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