Its place in the roller mill
In a roller mill, motor power first goes by belts to the roll pulley and from there to the roll. The SPB-5 355 roll pulley is this main drive pulley: 355 mm in diameter and running five SPB belts. Its large diameter reduces motor speed to the speed the roll needs and spreads the high torque evenly across the belts.
Pulley diameter and roll speed
Roll speed is approximately motor rpm × (motor pulley diameter / roll pulley diameter). Keeping the 355 mm roll pulley fixed and using a 200, 190, 180 or 170 mm pulley on the motor side lets roll speed be set per passage. This flexibility makes it easier to use the same mill type on different passages.
How to recognise wear
- Belts sit deeper in the grooves than normal, with their tops below the pulley rim,
- Groove flanks are polished and “dished”,
- Belt sides are hardened and glazed, with squealing in operation,
- Belt tension needs frequent adjustment.
Worn grooves reduce the wedging action of the belt; the belt slips, heats up and roll speed drops under load.
Installation tips
Clean the key and hub surfaces when fitting the pulley to the shaft. On bushed versions, tighten the taper bush evenly in turn. Check alignment with the motor pulley; misalignment makes some of the five belts carry more load. Fit belts as a matched set and re-tension after the first run.
Altınbaşak SPB pulleys
We supply SPB-5 355 pulleys with a hub to suit your mill. Just send us the shaft diameter and mill model.
