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目前,中小型塔式起重机在我国各地使用十分普遍。据塔机事故统计数据显示,中小型塔机事故总数比例占塔机行业事故总数比例的85%以上。造成塔机整体倾斜或断(折)臂的主要动作部位是起升机构。对于中小型塔机,起升驱动装置与电气控制系统基本都是采用传统绕线式电机转子串电阻调速方式与三速电机以轻载高速、重载低速方式来调速的硬启动方法,这样的控制技术使塔机在起升运行过程中经常出现电气故障,轻则损坏中间继电器和接触器,重则烧坏起升电机,同时无法控制塔司违规操作,造成塔机故障较多,故障的排除与处理非常麻烦,操作安装难度大,空中作业危险性大,维修时间长,给施工单位造成直接经济损失。采用变频控制技术在中小型塔机起升机构的应用对三相电压不稳定、电压低、不平衡、缺相、电机过载、变频器输出缺相与接地等故障变频器的自动保护功能都会自动停止起升电机运行;也有效防止塔机操作人员违规,操作实现零速制动,运行平稳无冲击,延长结构和传动件的寿命,从而减少塔机事故,使塔机整个起升系统操作灵活、安全、平稳、可靠、运行流畅。
At present, the use of small and medium-sized tower cranes in our country is very common. According to the tower crane accident statistics, the proportion of the total number of small and medium-sized tower crane accidents accounted for more than 85% of the total number of tower crane industry accidents. As a result of the tower crane as a whole tilt or broken (folding) arm is the main part of the lifting mechanism. For small and medium-sized tower crane, lifting drives and electrical control systems are basically using the traditional winding motor rotor resistor series speed control method and three-speed motor with light-load speed, heavy-duty low-speed way to start the hard drive method, This control technology makes the tower crane often appear in the lifting process of electrical failure, ranging from damage to the middle of the relay and contactor, heavy burnt lifting motor, at the same time can not control the tower division of illegal operations, resulting in more failure tower crane, Fault troubleshooting and handling is very troublesome, difficult operation and installation, air operations, dangerous, long maintenance time, causing direct economic losses to the construction unit. The application of frequency conversion control technology in small and medium-sized tower crane lifting mechanism Three-phase voltage instability, low voltage, unbalance, phase loss, motor overload, inverter output phase loss and ground fault inverter automatic protection function will be automatically Stop lifting motor operation; also effectively prevent tower crane operator violations, the operation of zero-speed braking, smooth operation without impact, extending the life of the structure and transmission parts, thereby reducing tower crane accidents, the tower crane the entire lifting system operation flexibility , Safe, stable, reliable, smooth operation.