ETS NORD FDMA-PM Series, Manual

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RDT-43-0921
5
® NORD fire |
FDMA-PM
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2.2 Design with actuating mechanism
Design .40, .50
The dampers are equipped with Belimo actuating mechanisms with back spring and thermoelec-
tric actuating device, of range BF (hereinafter referred to only as the "actuating mechanism"). After
being connected to power supply AC/DC 24V or AC 230V, respectively, the actuating mechanism
moves the damper blade to "OPEN" operation position and at the same time pre-stretches its back
spring. While the actuating mechanism is under voltage, the damper blade is in the "OPEN" po-
sition and the back spring is pre-stretched. The time needed for full opening of the damper blade
from "CLOSED" position to "OPEN" position is 120 seconds at the maximum. if the power supply
to the actuating mechanism is cut off (due to loss of power supply or by pressing the reset button
on the BAT thermoelectric starting mechanism), the back spring will move the damper blade to
"CLOSED" failure position. The time of moving the blade from "OPEN" position to "CLOSED" po-
sition takes 20 seconds at the maximum. If the power supply is restored (the blade can be in any
position), the actuating mechanism starts to move the damper blade to "OPEN" position again.
A thermoelectrical starting mechanism BAT, which contains two thermal fuses Tf1 and Tf2, is a part
of the actuating mechanism. These fuses are activated when tempe72°C has been
exceeded (the fuse Tf1 when the temperature around the damper and the fuses Tf2 when the
temperature inside the air-conditioning piping has been exceeded). After the thermal fuse Tf1 or
Tf2 has been activated, the power supply is permanently and irreversibly cut off and the actuating
mechanism, by means of the pre-stretched spring, displaces the damper blade into the breakdown
position "CLOSED".
Signalisation of damper blade position "OPEN" and "CLOSE" is provided by two limit switches.
Fig. 8 Design .40, .50
Fig. 9 Actuating mechanism BELIMO BF 230-TN, BF 24-TN (-ST)
BAT
Actuating mechanism