The holding brake on a crane is designed to:

The holding brake on a crane is specifically designed to prevent motion when the crane is powered off. This is a crucial safety feature that ensures that a load remains stationary when the crane is not in operation, thus preventing accidental movement that could potentially lead to accidents or injuries on the job site.

In the context of crane operation, the holding brake works by applying a force to the system that effectively locks the crane's load in place when there is no power supplied. This gets particularly important during maintenance, setup, or in case of an emergency where power to the crane is lost. By maintaining the load's position, the holding brake protects both the integrity of the structure and the safety of personnel in the vicinity.

The other options focus on functions that are not the primary role of the holding brake. For example, enhancing speed, controlling load during lifting, and adjusting the angle of the crane arm relate more to the operational aspects or functionalities of the crane's movement and performance rather than the specific safety mechanism that the holding brake provides.