Samson 3374-10 - Limit Contacts; Mechanical Limit Contacts; Electronic Limit Contacts; Manual Override

EB 8331-4 EN 13
Design and principle of operation
3.2 Limit contacts
The actuator can be equipped with either
mechanical or electronic limit contacts to in-
uence the tasks of control equipment.
3.2.1 Mechanical limit con-
tacts
The two mechanical limit contacts can be ad-
justed independently from one another. They
are operated by mechanical pins. The instal
-
lation and adjustment of the mechanical limit
contacts is described in section6.1.
3.2.2 Electronic limit contacts
The two electronic limit contacts consist of re-
lays with changeover contacts. In contrast to
the mechanical limit contacts, the electronic
limit contacts no longer function after a power
supply failure. The relays are de-energized
and the contacts change to the idle state. The
retrotting and adjustment of the electronic
limit contacts is described in section9.8.
3.3 Manual override
There are two ways to manually move the
actuator stem:
− Manual override with 4mm hex wrench
− MAN operating mode to move the actu-
ator stem manually
3.3.1 Mechanical override
The mechanical manual override is only pos-
sible for actuators without fail-safe action. It
is performed by placing a 4mm hex wrench
on the red actuator shaft located at the side
of the housing. The hex wrench is included in
the scope of delivery. It is attached to the
bottom of the housing.
Î Do not operate the manual override
while the actuator is running and only
when the power supply is disconnected.
3.3.2 Moving the actuator
stem manually
First place the actuator into MAN mode to
move the actuator stem manually. The oper-
ation and selection of the operating mode
are described in section8.1 on page42.