F-26742-2
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Copyright 2006 TAC All Rights Reserved.
7
Mounting
Mount the TAC DuraDrive Actuator directly on the damper shaft in locations that clear the
maximum dimensions of the actuator case and allow the actuator to be mounted flush to the
surface of the terminal box and perpendicular to the damper shaft.
Note: Some terminal boxes have sheet metal screw heads or other protrusions near the
damper shaft. In these cases, a spacer or shim may be added under the mounting tab of
the actuator to make the actuator perpendicular to the shaft.
Damper Actuator Sizing
Correct sizing of the actuator is necessary for proper control of dampers. The area of
damper that can be controlled by a given actuator is dependent upon the type of damper,
the quality of the damper, the pressure drop across the damper in the closed position, and
the velocity of the air flow through the damper. To obtain actual damper torque
requirements, contact the damper manufacturer.
Damper Shaft Sizing
Use the “Long Damper Shaft” mounting instructions if the damper shaft is at least 4-5/8"
(117 mm) long.
Use the “Short Damper Shaft” mounting instructions if the damper shaft is shorter than
4-5/8" or the area around the damper shaft is too narrow to allow standard mounting, as
described in the “Long Damper Shaft” mounting section. See Figure-4 for minimum shaft
length.
Caution:
The MA40-717X actuator is not designed to be used on aluminum damper
shafts, solid steel shafts smaller than 1/2" diameter round or 1/2" square, or hollow steel
shafts smaller than 3/4" round. The actuator can produce up to 450 in-lbs (51 N-m)
maximum stall torque, which could result in the actuator snapping off an aluminum damper
shaft or an improperly sized steel damper shaft. Refer to Table-2 for nominal damper shaft
sizes.
Table-2 Steel Damper Shaft Specifications.
Figure-4 Long Damper Shaft Dimensions.
Min. 4-5/8" (117 mm)
Damper Shaft Shape
Damper Shaft Type
O.D. (Nominal)
a
I.D. (Maximum)
Round
Solid bar
1/2" to 1"
0
Hollow tubing
3/4"
0.375
13/16"
0.683
27/32"
0.626
7/8"
0.805
15/16"
0.808
1"
0.930
Square
Solid bar
1/2" to 5/8"
0
a
Damper shaft sizes over 1/2" (13 mm) O.D. require AM-753 universal mounting clamps.
