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Introduction
How the PRO 5500sc Electrostatic Air Spray
Gun Operates (Refer to page 7)
The PRO 5500sc spray gun operates very similar to a
traditional air spray gun. The atomization and fan air
are emitted from the air cap (A). The atomization air
breaks up the fluid stream and controls the droplet
size. The fan air controls the shape and width of the
spray pattern. The fan and atomization air can be ad-
justed independently.
Operating the Spray Function
Applying a minimum of 50 psi (3.5 bar) air pressure to
the gun manifold’s cylinder air fitting (which is marked
“CYL”, see page 7) 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.
Operating the Electrostatics
To operate the electrostatics, air pressure is applied to
the gun manifold’s turbine air fitting (which is marked
“TA”, see page 7) through a Graco electrically con-
ductive air hose. The air enters the manifold and is
directed to the inlet of the power supply turbine (G).
The air spins the turbine, which then provides electrical
power to the internal high voltage power supply (H).
The fluid is charged by the spray gun electrode (J).
The charged fluid is attracted to the nearest grounded
object, wrapping around and evenly coating all sur-
faces.
The turbine air is exhausted into the shroud (D) and
out the back of the manifold through the fitting marked
“EXH”. The exhaust air helps keep contaminants out
and helps keep the gun clean.
Switching to the Higher or Lower
kV Setting
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 (which is marked “KV”, see page 7)
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 36. 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.
Gun Features and Options
The gun is designed for use with a reciprocator,
and it can be directly mounted to a one-half inch
rod. With additional brackets, the gun can be
mounted for robotic applications.
The gun is designed for quick-disconnect, which
enables the operator to quickly remove the spray
gun without disconnecting the fluid and air lines to
the gun.
The gun functions are activated from a separate
controller that sends the appropriate signal to the
actuating solenoids (K). See Fig. 1, page 8.
An optional fiber optic readout system can be
installed to monitor the gun’s spraying voltage. A
fiber optic cable (V) connected to the gun manifold
carries the signal from the gun to a remote ES
(electrostatic) display module. See Fig. 2, page 8.
An ES Display Module (R), P/N 224–117, is avail-
able and will display the gun’s spraying voltage and
current. A battery operated ES Display Module (S),
P/N 189–762, is also available; it displays the
gun’s spraying voltage only.