Ransburg MMA-303 Direct_Ind Charge Atomizer A12870 - Manual (Page 55)

MMA-303 Direct/Indirect Charge - Operation
LN-9269-11.3 52
FLUID VALVE CONTROL (Trigger,
Dump, and Solvent)
!
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 spin-
ning or when high voltage is turned on.
( See “Indirect and Direct Charge Circuit Dia-
gram” in the “Introduction” section.) The fluid
valves in the MMA-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 en-
able the fluid to flow through the bell paint pas-
sage 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 pres-
sure.
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 in-
side of the bell cup. The outside of the cup is
simultaneously cleaned by a nozzle mounted
on the shaping air ring and shroud. The sol-
vent 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 sol-
vent 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).
!
W A R N I N G
•
Never perform the interior/exterior cup
clean process with high voltage on.
•
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.
•
High voltage must be interlocked with the
solvent valve to prevent solvent spraying
while high voltage is on (direct charge on-
ly).
TURBINE SPEED
Turbine speed is determined by the input air
pressure/flow at the rear of the atomizer.
Turbine speed is intended to be closed loop
controlled using the fiber optic speed transmit-
ter, 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.)