Brochure

5
#2: Check the specifications
By knowing the ratings and specifications of the damper,
you'll be able to find the torque vector needed. Siemens
torque vector table is as follows:
Torque Formula:
Required Torque (LbIn) = Damper Area
*
Torque Factor
Required Torque (LbIn) =
*
Torque Factor
( )
EXAMPLE:
In this example, the damper physical properties are 36 inches by 36 inches with opposed blade damper and seals and
has a maximum air velocity of 2,000 ft/min. The next step is to find the required torque. To do that, multiply the torque factor
by the square footage of the damper.
Damper Width (In)
*
Damper Height (In)
In
2
Ft
2
144
( )
Lbln
Ft
2
Torque Vector Table
Torque Factor (Lb. In/Ft²)
Air Velocity (Ft/Min) < 1200 < 2500 < 3000
Damper Blade Style
Opposed Blade No Seals 3 4.5 6
Opposed Blade with Seals 6 7.5 10
Parallel Blade No Seals 4 6 8
Parallel Blade with Seals 8.5 10.5 14
Actuator Selection Checklist
1. Assess damper physical properties
2. Check the specifications

3. Understand application requirements
4. Adjust for mounting or accessories
Torque Requirements
Opposed Blade Dampers with Parallel Blade Dampers with
No Seals Low Leakage Seals No Seals Low Leakage Seals
Maximum Pressures of 2 in. wg or
Maximum Velocities of 1500 fpm
3 in-lb/ft
2
5 in-lb/ft
2
4 in-lb/ft
2
7 in-lb/ft
2
Maximum Pressures of 3 in. wg or
Maximum Velocities of 2500 fpm
4.5 in-lb/ft
2
7.5 in-lb/ft
2
6 in-lb/ft
2
10.5 in-lb/ft
2
Maximum Pressures of 4 in. wg or
Maximum Velocities of 3000 fpm
6 in-lb/ft
2
10 in-lb/ft
2
8 in-lb/ft
2
14 in-lb/ft
2