I inspect a lot of pulleys throughout my days. This one has popped up a couple of times over the past 6 months.
End shell failure on a conveyor pulley. I have been testing a clients pulleys for the past 6 months, in this time he has had two pulleys fail with the end shell crakingapart the welds. The client believed that this has just been bad luck and that we could not posibly have detected it. 5 years ago I would have just accepted this but I got a little curious and had another look at the data and the reports that were issued. This was when I recognised that the 1 X RPM that I had reported on in the report as a possible loose piece of lagging could have probably been the sound of the end plate & the shell impacting as it came into the load zone. On recovery of the broken pieces of pulley the bearings were assessed and there were no defects evident throughout.
Since this failure I have endeavoured to look for similar evidence throughout the conveyor system. Last night at about 10pm I discovered another pulley with the same features , the mine is currently removing this pulley from service and we will have a chance to inspect and measure the crack length. I will try and attach photos at a later date.

Things to beaware of when monitoring conveyor pulleys:
#1 Is the pulley covered with Rubber Lagging?
#2 If you think you have a bearing problem get some extra lube added. If it is related to the bearings the amplitude vibrations will decrease almost straight away.
#3 If the amplitude does not change with lubrication, further inspection of the pulley is required.
#4 Watch the belt come into & out of the pulley if it is bouncing on either side then this can put unwanted vibrations in the pulley.

These are just a couple of pointers that may help us all.

Hooch