Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 89)

Application Profiles for the SMC Dialog Plus Controller 4-7
Figure 4.6 Pump with Pump Control Option
Problem: A municipal pump was utilizing a soft start controller
with soft stop to control the pump motor. The soft stop
was controlling the motor in an open loop fashion by
reducing the voltage to the motor. Because there was not
enough torque provided to the motor to drive the load, the
motor’s stall point was quickly reached. During the stop
mode, severe surges were causing pipe vibration and
breakage.
Solution: The SMC Dialog Plus controller with the Pump Control
option was installed. The Pump Control option removed
the surges by controlling the speed of the motor during
starting and stopping. The microprocessor inside the
SMC Dialog Plus controller analyzed the motor variables
and generated control commands to reduce the surges in
the system.
Intake
Pump Housing
Motor
Outlet
Check Valve
480 Volts
150 HP