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A non-typical application for our
MCNC180A controller as a custom application, is it's use to
control this Electric Overhead Traveling Crane.
The primary use of the machine is
to perform lifting & precision placement of solid-fuel
booster-rocket- motors in a production, "cast-cure"
facility. The machine is rated at 220tons capacity, has 5 motions
available (hoist1/trolley1; hoist2/trolley2; bridge). The machine
operates in large dimensions (155ft span x 150ft lift x 550ft
bridge-travel) & yet can position each hook to an accuracy of
+/- ¼" in 3-dimensional space. The rocket-motors it handles
can be as large as 150ft in length.
The machine is used to lift the
rocket motor, rotate it to vertical & lower it into place
inside a "cureing-pit (oven) while the fuel is in it's liquid
state. After the fuel is "cured" (now "solid")
the internal cylindrical core is removed by converting the hoist
position control loop to a torque control loop in order to move
the core with controlled force. The hoist is then reverted back to
a position control loop, the finished rocket-motor is lifted,
rotated & placed in a shipping cradle for delivery. The system
was provided with an operator pendant for manual control & for
programming automatic control sequences as well as a serial
connection to a remotely located computer so the operations could
be controlled from a remote location with no people in the
facility. The availability of full CNC functionality in the
controller background allows appropriate operators to perform
unusual work & to modify the machine's operation when
necessary.
The machine was constructed by our
OEM customer using custom design as is appropriate for major
equipment, such as this crane (4 units were eventually
constructed). Standard metal wheels & rails were used &
standard industrial shunt-wound DC motors & SCR drives were
used in all 5-axes of motion. Alternatively, appropriately
designed flux-vector drives & AC motors could be used.
More Details in PDF
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