides the official time
by telephone and on the Internet.</p>
<p>Official U.S. government time: </p>
</font></font><font size="4"><u><font color="#0000ff"
face="Garamond"><font color="#0000ff" face="Garamond"><font
color="#0000ff" face="Garamond"><a
moz-do-not-send="true" href="http://time.gov/"
target="_blank">http://time.gov</a></font></font></font></u></font><font
size="4" face="Garamond"><font face="Garamond"> or call <a
moz-do-not-send="true" href="tel:202-762-1401"
value="+12027621401" target="_blank">202-762-1401</a></font></font><font
size="4"><br>
</font>
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