Samson 3374 - Design and Principle of Operation; Fail-Safe Action; Versions

EB 8331-3 EN 3-1
Design and principle of operation
3 Design and principle of oper-
ation
TheType3374ElectricActuatorisusedin
industrial plants as well as in heating, venti-
lation and air-conditioning systems.
The actuator is a linear actuator which is
controlled by a three-step signal. It is suitable
forform-tattachmenttovariousSAMSON
valve series, depending on the version with
or without fail-safe action.
Principle of operation
The synchronous motor is switched off by
torque switches in the end positions and in
case of overload. The force of the motor is
transmitted to the actuator stem over gearing
and ball screw drive.
3.1 Fail-safe action
TheType3374ElectricActuatorisavailable
with or without fail-safe action.
Type 3374-2x and Type 3374-3x Actuators
are able to perform a fail-safe action and
contain a spring assembly and an electro-
magnet. The actuator is moved by the force
of the spring to the fail-safe position when
theelectromagnetisde-energized.
The direction of action depends on the actu-
ator version and cannot be reversed.
Testing according to DINEN14597
TheType3374ElectricActuatorwithfail-
safe action "actuator stem extends" is tested
bytheGermantechnicalsurveillanceassoci-
ationTÜVaccordingtoDINEN14597in
combination with different SAMSON valves
(the register number is available on request).
3.2 Versions
TheType3374Actuatorisoptionallyavail-
able with either integrated yoke (see
Fig.3-1)orusinganM30x1.5ringnut(see
Fig.3-2)includingthenecessarystemcon-
necting parts.
Fig.3-1: Construction with integrated yoke
(formB)
Fig.3-2: Construction for mounting with ring
nut (formA)