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                  軟啟動器如何實現輕載節能

                  2014/8/18 9:01:50點擊:

                  目前,交流感應電動機以其低成本、高可靠性和少維護等優點5,在各種工業領域中得到廣泛應用。但是,它在直接起動時,存在著兩個缺點:首先,它的起動電流可高達額定電流的5~7倍,這就要求電網裕量比較大,而且降低電氣控制設備的使用壽命,增加維護成本。
                  其次,起動轉矩可達正常轉矩的兩倍,這會對負載產生沖擊,增加傳動部件的磨損和額外的維護;谝陨显,產生了交流應電動機降壓起動設備。
                  傳統減壓起動方法有Y/△起動和自耦變壓器降壓兩種,每種都有各自的特點。電動機用Y/△起動時,在切換瞬間會出現很高的電流尖峰,會產生破壞性的動態轉矩,其引起的機械振動對電動機轉子、齒輪以及負載等都是非常有害的。自耦變壓器降壓起動設備體積龐大,成本高,而且還存在與負載匹配的電動機轉矩難控制等缺點。

                  籠型異步電機是感性負載,在運行中,定子線圈繞組中的電流滯后于電壓。如電機工作電壓不變,處于輕載時,功率因數低,處于重載時,功率因數高。軟起動器能實現在輕載時,通過降低電機端電壓,提高功率因數,減少電機的銅耗、鐵耗,達到輕載節能的目的;負載重時,則提高電機端電壓,確保電機正常運行。

                   

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