Timex DYNABEAT 253 - Page 10

Operation of the Model 253 Movement
FIGURE C
CONTACT PIN
FIGURE D
CON TACT SPRING
It lis necessary to dismantle the
mechanism to observe the action
of - the movement mechanism.
Remove the stem (described on
Page 253.4), the energy cell re-
taining spring and the energy cell.
Remove
the shunt bridge as de-
scribed on Page 253.5 and replace
the shunt bridge screw and
tighten.
To observe the action of the con-
tact spring and contact on the
balance assembly, proceed as fol-
lows
(see Figure Cl .
Rotate the balance assembly slow-
ly from the rest (neutral) position
using very light pressure (i.e. a
clean brush). The instant the con-
tact spring touches the contact
pin on the balance (see Figure
0), current flows through the bal-
ance coil. The current induces a
magnetic field which opposes the
field of the permanent magnet
and imparts an impulse to the
balance assembly.
The purpose of the contact jewel
is to limit the contact between the
contact spring and the contact pin
in
order that the flow of current
occurs at the proper position dur-
ing the rotation of the balance
assembly.
After the balance returns to its
neutral position the same contact
process is repeated in the opposite
direction (see Figure E) .
The above action is the source of
mechanical power to drive the
movement.
253.9