觀(guān)察變頻器起動(dòng)的負荷曲線(xiàn)，可以發(fā)現它啟動(dòng)時(shí)基本沒(méi)有沖擊，電流從零開(kāi)始，僅是隨著(zhù)轉速增加而上升，不管怎樣都不會(huì )超過(guò)額定電流。因此凝泵變頻運行解決了電機啟動(dòng)時(shí)的大電流沖擊問(wèn)題，消除了大啟動(dòng)電流對電機、傳動(dòng)系統和主機的沖擊應力，大大降低日常的維護保養費用。
（3）延長(cháng)設備壽命
使用變頻器可使電機轉速變化沿凝泵的加減速特性曲線(xiàn)變化，沒(méi)有應力負載作用于軸承上，延長(cháng)了軸承的壽命。同時(shí)有關(guān)數據說(shuō)明，機械壽命與轉速的倒數成正比，降低凝泵轉速可成倍地提高凝泵壽命，凝泵使用費用自然就降低了。
（4）降低噪音
凝結泵改用變頻器后，降低水泵轉速運行的同時(shí)，噪音大幅度地降低，當轉速降低50%時(shí)，噪音可減少十幾個(gè)絕對分貝。同時(shí)消除了停車(chē)和啟動(dòng)時(shí)的打滑和尖嘯聲，克服了由于調門(mén)線(xiàn)性度不好，調節品質(zhì)差，引起管道錘擊和共振，造成給水系統上水管道強烈震動(dòng)的缺陷，凝結泵變頻運行后，噪音、振動(dòng)都大為減少，變化相當可觀(guān)。
（5）其他許多變頻調速改造前存在的問(wèn)題都得到合理的解決。如使用閥門(mén)調節少了，精度提高了。出口的壓力變小，對精處理過(guò)程的化學(xué)設備影響小了等等。
總之，大型汽輪發(fā)電機組凝泵推廣使用變頻調速器，可以大幅度降低廠(chǎng)用電率，減少發(fā)電成本，提高競價(jià)上網(wǎng)的競爭能力。
5、我公司變頻調速裝置的優(yōu)勢
(1)功率單元電子式旁路
為了保證變頻器和現場(chǎng)設備的正常運行，MLVERT系列高壓變頻器為用戶(hù)提供了功率單元電子旁路功能，當單元故障時(shí)，IGBT上管導通，使其不影響整個(gè)系統的正常工作，使整個(gè)系統由原來(lái)的串聯(lián)可靠性結構變成為并聯(lián)可靠性結構。電子旁路示意圖如下：
功率單元電子式旁路示意圖
功率單元電子式旁路示意圖
圖4 功率單元電子式旁路示意圖
（2）變頻器帶故障運行方式
當有功率單元故障時(shí)，變頻器可通過(guò)線(xiàn)電壓自動(dòng)均衡技術(shù)，輸出最大的功率而不至于跳機影響生產(chǎn)，用戶(hù)可以根據設備的報警自行確定停機維修時(shí)間。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
