[time-nuts] WWVB "repeater" (was: WWV Simulator Programs)
M. Simon
msimon6808 at yahoo.com
Mon Jan 6 21:32:34 UTC 2014
May I suggest United Chemi-Con EKZM series capacitors. They are very long life electrolytics.
Data sheet: http://www.chemi-con.com/components/com_lcatalog/uploaded/8/4/4/79794946651719ba91258a.pdf
They are rated 6,000, 8,000, and 10,000 hours at load (max ripple current) depending on case size. The actual life is longer at lower temperature (below 105C) and lower current. The relationship with current and temperature is non-linear. Mouser carries them: http://www.mouser.com/Search/Refine.aspx?N=1323043&Keyword=ekzm
Reliability
http://www.chemi-con.com/index.php?option=com_content&view=article&id=11&Itemid=17
Capacitor life
http://www.chemi-con.com/index.php?option=com_content&view=article&id=12&Itemid=19
General page including the above links
Understanding The Aluminum Electrolytic Capacitor
http://www.chemi-con.com/index.php?option=com_content&view=article&id=13&Itemid=5
Simon
====
Date: Fri, 03 Jan 2014 13:25:10 -0700
From: Clint Turner <turner at ussc.com>
To: time-nuts at febo.com
Subject: [time-nuts] WWVB "repeater" (was: WWV Simulator Programs)
Message-ID: <52C71CA6.10704 at ussc.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Sometime in the late 1990s, a friend of mine who works for a local city
government asked me if there was something that I could do about some
WWVB clocks located in a conference room, downtown, on a middle floor of
an office building amongst computers and fluorescent lights that never
managed to get the correct time.
Together, we built this:
http://ka7oei.blogspot.com/2013/03/getting-atomic-wwvb-clocks-to-work.html
It's been in operation since it was installed, except for two occasions:
- After a few weeks it quit working so my friend opened the cover of the
outdoor unit to take a look. Once the water drained out, it started
operating again. (He then drilled a drain hole and sealed everything
else a bit better.)
- Last year - after somewhat more than a decade of operation - it quit
working when the electrolytics in the transformer-type "wall wart" that
powered it dried out and there was several volts of AC riding atop the
DC output. A new wall wart was procured and I added a large capacitor
in the indoor amplifier's box as well.
======
Engineering is the art of making what you want from what you can get at a profit.
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