观察变频器起动的负荷曲线，可以发现它启动时基本没有冲击，电流从零开始，仅是随着转速增加而上升，不管怎样都不会超过额定电流。因此凝泵变频运行解决了电机启动时的大电流冲击问题，消除了大启动电流对电机、传动系统和主机的冲击应力，大大降低日常的维护保养费用。
（3）延长设备寿命
使用变频器可使电机转速变化沿凝泵的加减速特性曲线变化，没有应力负载作用于轴承上，延长了轴承的寿命。同时有关数据说明，机械寿命与转速的倒数成正比，降低凝泵转速可成倍地提高凝泵寿命，凝泵使用费用自然就降低了。
（4）降低噪音
凝结泵改用变频器后，降低水泵转速运行的同时，噪音大幅度地降低，当转速降低50%时，噪音可减少十几个绝对分贝。同时消除了停车和启动时的打滑和尖啸声，克服了由于调门线性度不好，调节品质差，引起管道锤击和共振，造成给水系统上水管道强烈震动的缺陷，凝结泵变频运行后，噪音、振动都大为减少，变化相当可观。
（5）其他许多变频调速改造前存在的问题都得到合理的解决。如使用阀门调节少了，精度提高了。出口的压力变小，对精处理过程的化学设备影响小了等等。
总之，大型汽轮发电机组凝泵推广使用变频调速器，可以大幅度降低厂用电率，减少发电成本，提高竞价上网的竞争能力。
5、我公司变频调速装置的优势
(1)功率单元电子式旁路
为了保证变频器和现场设备的正常运行，MLVERT系列高压变频器为用户提供了功率单元电子旁路功能，当单元故障时，IGBT上管导通，使其不影响整个系统的正常工作，使整个系统由原来的串联可靠性结构变成为并联可靠性结构。电子旁路示意图如下：
功率单元电子式旁路示意图
功率单元电子式旁路示意图
图4 功率单元电子式旁路示意图
（2）变频器带故障运行方式
当有功率单元故障时，变频器可通过线电压自动均衡技术，输出最大的功率而不至于跳机影响生产，用户可以根据设备的报警自行确定停机维修时间。design of this project, we found the logo! Although small, it has complete functions. Like PLC, it can completely replace the logic function of relay, and even realize the functions that ordinary relay is difficult to realize. Its control wiring is simple, which simplifies the production, maintenance and debugging of control system. If it is applied to mass-produced products, it can reduce the workload. It has convenient programming, powerful functions, less support, and the overall performance is more perfect than the original relay control, It is applicable to a wide range of processes, and it is convenient and fast to modify parameters and procedures in the process of use, which is conducive to the realization of standardized design.
Many years ago, when there were few PLC products on the market, we assembled "programmable controller" with electronic components. During this period, I used discrete components, small-scale IC and so on. Although the functions of such things can be realized, the biggest problem is that the reliability is not high.
There is one reason for this. Later, in my
