How many wraps must be left on a drum machine when the car or counterweight are landed?

When a car or counterweight is landed on a drum machine, it's essential to have at least one wrap of the hoisting cable remaining on the drum. This ensures that there is enough support and security for the system, preventing any unintended slippage or loosening of the cable, which could lead to dangerous conditions during operation.

Having one wrap allows the hoisting system to maintain tension, ensuring that the load is securely held in place. This practice is crucial for safety reasons, as it prevents the cable from unwinding, which might occur if there weren’t enough wraps on the drum, especially when load dynamics change during operation.

In contrast, not having any wraps could risk the car or counterweight descending unexpectedly. More than one wrap is generally not necessary, as it can lead to unnecessary wear on the cable and the drum mechanism. Therefore, the standard industry practice is to leave one wrap on the drum after landing to maintain safety and operational integrity.