Ransburg MMA-570 Direct_Ind Charge Atomizer A13366 - Manual (Page 42)

W A R N I N G
!
FLUID VALVE CONTROL
(Trigger, Dump, and Solvent)
( See “Indirect and Direct Charge Circuit Diagram”
in the “Introduction” section.) The fluid valves in
the MMA-570 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. Ap-
plying 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 20,000 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 separate 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
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
”Direct and Indirect Charge Typical Installation” in
the “Installation” section).
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.)
W A R N I N G
!
† Danger of shock and/or personal injury
can occur. Proper grounding procedures
must be followed. Personnel must never
work around the turbine when the turbine is
spinning or when high voltage is turned on.
† Never perform the interior/exterior cup
clean process with high voltage on.
† The normal fluid flow range is 25-800
cc/min. During a color change or when
flushing the system, higher flow rates may
be required. However, the maximum flow
rate through the bell cup must not exceed
800 cc/min. to avoid solvent or paint from
flooding into the internal portion of the air
bearing motor assembly or front shroud.
† High voltage must be interlocked with
the solvent valve to prevent solvent spraying
while high voltage is on (direct charge only).
C A U T I O N !
† Bell cup must be rotating at least 20,000
rpm when fluid is triggered. Turning on fluid
without the bell cup spinning may flood the
turbine and cause damage to components.
Fluid flow and turbine rotation must have an
interlock in place.
MMA-570 Direct/Indirect Charge - Operation
Ransburg
LN-9279-13 39