Ransburg RMA Indirect A11600 - Manual (Page 37)

FLUID VALVE CONTROL
(Trigger, Dump, and Solvent)
(See "Figure 2 - Circuit Diagram" in the "Intro-duc-
tion" section.) The fluid valves in the RMA-303
are actuated by an air signal. The air pressure
must be greater than 70 psi (482.6 kPa) to assure
proper actuation of the valve. Applying air to the
valve actuator turns on the fluid or air for that valve.
The paint trigger valve controls the paint flow to
the bell. When actuated, paint flows through the
valve to the fluid tube, and into the rear of the
bell cup. The bell cup must be spinning at least
30,000 rpm when fluid is turned on to enable the
fluid to flow through the bell paint passage and
be atomized.
The dump valve controls the paint flow through the
dump line. When actuated, paint flow is directed
to the dump return line. This provides a method
of rapidly removing paint from the incoming line
for cleaning and/or color change. Normally, the
dump valve is not actuated at the same time as
the paint trigger valve since the trigger valve is
intended to cause the fluid to flow to the bell at
the prescribed input pressure.
The solvent valve controls the flow of cup wash
solvent. When actuated, solvent flows through a
seperate fluid tube passage and into the bell cup
. This provides cleaning of the inside of the bell
cup. The outside of the cup is simultaneously
cleaned by a nozzle mounted on the shaping air
ring and shroud. The solvent valve should never
be triggered at the same time as the paint trigger
valve to prevent solvent from flowing backward
into the paint line.
The cup wash air valve controls the flow of air. It
is recommended that this valve and the solvent
TURBINE SPEED
Turbine speed is determined by the input air pres-
sure/flow at the rear of the atomizer.
Turbine speed is intended to be closed loop
controlled using the fiber optic speed transmitter,
located on the turbine manifold. A speed input
to a remote speed controller, such as the Serial
Atomizer module, is required. (See "Speed and
Pressure" charts in the "Introduction" section.)
valve be controlled to create an air/solvent chop
sequence for superior internal and external cup
cleaning.
To color change the applicator, a solvent/air chop
must be provided through the main paint line. (See
"Figure 5 - Typical Installation" in the "Installation"
section.)
> The normal fluid flow range is 25-700 cc/
min. During a color change or when flush-
ing the system, higher flow rates may be
required. However, the maximum flow rate
through the bell cup must not exceed 700 cc/
min. to avoid solvent or paint from flooding
into the internal portion of the air bearing
motor assembly or front shroud.
W A R N I N G
!
> Never perform the interior/exterior cup
clean process with high voltage on (direct
charge only).
W A R N I N G
!
NOTE
> The bell rotational speed determines
the quality of atomization and can be
varied for various paint flow rates and
paint formulations. For optimum transfer
efficiency and spray pattern control, the
bell rotational speed should be set at
the minimum required to achieve proper
atomization. Excessive speed reduces
transfer efficiency!
RMA-303 Indirect Charge - Operation
Ransburg
33 LN-9252-06.4