Problem: The conveyor would surge ahead of where the controller thought it should be and the system would STOP.
Solution: There is a bellows coupling between the Servomotor and the Gear-Reducer. This coupling had actually torn such that only a ½” piece of metal connected the two ends.
When the Servomotor advanced, its position-sensor reported a 100° motion whilst the belt position sensors reported no-movement because the coupling had introduced a delay between when the motor moved and actually moved the belt.
Problems with the motor-gearbox occur frequently, the Maintenance Staff has the foresight to keep an entire assembly in the wings, although not everybody on the team has performed this task.
To remove the entire motor assembly, 1)the cables must be disconnected, 2)the four bolts securing it to the main machine must be removed and, let me digress here.
Technician “M” is observing the entire operation, watching Technician “A” applying the lever/ fulcrum concept between the main body and the motor assembly with an 18” pry-bar from every conceivable angle. Technician “A” then rummages through the industrially sized toolbox for something else. Not finding, he hurries away to the shop.
Technician “M” observes the keyway and key and “feels” for the setscrew hole on the bottom of the Through Drive Shaft asking Technician “B”, “Did you guys release the setscrew on the bottom?” The answer being “no”, he quickly loosens the screw and the entire assembly falls sideways on the Through Drive Shaft, ready to be removed.
Technician “A” returns with a four-foot pry bar.