Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 88)

4-6 Application Profiles for the SMC Dialog Plus Controller
Figure 4.5 Pump with Soft Start
Problem: A municipal water company was experiencing problems
with pump impellers being damaged. The damage
occurred during an across-the-line start and was caused
by the heavy shock to the impeller. The pumping station
motor was over 100 feet below ground, making repair
costly. For maintenance scheduling purposes, an elapsed
time meter measuring motor running time had to b
installed in the enclosure. Additional concerns were
energy consumption and frequent line failures, which
resulted in single phasing the motor.
Solution: The SMC Dialog Plus controller was installed, providing
a controlled acceleration of the motor. By decreasing the
torque during start-up, the shock to the impeller was
reduced. The SMC Dialog Plus controller’s built-in
Energy Saver feature was automatically activated
whenever the pump was lightly loaded for long periods of
time. Panel space was saved by employing the built-in
elapsed time meter. The SMC Dialog Plus controller’s
line diagnostics detected the pre-start and running single
phase condition and shut off the motor, thereby
protecting against motor damage.
Check Valve
Ground Level
Motor
Pump
480 Volts
30 HP