Mike Krzyzewski is really a famous coach of Dream Team. She has coached north america men's basketball team for some time, that's clinched numerous medals for his country. Following Londonfl jerseys supplyn Olympic was over, Krzyzewski told The Associated Press that this game will be his final one as national coach, a job he's held for seven years. He had left open the possibility of swomen nfl jerseystaying with the team beyond the London Games, when practice on Saturday said these will be his last Olympics.When asked if he was sure, Krzyzewski didn't hesitate before again saying, "yecheap nfl jerseys wholesales," this will be his last game "If we could win it, then it might be three major championships in a row, i always do not know when that has been done because we haven't usually won http://govoriotkrito.bg/libs/nflcn08.htmthe globe championships," Krzyzewski said. "It becomes an enormous thing for the program." Whatever, he's an awesome coach. His achievement are going to be remembered by the country.cheap nfl jerseys
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    高壓隔離開關(guān)故障分析

    2014/1/9 8:21:11      點擊:
    高壓隔離開關(guān) 在系統(tǒng)運行中隔離開關(guān)發(fā)生的缺陷和故障比較多,涉及到多方面的質(zhì)量問題。對安全運行威脅最大的是瓷瓶斷裂故障,其次是觸頭過熱、運動卡滯、機構(gòu)卡澀和分合閘不到位、瓷瓶閃絡(luò)等。
    a.瓷瓶斷裂故障。2005年,徐州電網(wǎng)發(fā)生了2次瓷瓶斷裂故障,一次是在運行操作中,一次是在施工接線過程中,斷裂處均在瓷瓶和法蘭的膠合處。瓷瓶斷裂既與產(chǎn)品質(zhì)量有關(guān),也與隔離開關(guān)的整體質(zhì)量及操作方法有關(guān)。瓷瓶在燒制過程中控制不當可能造成瓷件夾生、致密性不均以及水泥膠裝不良的問題,加之質(zhì)檢手段不嚴,造成個別質(zhì)量低劣的瓷瓶被組裝成產(chǎn)品后,投放到運行中對安全構(gòu)成極大威脅。操作人員在分合隔離開關(guān)時操作方法不當、用力過猛也容易造成瓷瓶損壞。此外,2005年和2004年還發(fā)生了8節(jié)500kVSOPLT型刀閘支持瓷瓶開裂缺陷。
    b.導(dǎo)電回路過熱。運行中常常發(fā)生導(dǎo)電回路異常發(fā)熱現(xiàn)象,多數(shù)是由于靜觸指壓緊彈簧疲勞、特性變壞,靜觸指單邊接觸以及長期運行接觸電阻增加而造成的。運行中由于靜觸指壓緊彈簧長期受壓縮,如果工作電流較大,溫升超過允許值,就會使其彈性變差,惡性循環(huán),最終造成燒損,這是造成觸頭發(fā)熱的主要原因。此外,觸頭鍍銀層工藝差、易磨損露銅,接觸面臟污,觸頭插入不夠、螺栓銹蝕造成線夾接觸面壓力降低等也是造成發(fā)熱的原因。
    c.機構(gòu)問題。機構(gòu)問題表現(xiàn)為操作失靈,如拒動或分合閘不到位,往往發(fā)生在倒閘操作時,影響系統(tǒng)的安全運行。由于機構(gòu)箱密封不好或銹蝕進水造成機構(gòu)銹蝕嚴重,潤滑干涸,操作阻力增大,在操作困難的同時,還會發(fā)生零部件損壞,如變速齒輪斷裂,連桿扭彎等。
    d.傳動困難。隔離開關(guān)的傳動系統(tǒng)銹蝕造成傳動阻力大,甚至出現(xiàn)拒分拒合,如在運行中曾出現(xiàn)底座軸承銹死、無法操作的情況,這是由于傳動部件的主軸銅套干澀、軸承臟污、黃油干涸造成的。
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