Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 106)

4-24 Application Profiles for the SMC Dialog Plus Controller
Figure 4.23 Chiller with Soft Start
Problem: A belt-driven fan on a chiller was frequently breaking th
belt because of high starting torque. Excessive downtime
was incurred because the housing had to be removed to
replace the belt. A combination across-the-line starter
was being used to control the motor. Control panel spac
was limited. A device utilizing the same control voltage
and line voltage was required because there was no room
in the panel for a control circuit transformer.
Solution: The SMC Dialog Plus controller was installed as a
retrofit to the chiller. It was set for an 18-second soft start
to reduce the snap to the belts as a result of the high
starting torque. It also reduced belt “squealing”
previously experienced during start-up. Because the
SMC Dialog Plus controller can operate with 240 volt
control voltage and line voltage, a control circuit
transformer was not required. The built-in overload
protection on the SMC Dialog Plus controller further
reduced the panel space required. The customer was able
to retrofit the controller into the existing panel space.
~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~
Fan
Belts
Motor
Condenser
240 Volts
75 HP