Damper
Actuators
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©Copyright 2011 Dwyer Instruments, Inc.
Topics
Key Selling Features (DDA, DDC, DDB, DDD)
Applications
Questions
DDA
Direct Mounted
17-70 in-lb (2-8Nm)
Actuator Travel
Indicator
Magnetic Clutch
Overload Protection
DDA
Push Button Manual Override
Floating Control signal on the DDA
Life expectancy of 60,000 cycles
Adjustable angle of rotation up to 95 degrees
DDC
Direct Mounted
17-70 in-lb (2-8Nm)
Actuator Travel Indicator
Magnetic Clutch
Overload Protection
Push Button Manual
Override
DDC
Modulating 4-20mA or
0-10 VDC control
Position feedback signal
Life expectancy of
60,000 cycles
Adjustable angle of
rotation up to 95 degrees
DDA and DDC
DDB
Direct Mounted
Thru shaft design
88-265 in-lb (10-
30Nm)
Actuator Travel
Indicator
Magnetic Clutch
Overload Protection
DDB
Push Button Manual Override
Floating Control signal on the DDB
Life expectancy of 60,000 cycles
Adjustable angle of rotation up to 95 degrees
DDD
Direct Mounted
Thru shaft design
88-265 in-lb (10-
30Nm)
Actuator Travel
Indicator
Magnetic Clutch
Overload Protection
DDD
Push Button Manual
Override
Modulating 4-20mA or
0-10 VDC control
Position feedback signal.
Life expectancy of
60,000 cycles
Adjustable angle of
rotation up to 95 degrees
DDB and DDD
Applications
Damper Control in Building Automation
Systems
Air Handlers
VAV Boxes
VAV Boxes
A VAV (variable air volume)
box controls the air addition
to a room or zone depending
on temperature
A damper inside the VAV
box controls the airflow
A damper actuator
modulates the damper
according to temperature
VAV Box with Reheat
Application with an
actuator controlling
the damper and
giving position
feedback
VAV Box In a BAS System
Negative
Pressure Room
Has VAV Box
on air inlet
Bypass Dampers
A Bypass Damper is
a pressure relief valve
placed between the
supply and return
ducts of the forced
air duct work.
Bypass Dampers
As Zone dampers start closing,
the bypass damper will open
and divert some of the supply
air to the return.
This prevents a pressure
buildup in the supply duct
which can cause fan cavitation,
excessive air velocities, and
excessive zone damper blow-
by
Air Handlers
The air handler decides how much air to reuse,
bring in new, and exhaust in a building
Dampers control the airflow through the air
handler
Return Air from the building
Outside Air from outside the building
Exhaust Air from the building and exhausted to
outside
Questions
To order a free catalog or for more information contact;
Dwyer Instruments, Inc., P.O. Box 373,
Michigan City, IN., 46361
Telephone: (800) 872-9141 or (219) 879-8000
Fax: (219) 872-9057
Internet address: www.dwyer-inst.com
E-mail: [email protected]