Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 122)

4-40 Application Profiles for the SMC Dialog Plus Controller
Figure 4.39 Ball Mill with Current Limit Start
Problem: An across-the-line starter was used to start the motor in a
ball mill application. The uncontrolled start was causing
damage to the gearbox, resulting in maintenance
downtime, as well as the potential for the loss of the
product (paint) being mixed. Line failures were a
frequent problem. The application required prestart and
running protection, as well as an elapsed time meter to
monitor the process time. Communication capability was
desired, and panel space was limited.
Solution: The SMC Dialog Plus controller was installed. It was
programmed for a 26-second current limit start, thereby
reducing the starting torque and the damage to th
gearbox. The metering feature of the SMC Dialog Plus
controller contained an elapsed time meter, which could
monitor the process time of the ball mill. Th
communications capabilities of the controller allowed the
process time to be communicated to the PLC, which
could remotely stop the ball mill. The line diagnostics
required in the application are standard in the SMC
Dialog Plus controller, and the built-in overload
protection saved panel space.
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480 Volts
150 HP
Loading Port
Drum
Substance
Ball Shot
Gearbox Motor