140DAO85300C Quantum

140DAO85300C 

軟起動都是采用可控硅調(diào)制輸出。注意的是：可控硅是電流觸發(fā)型，變頻器是電壓觸發(fā)型，兩者電路是有差別的！電壓觸發(fā)型電路復(fù)雜，電流觸發(fā)型電路簡單。電流觸發(fā)型：電壓很低但電流較大，可達70-250毫安，只要驅(qū)動變壓器的頻寬和容量夠，次級加個二極管，就可以構(gòu)成電流型觸發(fā)電路，可控硅便可順利的導(dǎo)通和關(guān)斷。

這是硬件結(jié)構(gòu)，肉眼可見的。但這種電流驅(qū)動電路，維修時無法用指針萬用表直接觸發(fā)，監(jiān)視驅(qū)動脈沖判斷驅(qū)動電路的好壞。

作為工控硬件維修從業(yè)人員，也不要輕視軟啟動器，認為技術(shù)相對過于簡單，這樣想就錯了，特別時一些數(shù)字型的軟起動器。像AB，ABB，WEG這些品牌，控制電路就非常復(fù)雜，本身價值并不便宜。軟起動市場上應(yīng)用單位很廣泛，像船機，水廠，礦業(yè)這些單位，就有大把的軟起動器在使用。

維修軟起動其好處是，風險可控，不容易炸模塊。理論上不管什么品牌，原理都一樣。電路結(jié)構(gòu)可能不一樣，記住進線取樣，輸出取樣，溫度取樣，可控硅控制，這些都是具備電路。而且損壞多的也就是這些電路和配件。至于小信號控制電路，壞的幾率很少。開關(guān)電源部分壞的較多，但會修工控的從業(yè)人員，應(yīng)該都可以玩轉(zhuǎn)開關(guān)電源的。我自己的維修經(jīng)驗看，進口品牌，開關(guān)電源也很少壞，但進口品牌喜歡采用陶瓷貼片電容，那東西倒是容易短路。軟啟動維修中出現(xiàn)多的問題就是：可控硅壞，電源壞，輸入缺相，輸出缺相這幾類故障偏多。

多看說明書，試著用原理反推故障出現(xiàn)的可能，可以節(jié)省大把的維修時間。例如：輸出缺相，注意是不是沒帶電機（或者電機太?。?，軟起動的主要檢測是電流，電機太小達不到下限電流閾值，系統(tǒng)有可能判斷為輸出缺相（比如施耐德ATS48）,真的缺相了，那也不要總盯著輸出檢測電路，輸入同步信號沒有？沒有，肯定也報警?？煽毓枋且讚p件，但可控硅的損壞，不就是可控硅的質(zhì)量問題。軟起動需要建立在同步信號的基礎(chǔ)上，有的使用現(xiàn)場，進線電源波形失真非常嚴重，導(dǎo)致同步信號失真，就會造成可控硅驅(qū)動信號錯相損壞。

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