My laugh recently was on a soft starter that was tripping out, motor wouldn't even turn before it tripped. Never went to site, maintenance man called with questions. Figured out over the phone it was tripping on "overload" which was not motor overload but rather soft starter protecting itself from overloading current. I told him to check for mechanical issues. This is a high speed high inertia fan, runs faster than the driving motor, soft start needed so it don't go through so many belts. If you tighten belts enough so they don't slip when starting then it goes through more bearings.
When I talked to him later, he said they recently had a company replace some bearings and then balance the blower wheel. They never tightened the hub mounting it to shaft and blower slid to end of shaft and was rubbing on another component and it couldn't accelerate at all. :blink:
You would think that would have given them some issues with balancing it.
