Samson 3780 series, Mounting And Operating Instructions

Page: 14 / 76

2.1 Direct attachment to Type 3277
Actuator
For the selection of the required mounting
parts, refer to Tables 1, 2 and 3 (page 17).
When looking at the signal pressure connec-
tion or the switchover plate (Fig. 3) from the
top, the positioner must be attached to the
left side of the actuator. The arrow on the
black case cover (Fig. 12) should then point
towards the diaphragm chamber.
Exception: Control valves in which the plug
closes the seat area when the actuator stem
retracts. In this case, the positioner has to
be attached to the right side of the yoke, i.e.
with the arrow pointing away from the dia-
phragm chamber).
1. First screw the clamp (1.2) to the actua-
tor stem. Make sure the fastening screw
is located in the groove of the actuator
stem.
2. Screw the associated lever D1 or D2 to
the transmission lever of the positioner.
3. Fasten distance plate (15) with seal to-
wards the actuator yoke.
4. Place positioner on the plate (15) so
that the lever D1 or D2 will slide centri-
cally over the pin of the clamp (1.2).
Then screw on to distance plate (15).
5. Attach cover (16).
Note!
For quick-acting control valves (transit time
< 0.6 s), it is necessary to replace the filter
installed in the output pressure bore (Output
38) with a screw-in throttle (accessories spe-
cified in Table 3).
Actuator with 240, 350 and 700 cm
2
6. Check whether the tongue of the
seal (17) is aligned on the side of the
connection block such that the actuator
symbols for "Actuator stem extends" or
"Actuator stem retracts" match the actu-
ator design.
Otherwise, remove the three fixing
screws, remove the cover plate (18) and
reinsert the seal (17) turned by 180°.
When using an old connection block,
turn the switch plate (19) such that the
corresponding actuator symbol is
aligned with the arrow.
7. Place connection block with the associ-
ated sealing rings against the positioner
and the actuator yoke and screw it
tight, using the fastening screw.
For actuators with fail-safe action "actu-
ator stem retracts", additionally install
the ready-made signal pressure pipe
between the connection block and the
actuator.
Actuator with 120 cm
2
With Type 3277-5 Actuator with 120 cm 2
the signal pressure is transmitted via the
switchover plate to the diaphragm chamber.
For a rated travel of 7.5 mm, a brass
throttle has to be pressed into the seal lo-
cated in the signal pressure input on the ac-
tuator yoke. With 15 mm rated travel, this
is only required when the supply air press-
ure is higher than 4 bar.
6. Remove the vent plug on the back of the
positioner and close the side-located
signal pressure output (38) with the
plug from the accessory kit.
14
EB 8380-1 EN
Attachment to the control valve
All manuals and user guides at all-guides.com