Basic Switches
Operating Characteristics
ELECTROMECHANICAL SWITCHES
Definitions below explain the meaning of
operating characteristics. Characteristics
shown in tables throughout catalog were
chosen as most significant. They are tak-
en at normal room temperature and hu-
midity. These may vary as temperature
and humidity conditions differ. Sketches
show how characteristics are measured
for in-line plunger actuation.
Linear dimensions for in-line actuation
are from top of plunger to a reference line,
usually the center of the mounting holes.
Differential Travel (D.T.)—Plunger
or ac-
tuator travel from point where contacts
‘‘snap-over’’ to point where they ‘‘snap-
back.’’
Free Position (F.P
.)—Position
of switch
plunger or actuator when no external
force is applied (other than gravity).
Full Overtravel Force—Force
required
to attain full overtravel of actuator.
Operating Position (O.P
.)—Position
of
switch plunger or actuator at which point
contacts snap from normal to operated
position. Note that in the case of flexible or
adjustable actuators, the operating posi-
tion is measured from the end of the lever
or its maximum length. Location of oper-
ating position measurement shown on
mounting dimension drawings.
Operating Force (O.F.)—Amount
of
force applied to switch plunger or actua-
tor to cause contact ‘‘snap-over.’’ Note in
the case of adjustable actuators, the force
is measured from the maximum length
position of the lever.
Overtravel (O.T.)—Plunger
or actuator
travel safely available beyond operating
position.
Pretravel (P
.T.)—Distance
or angle trav-
eled in moving plunger or actuator from
free position to operating position.
Release Force (R.F.)—Amount
of force
still applied to switch plunger or actuator
at moment contacts snap from operated
position to unoperated position.
Total Travel (T.T.)—Distance
from actua-
tor free position to overtravel limit posi-
tion.
IN-LINE PLUNGER ACTUATION
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