St. John's Foucault Pendulum - Annapolis, Maryland
Posted by: Groundspeak Premium Member flyingmoose
N 38° 58.908 W 076° 29.608
18S E 370641 N 4315817
Quick Description: Located in the stairwell of the Mellon Hall.
Location: Maryland, United States
Date Posted: 6/22/2020 8:27:55 AM
Waymark Code: WM12NGW
Published By: Groundspeak Premium Member TitusLlewelyn
Views: 1

Long Description:

The Foucault Pendulum is located at the top of the four-story tower in an area which also contains the St. John's College Observatory. The pendulum drive magnet is housed within a cast iron cone in the Observatory facility. The magnet is keyed to turn on and off as the pendulum swings by using resistive photocells that determing the center of the pendulum's swing.

The magnet is triggered a fraction of a second after the "pendulum center" signal is sent to the timing circuits. The timing circuits then maintain the power to the magnet for approximately 1.24 seconds. The magnet is designed to pull the pendulum drive disk (which is mounted on the support wire) radially outward. In this fashion, the magnet and timing circuit maintain the pendulum swing against friction.

An overdrive element to the control circuit senses when the swing is too large, and shuts down the drive electronics for a time thereafter.

A more complete discussion of this assembly is forthcoming. The impetus for the current project is a gift from the Annapolis Class of 2011, which provided funds to refurbish the pendulum control circuitry. Our thanks to the Annapolis Class of 2011 for its generosity!

For additional information, please feel free to contact:
J.H. Beall
St. John's College
Annapolis, MD 21404
or by email at the St. John's College Observatory.
http://thucydides.sjca.edu/~stars/index.html

Admission Cost: 0.00 (listed in local currency)

Weight of the ball: Not Listed

Length: Not Listed

Material: Not listed

Period of oscillation: Not Listed

Rotation time: Not Listed

Hours of Operation: Not listed

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