Fixed or Adjustible Center Variable Speed Pulley?


Pulleys make lifting heavy loads easier, and there are different types such as a fixed center or an adjustible center variable speed pulley. All types usually consist of some kind of rope, belt or chain and a wheel, which enables a person to hoist aloft a heavy load that they would not otherwise be able to.

As a supplier of industrial machinery parts, YB Components have a wide range of variable speed pulley products, such as replacement belts, wheels or sheaves, for both fixed center and adjustible center pulleys.

To help you find the exact part you may need, here we will look at the differences between a fixed center pulley and an adjustible center variable speed pulley.

Adjustible Center Variable Speed Pulley

With an adjustible center variable speed pulley, one shaft is always fixed while the other is moveable. Usually, the variable speed pulley will be mounted on the moveable shaft, with a fixed diameter sheave – or the rotating, grooved wheel – mounted on the fixed and stationary shaft.

The adjustability is achieved with a motor base that can be adjusted to create speed variation of the driven shaft, primarily by mechanically changing the center distance between the shafts. By increasing the center distance between the shafts, the pulley’s belt is drawn into to a smaller diameter within the pulley which then increases the drive ratio while reducing the driven shaft’s revolutions per minute (RPM).

Alternatively, decreasing the center distance enables the faces of the spring-loaded pulley to draw closer and contort the belt into a larger diameter.

Fixed Centre Variable Speed Pulley

With a fixed center variable speed pulley, the driving and the driven shafts are both stationary, or fixed. The driving shaft includes two pulleys whose pitch diameter can be adjusted, with one pulley manually controlled with an adjusting screw.

The driven pulley automatically conforms to the movement of the belt, with the variation in speed achieved by turning the adjusting screw. This screw adjustment causes the faces of the pulley to move either inwards or outwards which changes the pitch diameter where the belt rides through the pulley grooves during operation.

This change in pitch diameter creates an opposite change of the pitch diameter in the automatic pulley to compensate, with the driven shaft’s RPM adapting to the ratio change in the two pulleys’ pitch diameters.

Variable Speed Pulley Suppliers

Whether you need parts for a fixed or adjustible variable speed pulley, YB Components have years of experience sourcing every kind of spring-type or variable speed pulley and the various belts and chains they operate with. Available brands include Becker, Berges, Browning, Carlisle, Deepak, Deserti Meccanica, Lenze, Lovejoy Variable Speed Pulley and Miki Pulley. We also supply SIT pulleys and TB Woods, as well as variable speed pulleys for printing machines and Zero-Max Adjustable Speed Gearboxes.

If you require a fixed or an adjustible center variable speed pulley or particular parts, then contact YB Components who are the UK’s leading variable speed pulley suppliers in Yorkshire. We keep local stocks of all such parts and more ready to ship out fast and free all over the UK and the rest of the world.