Overhead Crane Practice Test

How many wraps can an overhead crane with a lower limit device have left on the drum at its lowest point, according to A.S.M.E. B30.2?

1. Zero

2. One

3. Two

4. Three

The correct answer is: One

The guidelines set forth by A.S.M.E. B30.2 indicate that an overhead crane equipped with a lower limit device should have one wrap of rope left on the drum at its lowest position. This is to ensure that there is enough rope available to prevent potential accidents or failures when the crane is at its lowest operating point. Having one wrap remaining helps maintain the integrity of the rope and ensures that the load remains secure, allowing for safe operation. If there were zero wraps left, the risk of the rope slipping off the drum would increase significantly, leading to possible hazards. Similarly, having more than one wrap could result in unnecessary tension on the rope, affecting its longevity and safety. Therefore, the regulation emphasizes that leaving one wrap on the drum at its lowest point strikes the optimal balance for safe operation.