The performance of the basic working capacity of lifting machinery is the most important performance parameters of the weight and work level. (1) Lifting weight refers to the maximum weight allowed to be lifted under the specified working conditions, namely the rated lifting weight. In general, the lifting weight of a crane with an electromagnetic sucker (see lifting sucker) or grab should also include the weight of the electromagnetic sucker or grab. The lifting weight of the boom crane also includes the weight of the hook group. (2) The work level is the performance parameter reflecting the general working condition of lifting machinery, and is an important basis for the design and selection of lifting machinery. It is determined by the total number of working cycles and load state that the lifting machinery needs to complete during the required use period. The International Organization for Standardization (ISO) regulations will be lifting machinery work level divided into 8. In China, only eight classes are required for cranes, and there are no classes for light and small lifting equipment, lifts and overhead monorail systems. The working cycle is also an important parameter for lifting machinery with regular and repetitive operation procedures, such as the loading and unloading of ship's cargo on the wharf, the stacking crane for the overhead warehouse and the hopper elevator for the blast furnace. Work cycle refers to the time required to complete a work cycle, which depends on the speed of the mechanism and is related to the carrying distance. Productivity is also sometimes used as an important parameter for the cranes mentioned above, usually expressed in terms of the amount of lifting done per hour.