Samson 3277 Mounting And Operating Instructions page 4

Design and principle of operation
Loading pressure connection
Type 3277 Actuator (Fig. 3)
In the Type 3277 Actuator with fail-safe ac-
tion "Actuator stem extends", the loading
pressure is connected to the loading pres-
sure connection (11) at the side of the yoke
to fill the bottom diaphragm chamber which
causes the actuator stem (2) to move up-
wards. In an actuator with the fail-safe ac-
tion "Actuator stem retracts", the loading
pressure is connected the loading pressure
connection (4) to fill the top diaphragm
chamber which causes the actuator stem to
move downwards.
Type 3277-5 Actuator (Fig. 4)
In the Type 3277-5 Actuator, the loading
pressure is connected to a borehole either at
the left or right of the yoke. A switchover
plate (14, accessories) directs the air to one
of the diaphragm chambers, depending on
the fail-safe action of the actuator ("Actuator
stem extends" or "Actuator stem retracts"),
which is determined by how the plate is
aligned with the mark (14.4).
4
Turn the switchover plate to align the
symbol (14.3) for the appropriate
fail-safe action with the mark (14.4). See
Fig. 4, bottom left. The operating direc-
tion (>>) or (<>) of the positioner deter-
mines whether the left or right attach-
ment is to be used.
A connecting plate (accessories) is required
instead of the switchover plate if the actua-
tor is operated without a positioner. The
loading pressure is directly connected to the
loading pressure connection (14.8) of the
connecting plate to fill the diaphragm cham-
ber.
4
EB 8311 EN
4
Turn the connecting plate to align the
symbol (14.3) for the appropriate
fail-safe action "Actuator stem extends"
or "Actuator stem retracts" with the mark
(14.4). See Fig. 4, bottom right.
4
Make sure that the flat gasket of the con-
necting plate is correctly inserted.
4
The connecting plate has both NPT and
G threaded bores. Seal the bore not re-
quired with a rubber gasket and square
plug.
Accessories: The switchover plate or con-
necting plate must be ordered separately.
Please note that actuators with modification
index 01 e.g. 3277-531xxx20.01 (old =
.00) are equipped with new plates.
Old and new plates are not interchangeable.
Switch- New
over plate Old
New
Con-
Old: G thread
necting
plate
Old NPT thread
Note! The pneumatic actuators are designed
for a maximum supply pressure of 6 bar.
To prevent the actuator from being dam-
aged, do not let the supply pressure exceed
the upper spring range value by more than
3 bar when the actuator is used for
flow-switching service (on-off valve) with the
fail-safe position "Actuator stem retracts".
Label actuators that have a reduced supply
pressure with a sticker "max. supply pres-
sure limited to ... bar".
Note! Refer to the operating instructions of
the corresponding valve on how to mount
and remove the actuator from the valve.
In-
Order no.
dex
01 1400-6822
00 1400-6819
01
1400-6823
00
1400-6820
1400-6821
00