SKF Poly-V belts: PJ, PK, PL and PM profiles

In PHG 3PJ330, the 3 is the number of ribs, PJ is the profile and 330 is the length. PHG 6PK1000 has six ribs of PK profile. The profile defines the rib spacing and the belt height: PJ is the smallest of these, followed by PK, PL and PM, as in PHG 8PL2705 and PHG 10PM3010.

Two belts of the same profile and length with a different number of ribs are different references, because the width changes. If the removed belt has no marking, the profile is recognized by measuring the distance between two neighbouring ribs, and the ribs are counted. Write both down before measuring the length.

A Poly-V belt needs pulleys with grooves of the same profile. The number of ribs on the belt can be equal to or lower than the number of grooves on the pulley, never higher: a rib left outside breaks and takes the rest with it. Alignment between pulleys is more demanding than with a V-belt, because the belt is wide and thin.

It is common on machines with a single run that drives several accessories and uses an automatic tensioner. When the belt squeals or frays on one edge, check the tensioner and the idlers before blaming the belt. And if the ribs look glazed or cracked, look at the pulley grooves too, as they wear at the same rate.

Send us the complete PHG code and the quantity. Without a code, state how many ribs it has, the rib spacing, the measured length and the overall width. Add the number of grooves on the pulleys and the diameter of the smallest one. Tell us which machine it runs on, whether it has an automatic tensioner and whether the previous belt lasted as expected: that helps detect an alignment problem before repeating the order.