3
Installation and Operation
For Non-Spring Return Actuators
Preliminary Steps
1. Belimo actuators with NEMA 1 or NEMA 2 ratings should be mounted
indoors in a dry, relatively clean environment free from corrosive fumes.
If the actuator is mounted outdoors, a protective enclosure must be
used to shield the actuator.
2. For new construction work, order dampers with extended shafts.
Instruct the installing contractor to allow space for mounting the Belimo
actuator on the shaft.
For replacement of existing gear train actuators, there are
two options:
A. From a performance standpoint, it is best to mount the actuator directly
onto the damper shaft.
B. If the damper shaft is not accessible, mount the non-spring return
actuator with a ZG-NMA or ZG-GMA crankarm kit, and a mounting
bracket (ZG-100, ZG-101, ZG-103, ZG-104).
Determining Torque Loading and Actuator Sizing
Damper torque loadings, used in selecting the correct size actuator,
should be provided by the damper manufacturer. If this information is not
available, the following general selection guidelines can be used.
Damper Type
Torque Loading
Opposed blade, without edge seals, for non-
tight close-off applications
3 in-lb/sq. ft.
Parallel blade, without edge seals, for non-tight
close-off applications
4 in-lb/sq. ft.
Opposed blade, with edge seals, for tight close-
off applications
5 in-lb/sq. ft.
Parallel blade, with edge seals, for tight close-
off applications
7 in-lb/sq. ft.
The above torque loadings will work for most applications under 2” w.g.
static pressure or 1000 FPM face velocity. For applications between this
criteria and 3” w.g. or 2500 FPM, the torque loading should be increased
by a multiplier of 1.5. If the application calls for higher criteria up to 4”
w.g. or 3000 FPM, use a multiplier of 2.0.
Torque Loading Chart
2 3 4 5 6 7 8 9 10
140
120
100
80
60
40
20
10
Torque Loading (in-lb/sq. ft.)
Damper A
rea (sq
. f
t.)
