On 1/10/15 3:08 PM, Hal Murray wrote:
hol...@hotmail.com said:
Basically the solenoid nudged the pendulum
There was an article in Scientific American many years ago. They used a
magnet mounted on the end of a stick attached to the pendulum arm. The arc
of the magnet swung through a hole in the middle of a solenoid coil. A pulse
on the coil at the right time provided the nudge with no physical contact.
or a coil under the pendulum bob, which is ferrous, a technique used in
some large Foucault pendulums
I didn't realize you can actually buy them as a sort of catalog item..
http://www.academypendulums.com/
They put the drive at the top.
The most fascinating thing is the list of 122 pendulums they've installed
http://www.academypendulums.com/foucault-pendulum-displays.html
and some of the places they are.. there's a goodly number of museums, of
course, but some other things..Wineries, Banks, Malls?
the one in the Smithsonian was removed some years ago..
Very simple design
the schematic (and the user manual including tuning instructions) is on
the website under "manuals"
Just a photodetector driving a solenoid, which apparently draws 300 mA
from a 120VAC line.
I haven't found details on the coil or armature design, but plenty of
pictures.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
