V belt problem

[cokeguy]

We have 4700 rpm fan (with 4.5 inch sheave) driven by a 3500 20 HP rpm motor (6" sheave), using 3 3VX-800 belts. Without bothering anyone with actual calculations, does this combination seem reasonable, should it work OK, even at those speeds?

According to belt selection tables and guides (Carlisle,Tbwoods), and with our best interpretation of those documents, belt and pulley selection are OK, although I believe we are close to the limit in both sheave sizes and belt speeds. However, we still get belts jumping from the pulley or breaking, even after following all the troubleshooting guides in carlisle, for example...

Any comment will be very welcome. Thanks.

 

[diskullman]

Before you make any drastic changes, try using a banded v belt, a 3 rib 3vx800 belt.

Russell Giuliano