Technical Instructions
GBB/GIB Series Non-spring Return, 24 Vac, Modulating Control
Document Number 155-176P25
June 22, 2015
Page 10
Siemens Industry, Inc.
Sizing
The number of actuators required depends on several factors. To determine the quantity
of actuators required for the installation, do the following:
1. Obtain damper torque ratings (ft-lb/ft
2
or Nm/m
2
) from the damper manufacturer.
2. Determine the area of the damper.
3. Calculate the total torque required to move the damper:
Total Torque = Torque Rating × Damper Area
4. Select the total quantity of actuators required:
Number of actuators =
Total Damper Torque required
SF x Actuator Torque (Refer to Specifications)
1
1
Safety Factor: When calculating the number of actuators 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 (or 80% of the rated torque).
Mounting and
Installation
Figure 18. Acceptable NEMA 2
Positions.
Figure 19. Acceptable NEMA 2 Position
for Tandem Applications.
•
The direction of rotation switch must be set to match the clockwise or
counterclockwise rotation of the damper shaft. The factory setting is clockwise. See
Figure 14 for location on the actuator.
Figure 20. Direction of Rotation Switch.
•
The minimum damper drive shaft length is 3/4-inches (20 mm). The shaft length
determines whether the shaft adapter will be mounted on the front or back side of
the actuator.
•
See
Specifications
for minimum and maximum damper shaft dimensions.
•
The shaft adapter can be mounted on either side of the actuator. The direction of
rotation and shaft length determine how the shaft adapter will be mounted on the
actuator.
•
The position indicator can be mounted to show either the clockwise or
counterclockwise 0 to 90 scale.
•
The actuator is shipped from the factory with a 5° pre-load to ensure tight close off
of the damper.
•
The shaft adapter and mounting parts are shipped in a separate container with the
actuator.
•
Detailed mounting instructions are included with each actuator.
