Owner's manual

SECTION II. INSTALLATION
2-1. OVERVIEW. The power positioner is designed to
be installed upright. The floor stand is bolted to a
prepared horizontal foundation. A minimum of
45 psig to a maximum of 120 psig supply air pressure
is needed at mounting location. The power positioner
must be controlled by either an elect&J signal, when
using ao I/P signal converter, or by an air signal. All
wiring must conform to local and national codes.
2-2. SPECIAL INSTALLATION CONSIDERATIONS.
a. Foundation. The power positioner’s torque is
transmitted to operating arm of device being
positioned. This torque is also transferred to
power positioner’s mass aad it’s foundation. The
foundation must be designed to handle the torque
produced to keep power positioner stationary.
Refer to paragraph 2-3 for detailed foundation
requirements.
b. Supply Air. A supply air pressure of 45 psig to
23.
120 psig, minimum of 1 scfm, is required Supply
air must be free of oil and water to prevent pilot
valve sticking.
c. Linkage Design. Final control components play
a large part ia a control system. Special
characteristics of device being controlled affect
system response and must be regarded in design
and setup of a power positioning system.
Control valves and damper drives regularly allow
large flow rate. changes, compared to valve
movement, near the closed position. Smaller flow
rate changes, compared to valve movement, occur
near the fully open position. In normal damper
application, there may be no flow rate changes
after damper has reached 70% open. This
characteristic is represented by the following
equation:
Flow = k (Position)*
k = Constant
This equation means that flow is proportional to
the square of valve position. As damper or valve
opens, the. rate at which flow changes per valve
position is reduced. As valve or damper closes,
the rate at which flow changes per valve position
is increased. The coostant is a number that allows
the equation to work for different flow control
devices.
Conduct flow tests before attempting to liiit
damper opening. Testing is necessary to confm
actual damper characteristics and to make sore
control response is proportionate to input signal
throughout the flow range. When installing a new
paver positioning system, take care to properly
design the system for linkage size and action. In
a properly designed system, a percentage change
in control signal produces the same percentage
change in flow rate. Refer to paragraph 2-6 for
detailed information on design aad installation of
a liiearized control action power positioning
system.
POWER POSITIONER MOUNTING
INSTRUCTIONS.
a. Working Clearance Requirements. Make sure
area is clear of obstructions that will interfere
with powerpositioner operation and maintenance.
For standard unit, allow ao open area of 22
inches (vertically from foundation) by 16 inches
(side to side) by 28 inches (front to back). This
will allow for removal of dust cover, maioten-
axe, and full travel of operating lever. For
extended cover unit, allow aa additional 4 inches
vertically (26 inches from foundation) for
increased space requirements of thii power
positioner (Figare 2-l).
b. Location Selection.
1. Select location for power positioner as near
to the device b&g controlled as possible,
making sure necessary clearance for
operation and maintenance, as specified in
paragraph 2-3a, is available.
2. Use Specifications for Model PP405TR
Power Positioner, Table l-2, to make sure
environmental conditions are suitable for the
power positioner.