A small local manufacturing plant doesn’t have its own maintenance shop, and you work for an industrial services firm that supplies maintenance services. The plant manager called your firm, saying one of its “main production lines is dead.”
When you arrive at the line, the production supervisor shows you that pressing the START button doesn’t cause anything to happen. The line just won’t run. Knowing the first thing to check is whether the system has power, you look around and notice some indicator lights are on.
What should you check next, and how do you check it?
The line may have one or more E-STOPS. These are special switches that do not reset by themselves; they lock open when activated. An E-STOP has a large, distinct “mushroom head” that’s easily slapped by an operator. Look for these in all possible locations, and note their status before resetting.
It’s possible that a normal OFF pushbutton was incorrectly used as an E-STOP, so look for any of those as well (they must be replaced with the correct switch). These don’t lock open, and if one is used in this application there may be a manual reset back at the controller for the motor.
