tc series of tower cranes and tcp series tower cranes & placing boom are self-climbing tower cranes with an upper slewing mechanism, a trolley mechanism and a horizontal jib. tower crane series contain many types, such as tc5013, tc5015, tc5613, tc5023, tc5518, tc6020, tc7030, tcp5613/38, tcp5023/38, etc. using plc intelligent system in electric control system, stepless speed regulated and frequency altering in slewing mechanism, trolley mechanism and the hoisting mechanism also.... the hoisting mechanism double-speed coil winding rotor braked by eddy to alter speed or stepless speed regulated and frequency altering are used in the system. big strong drum with lebus groove. the slewing mechanism stepless speed regulated and frequency altering make starting and braking smoothly and position correctly and rapidly. the performance and operation is advanced in the world. the trolley mechanism stepless speed regulated and frequency altering. running with less impact and operating smoothly. control system plc intelligent control system can self-diagnose electric fault and give corresponding alarms with different sounds and lights. the main electric elements are using world-renowned products.