Is the noise like a squealing noice or a bang?

If it is squealling then you are getting slippage on the drive and require more tension (or weight) in your take-up system. ■

I had a large drive pulley (3.4MW) and it had a "Clank" as opposed to a "Squeak"

The client refused to accept it, so one night I drilled a couple of holes in it and pumped it full of expanded polyeurethane.

Filled the holes with Pratley's Putty and after a lick of orange paint, all was well.

(Ran like that for years!)

Cheers

LSL Tekpro ■

Dear Graham,

Sounds like the internal thingamajig broke loose as they often do. Then they go rattling around bouncing between shaft and shell. Some attribute the thingama-jig to light stitch welding and incompatible deformation of shell to thin internal disks.

We prefer to omit thingamajigs in modern designs. They were used in ancient times to help form the cylindrical shape of the shell when proper shell rolling techniques were dubious.

The thingamajigs were also found to be a problem with shell failures. Not just poping lose, but, causing stress risers and crack initiation in shell as the failed from weld breaks.

Synonyms: dingus, doohickey, hickey, thingamabob, doodad (or thingumajig), thingummy, whatchamacallit, whatnot, whatsit (also whatsis or what-is-it) ■

But if something was loose inside: then surely it would rattle about all the time: not just under laden conditions? ■

Louispanjang,

True. The internal disk may not be fully broken, just part of the weld stitching has broken. As more load is applied, the broken sections register the shell deformation from bending and hoop strain with noisy rubbing.

Due to the high forces, it does not take much rubbing to create the squeak or squeal. The type of noise would be quite different from belt slip. Belt slip is a very high resonance compared with disk-to-shell rubbing. The internal disk is a clanck at the pulley rpm. So which noise is it?

I am not emphatic in stating this cause. The only evidence is another's interpretation. ■

Might be worth borrowing an endoscope, drilling a couple of holes and having a look around inside. Might see something ■