Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 95)

Application Profiles for the SMC Dialog Plus Controller 4-13
Figure 4.12 Exhaust Fan with Soft Start
Problem: The belts on an exhaust fan were frequently breaking,
causing maintenance problems. In addition to the high
cost of the belts, the fan belt guard was cumbersome to
remove. The high starting torque from the motor was
major contributor to the belt wear. Also, remote starting
and stopping of the fan from a PLC was desired. Panel
space was limited, requiring a compact device.
Solution: The SMC Dialog Plus controller was installed as a
retrofit to the existing starter. The ramp time was set for
28 seconds, facilitating a smooth acceleration while
reducing the starting torque of the motor and minimizing
the mechanical shock to the belts. The SMC Dialog Plus
controller has communication capabilities built-in,
allowing for remote control via a PLC. It also has built-
in overload protection, which saved valuable panel space.
Exhaust Intake
Belts
Motor
480 Volts
60 HP