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3. Center Wind RPM

A center wind mandrel acts like a pulley or sheave with a changing diameter. With each revolution, the diameter of the roll on the mandrel increases by twice the caliper.

The winding roll starts at the diameter of the core, and increases as the web is wound. We assume the web is delivered at a steady line speed. This implies that the mandrel RPM must start fast at the core and decrease in such a way as to match the line speed.

Enter a line speed, core diameter and maximum design diameter. We will calculate the mandrel RPM at core diameter and maximum roll diameter.

Enter Line Speed: 
Enter Core Diameter:  Enter Max Roll Diameter: 
    Core RPM   Max. Roll RPM

The optimum gear ratio for a 1750 RPM motor is based on the maximum speed at the core diameter.

Optimum Gear Ratio
Winding Roll1

By Clarence Klassen, KlassENgineering cklassen@klassen.on.ca