Traction hoists must use at least ___ hoisting ropes, and drum type hoists must use at least ___.

Traction hoists require at least three hoisting ropes to ensure safety and proper lifting capability. This design provides redundancy and stability, which are essential for handling heavy loads during operation. The use of multiple ropes helps distribute the load evenly and reduces the risk of failure that could occur if only one rope were used.

For drum type hoists, at least two hoisting ropes are necessary. This setup allows for adequate support and stabilization of the load being lifted. The two ropes work together to ensure that even if one rope experiences wear or some level of malfunction, the other rope can still support the load, thus enhancing safety during operation.

This combination of requirements is established to promote safety in lifting operations and to comply with established safety regulations, which dictate the minimum number of ropes for different types of hoisting equipment.