To calculate how many turns of cable you will need on the drum for your cage and skip to move up and down by a certain distance (e.g., 500 meters), you primarily need the diameter of the drum and the length of cable movement required.

Calculation Method

1. Determine the circumference of the drum:

Circumference=π×Drum Diameter\text{Circumference}=\pi \times \text{Drum Diameter}Circumference=π×Drum Diameter

2. Calculate the number of turns needed to move the cage/skip by the desired length:

Number of Turns=Length of MovementCircumference\text{Number of Turns}=\frac{\text{Length of Movement}}{\text{Circumference}}Number of Turns=CircumferenceLength of Movement​

For example, if the cage and skip need to move 500 meters up and down, and the drum diameter is known, the calculation is:

Turns=500 mπ×Drum Diameter (in meters)\text{Turns}=\frac{500,\text{m}}{\pi \times \text{Drum Diameter (in meters)}}Turns=π×Drum Diameter (in meters)500m​

This gives the total number of drum rotations (turns) required to pay out or take in 500 meters of cable

Additional Considerations

• The cable diameter affects how many wraps fit per layer on the drum and the effective diameter of the drum as cable layers build up, which can slightly change the effective circumference per turn.
• For precise calculations involving multiple cable layers, you can calculate the length per layer considering cable diameter and drum width, summing lengths per layer to get total cable length on the drum

• Cable reel calculators online can help automate these calculations by inputting drum diameter, cable diameter, and required cable length

Summary

• Measure or know the drum diameter.
• Calculate drum circumference.
• Divide the required cable movement length by the drum circumference.
• The result is the number of turns of cable needed on the drum to move the cage and skip by that length.

This straightforward formula works well for single-layer winding and approximate calculations. For multi-layer winding or very precise needs, more detailed layer-by-layer calculations or software tools may be used.