Variable Speed Drive

Variable Speed Drive

The SIT VARIO belts are used for high power transmission on variable speed drive systems.

Belt characteristics
  • Wide range of sections and lengths
  • Temperature: -30/+75 °C
  • Tensile members: Flexten® (similar performances to Aramid)
  • Compound: Chloroprene
  • Oil, ozone and abrasion resistance
Variable Speed Pulleys – VAR

The variable speed pulley is a well established drive; designed to give continuous speed variation at a comparative low cost. Unfortunately, it is well known that this design is subject to excessive flange wear due to the type of drive systems employed.

The hub is made from induction hardened steel, hard chrome plated and ground to give uninterrupted slide fit with flanges. Keys are not used with this application. Moving flanges give a wide contact area therefore eliminating uneven belt pressure. The pulley flanges are coupled by means of nylon (6,6) sleeve couplings to the outside of the flanges and by two flats machined on each end of the pulley hub. Two springs situated inside the nylon coupling give the desired pressure.


Fixed Pulleys

Fixed driven pulley have been specifically designed to be used with VAR pulleys. They are manufactured in grey cast iron (GG20 -GG25) and are treated with a black manganese phosphating process.