Siemens OpenAir GCA Series Technical Instructions page 11

OpenAir™ GCA Series Spring Return 160 lb-in Electronic Damper Actuator
Sizing
<62 lb-in (7 Nm)
>62 lb-in <160 lb-in
(>7 Nm <18 Nm)
>160 lb-in <320 lb-in
(>18 Nm <36 Nm)
Siemens Industry, Inc.
The type of actuator required depends on several factors.
1. Obtain damper torque ratings (ft-lb/ft
manufacturer.
2. Determine the area of the damper.
3. Calculate the total torque required to move the damper:
Total Torque =
1
Safety Factor: When calculating the total torque required, a safety factor
should be included for unaccountable variables such as slight misalignments,
aging of the damper, etc. A suggested safety factor is 0.80.
4. Select the actuator type using Table 2.
NOTE:
Mechanically coupled actuators must all be of the exact same type
except for the dual auxiliary switches and feedback potentiometer
options. Make sure to use the correct tandem-mounting bracket. See
Table 2.
Total Torque
GMA
GCA
ASK73.2U*: Tandem mounting bracket with any
combination of two GCA16x (standard 0 to 10 Vdc
modulating control) actuators mounted on the same
side of the damper shaft.
ASK73.1*: Tandem mounting bracket for two GCA 2-
position and floating control actuators that are mounted
on the same side of the damper shaft.
NOTE:
*Tandem application tested for up to four actuators. Each bracket mounts two actuators.
2
or Nm/m
×
Torque Rating Damper
1
SF
Table 2.
Sizing
Actuator
For applications requiring single damper
shaft operation by up to four GCA
modulating control signal actuators
mounted on each side of the damper shaft,
use the GCA15x Series Actuator with
Master/Slave mode operation selected. See
Figure 22 for master/slave DIP switch
settings, and Figure 27 for wiring of this
configuration.
Technical Instructions
Document No. 155-173P25
2
) from the damper
Area
May 19, 2014
Page 11