Technical And Mechanical Design; Transmission Of Power; Kopplung; Fail Safe Function - Siemens Acvatix SAS Series Basic Documentation

Function principle
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4.4

Technical and mechanical design

4.4.1

Transmission of power

Incoming positioning signals are translated to positioning commands for the motor.
A gear train transmits the motor's positioning steps to the output stage. Here, the
translation from rotary to stroke movement takes place. Attached to the gear train
are the electrical and mechanical accessory items and the manual adjuster. With
the stroke actuators with fail safe function, the gear train also accommodates the
return spring.
4.4.2

Kopplung

SAS.., SAT..
Antriebsstössel und Ventilstössel stossen
aufeinander. Sie sind nicht fix miteinander
verbunden.
4.4.3

Fail safe function

The fail safe function works mechanically with a return spring and ensures the
protection of the plant. It guarantees the safe operation in uncontrolled operating
states.
In the event of a power failure, the actuator will return to its 0 % stroke position with
the help of the return spring, closing the valve. The Y positioning signal is not
valued.
Fail safe
Actuator
function
Actuator's stem
Active
retracts
1)
Spring return time increased slightly at low temperatures
Actuators SAS.., SAT.. for valves
Functions and control
Valve
Spring in valve
Valve closes
closes
Spring return At positioning
time time
1)
<8 s 15 s
1)
<14 s 30 s
1)
<28 s 120 s
CE1P4041en
2019-04-09