TAC Pneumatic Products Catalog

800-0555
eries
Positive Positioning Relay
The N800-0555 is used with M556 (6 in. stroke),
M573 (3 in. stroke), and M574 (4 in. stroke) damper
actuators.
The N800-0555 is pilot-operated, providing
excellent response to small signal pressure
changes from the controller.
Pilot-operation also provides maximum resistance
to actuator shaft displacement caused by outside
force changes.
Features:
A built-in adjustable needle-valve permits setting the desired
rate of actuator movement, helpful in two ways:
• Various size actuators operated by the same control signal
can be made to operate at approximately the same rate of
movement, since the smaller actuators can be slowed to
match the rate of movements of larger actuators. One
example: Outdoor, return and relief dampers of
Air-Handling-Units, where the return damper is frequently
smaller, and has a smaller actuator.
• Some rapidly changing processes are easier to control if
the actuator moves slowly. Examples:
- Duct static-pressure control.
- Duct air-velocity control.
- Control of the mixed-air-temperature of air-handling
units, where the mixed-air-temperature changes instantly
as the dampers change position. Since no sensor
responds instantly, more stable control can be attained if
the dampers move slowly. This, in turn, may allow use of
a narrower controller throttling range.
Actuators may be ordered with positioners mounted. For
field-mounting, feedback arm and spring must be ordered
separately. Refer to Model Chart.
Model Chart
Model No. Description
N800-0555-BOX Positioner only.
N800-0555-P
N800-0555 Series
Positioner kit. Includes one positioner, one feedback arm, and 5 and 10 psi feedback springs for M556 (6 in.
stroke), M573 (3 in. stroke), and M574 (4 in. stroke).
F-27383-1 © Copyright 2006 TAC. All Rights Reserved. 67