Abstract : There are many types of lifting machinery, and their drive systems vary greatly, but their basic characteristics are similar. There are generally two methods for speed regulation of cranes: wound rotor series resistance speed regulation and frequency converter speed regulation. By comparing the two speed regulation methods, we can know the power loss of the two speed regulation methods, and then find a more energy-efficient and suitable speed regulation method. Keywords : lifting machinery, frequency conversion speed regulation, power loss 1 Load characteristics of lifting machinery 1.1 Mechanism categories of lifting machinery. The structures of different lifting machinery are very different, but generally speaking, their basic mechanism categories are as follows: hoisting mechanism, traveling mechanism, luffing mechanism, and slewing mechanism. (1) Hoisting mechanism, that is, the mechanism for raising or lowering the load, is the basic function of lifting machinery and is an indispensable part of any lifting machinery; (2) Traveling mechanism, that is, the mechanism for parallel movement of lifting machinery, most lifting machinery "walks" on a certain track; (3) Luffing mechanism, that is, the mechanism for extending or shortening the boom; (4) Slewing mechanism, that is, the mechanism for rotating and moving lifting machinery. 1.2 Load characteristics of lifting machinery. [b][align=center]For details, please click: Comparison of Two Speed ​​Control Methods for Lifting Machinery[/align][/b]