Telechron, Inc., Ashland, Massachusetts, USA. Model Type E, c. early
1930's, serial no. 17.
Below are patent drawings. Fig. 1 is an overview of how the clock would be installed in
a power house setting to control the systems generators.
This drawing depicts the master clock. This varies slightly from the production
version. Fig. 2 is a general outline. The electrical coil below the pendulum is
replaced with a movable permanent magnet in the final version. In Fig. 3 the pilot dial
and automatic frequency control system in this version is adjusted by one of Warren's
motion reproducing motors. This was later replaced by the planetary gear system in the
production model. This motor is depicted in the drawing with three coils at the bottom of
the movement plate. The conventional motor above it, with one coil, supplies the continuos
rotation to that same pilot dial and automatic frequency control system and is unchanged.
Fig. 4 shows the commutator which is unchanged. Fig. 5 is a front elevation.
Fig. 6 shows how the motions of the commutator are translated into the rotations of
Warren's motion reproducing motor. The third coil, according to Warren's patent nearly
eliminates 'coasting' of the motor armature when violently moving back and forth to
achieve a great degree of control. Today this would be done by a standard stepping motor,
but whose design was unknown at the time.
Below is the portion of Henry Warren's patent that describes his automatic frequency
control mechanism. This is the heart of Warren's ingenious design which allows his clock
to be as or more accurate that other clocks designed for this purpose costing many times
more. However, as previously discussed, there was a weakness in that this system contained
many complicated, fast moving parts that may have made this clock unable to remain stable
and reliable over a long period of time. He claims that his "apparatus is
sufficiently sensitive to detect and correct for an error of 1/500th of a second in a two
second interval." Or 1/250th of a second per second.