air compressor problem

[john worrell]

i have a lowe's a/c and am having trouble keeping the pulley from moving out of alignment on the motor shaft. i have put lock tite on the two set screws and bent my allen wrench trying to tighten. any suggestions?

[David G Baker]

Change out the two set screws with hardened screws with roughed up area on the tips. I have aligned pulleys and marked the area on the motor shaft where the screws hit and drilled a recess in the motor shaft.
I would think that a pulley that drives a compressor would have a key-way cut in the motor shaft and a key between the pulley and the shaft. On some compressors there can be a load during start up that may cause stress on the screw tips.
You could change out the pulley with one the same size but with a larger holding screws.

[Gary Click]

John,

The problem is most likely clearance between the pulley bore and the shaft. If this is the case no amount of LockTite or stress on the setscrews will solve the problem, only slow it down. The excess clearance allows the pulley to wobble slightly about the key on each revolution causing the pulley to walk on the shaft.

The fix is to replace the pulley with a correctly fitting (read that as tight bump on with a mallet) pulley if the motor shaft is in good shape. If the motor shaft is undersize, worn tapered or damaged, a pulley fitted with a QD Hub can solve this problem.

Remember advice is worth what you pay for it and I haven't invoiced yet.

[warren kafitz]

Your can try two set screws in the same hole, the first one to hold the pulley on the shaft and the second one to get the first one tight.
Warren