Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 15)

STC Starting Torque Controller 1-7
Applications (cont.)
Figure 1.9 Chair Elevator
Problem: A single-phase chain driven chair elevator was started
across-the-line. The starting torque caused the chair to
lurch during the start and occasionally caused chain
alignment problems.
Solution: An STC controller was installed to provide controlled
acceleration.This minimized the mechanical shock
encountered during across-the-line starting and reduced
alignment problems. It also allowed for regularly
scheduled preventive maintenance inspections, rather
than emergency maintenance repair.