Introduction - Graco PRO AA5500SC Instructions And Parts List

How the PRO AA5500SC Electrostatic
Air-Assisted Airless Spray Gun Operates
(Refer to page 7)
WARNING
Remember, this is not an air spray gun; for your
safety be sure to read and follow the Warnings on
pages 3 to 5 and throughout the text of this
instruction manual.
The air-assisted airless spray gun combines airless
and air spraying concepts. The spray tip shapes the
fluid into a fan pattern, as does a conventional airless
spray tip. Air from the air cap further atomizes the fluid
and completes the atomization of the paint tails into
the pattern to produce a more uniform pattern. The
ability of the PRO AA5500 Electrostatic Spray Gun to
spray at higher fluid pressures provides the additional
power needed to atomize higher solids materials.
The standard gun is designed for use with reciproca-
tors and can be directly mounted to a one-half inch
rod. With additional brackets, the gun can be mounted
for robotic applications.
The gun functions are activated from a separate con-
troller that sends the appropriate signal to the actuat-
ing solenoids. Refer to Fig. 1 , page 8.
An optional fiber optic readout system can be installed
to monitor the gun's spraying voltage. A fiber optic
cable connected to the gun manifold carries the signal
from the gun to a remote ES display module. A battery
operated ES Display Module, P/N 189–762, can be
used, which will only display the gun's spraying volt-
age. The other available ES Display Module, P/N
224–117, will display the gun's spraying voltage and
current. Refer to Fig. 2 , page 9.

Introduction

Spraying
Applying a minimum of 50 psi (3.5 bar) air pressure to
the gun manifold's cylinder air fitting (CYL) will retract
the gun piston, which opens the air valves and a short
time later opens the fluid needle. This provides the
proper air lead and lag when triggering the gun. A
spring returns the piston when the cylinder air is shut
off.
Electrostatics
To operate the electrostatics, air pressure is applied to
the gun manifold's turbine air fitting (TA) through a
Graco electrically conductive air hose. The air enters
the manifold and is directed to the inlet of the power
supply turbine. The air spins the turbine, which then
provides electrical power to the internal high voltage
power supply. The fluid is charged as it passes the
gun's electrode. The charged fluid is attracted to the
nearest grounded object, wrapping around and evenly
coating all surfaces.
The turbine air is exhausted into the shroud and out
the back of the manifold. This helps keep contami-
nants out and keep the gun clean.
KV Switch
The gun's full high voltage setting is 85 kilovolts. The
gun's spraying voltage can be reduced by switching to
the low voltage setting for spraying in areas where too
much electrostatic wrap is not desirable. Applying a
minimum of 50 psi (3.5 bar) air pressure to the KV
switch air inlet (KV) will activate it and switch to the
lower voltage setting. The lower voltage is factory set
to 60 kilovolts at zero microamperes. This setting can
be adjusted from 45 to 80 kilovolts, as instructed on
page 37.The solenoid valve used to activate the KV
switch must bleed the air out of the line for the switch
to draw back to the higher voltage setting.