【正文】 調(diào)換新燈泡。 （ 2） 鎮(zhèn)流器損壞，調(diào)換新鎮(zhèn)流器。 高壓汞燈燈泡不亮 （ 1） 外殼漏氣或放電管漏鈉，調(diào)換新燈泡。 （ 3） 燈座接觸不良，調(diào)換新燈座。 高壓鈉燈燈泡啟動(dòng)性能差 （ 1） 放電管內(nèi)鈉氣變質(zhì)或燈管電極發(fā)射性能差，更換新燈泡。 導(dǎo)線(xiàn)對(duì)地放電 更換玻璃管 ，擦拭玻璃支持物表面積塵 霓虹燈變壓器瓷套管破損裂紋，閃絡(luò)放電及相間、相對(duì)地短路 瓷套管破損，裂紋嚴(yán)重時(shí)應(yīng)更換變壓器，以防止故障擴(kuò)大造成事故。 5 電路中性線(xiàn)斷線(xiàn)時(shí)的三相相電壓分析 由于三相四線(xiàn)制照明電路在運(yùn)行中受機(jī)械力、電磁力的作用和熱效應(yīng)、嚴(yán)重氧化等原因 ,可能造成相線(xiàn)、中性線(xiàn)和設(shè)備內(nèi)部等斷路故障 ,使設(shè)備不能正常運(yùn)行。 正常情況 如圖 1 所示純電阻電路 ,只要電源電壓三相對(duì)稱(chēng) ,盡管三相負(fù)荷不對(duì)稱(chēng) ,但因負(fù)荷中性點(diǎn) O 與電源的中性點(diǎn) N 直接連接 ,若中性點(diǎn)的阻抗忽略不計(jì) ,則 O 點(diǎn)與 N 點(diǎn)同電位 ,于百色 職業(yè)學(xué)院畢業(yè)論文 第 18 頁(yè)，共 24 頁(yè) 是三相負(fù)荷電壓仍然對(duì)稱(chēng)。 于是 ,三相負(fù)荷電壓降就等于三相電源電壓 ,三相負(fù)荷電壓降是對(duì)稱(chēng)的。 若負(fù)荷不對(duì)稱(chēng)時(shí) ,假設(shè)三相負(fù)荷電阻的關(guān)系為 : 23A B CR R R?? 則電流關(guān)系為 : 2BAII? ， 3CAII? 由于負(fù)荷是純電阻性負(fù)荷 ,其電流與電壓同相位。以電流 .AI 作為參考向量 ,則得中性線(xiàn)的電流為 : 百色 職業(yè)學(xué)院畢業(yè)論文 第 19 頁(yè)，共 24 頁(yè) 0 0 00. . . .. ..0 12 0 12 0. 150233CN A Bj j jAAAjAI I I II e I e I eIe?? ? ?? ? ?? 由上式可知 ,通過(guò)中性線(xiàn)的電流是負(fù)荷最小那一相電流的 3 ,在選擇負(fù)荷極端不平衡照明電路的中性線(xiàn)截面時(shí) ,必須考慮到通過(guò)中性線(xiàn)電流的大小 ,不宜過(guò)小。上式說(shuō)明 ,當(dāng)中性線(xiàn)電阻 ? 時(shí) ,A 相負(fù)荷電壓降比中性線(xiàn)阻抗為零時(shí)升高了 004 。 中性線(xiàn)斷路 由于某種原因中性線(xiàn)斷路 ,為維持三相電流的向量和等于零 ,負(fù)荷中性點(diǎn)必產(chǎn)生位移 ,如圖 2 所示。負(fù)荷小的那一相 ,負(fù)荷電壓降則升高 ,照明負(fù)荷亮度就會(huì)變亮些。從上面分析可以看出 ,中性線(xiàn)在 三相不對(duì)稱(chēng)負(fù)荷中的作用是保證三相負(fù)荷電壓降對(duì)稱(chēng)的基本條件。因此 ,中性線(xiàn)對(duì)三相不對(duì)稱(chēng)負(fù)荷能正常工作起著及其重要的作用 ,在使用中除了中性線(xiàn)不能裝設(shè)熔斷器外 ,還要保證其可靠性 ,才能保證三相不對(duì)稱(chēng)電路的單相負(fù)荷設(shè)備的安全及正常工作。三年來(lái)我們真心相待，和睦共處，不是兄弟勝是兄弟！正是一路上有你們我的求學(xué)生涯才不會(huì)感到孤獨(dú)，馬上就要各奔前程了，希望你們有好的前途，失敗不要灰心，你的背后還有 11 電氣 班這個(gè)大家庭！ 最后我要感謝我的父母，你們生我養(yǎng)我，縱有三世也無(wú)法回報(bào)你們，要離開(kāi)你們出去工作了，我在心里默默的祝福你們平安健康，我不會(huì)讓你們失望的，會(huì)好好工作回報(bào)社會(huì)的。 ll wait in the line for one hour to get a ticket, and another two hours at the site, to only see a tiny bit of the place due to the crowds. Last year, 428 million tourists traveled in China over the weeklong holiday in October. Traveling during this period is a matter that needs thorough preparation. If you are short on time to plan the uping Golden Week it may not be a bad idea to avoid some of the most crowded places for now. There is always a place so fascinating that everyone yearns for. Arxan is a place like this. The beauty of Arxan is everlasting regardless of the changing of four seasons. Bestowed by nature, its spectacular seasonal landscape and mountains are just beyond word. Arxan is a crucial destination for the remended travelling route, China Inner Mongolia Arxan — Hailar — Manzhouli. It is also the joint of the four prairies across the SinoMongolian border, where people gravitate towards the exotic atmosphere mixed with Chinese, Russian, and Mongolia elements. As a historic site for the Yitian Battle, Arxan still embodies the spirit of Genghis Khan. Walking into Arxan, you will be amazed by a kaleidoscope of geous colors all the year round the Spring azaleas blooming red in the snow, the Summer sea wavering blue in the breeze, the Autumn leaves painted in yellow covering volcanic traces, and the Winter woods shining white on the vast alpine snowscape. Hinggan League Arxan city is situated in the far eastern area of Inner Mongolia Autonomous Region. Its full name Haren Arxan means hot holy water in the Mongolian language. Arxan is a tourism city in the northern frontier with a blend of large forest, grand prairies, vast snowfield, heaven lake cluster, thermium, as well as volcanic cluster. It is a rare and unique ecotourism base filled with healthy sunshine, clean air and unspoiled green. Nestled close to the country39。s time for the wild fruits to ripe. The picturesque Arxan in Autumn is indeed a fairyland only exists in a dream that satisfies all your fantasies. If it rains heavily on Saturday night, some elderly Chinese will say it is because Zhinu, or the Weaving Maid, is crying on the day she met her husband Niulang, or the Cowherd, on the Milky Way. Most Chinese remember being told this romantic tragedy when they were children on Qixi, or the Seventh Night Festival, which falls on the seventh day of the seventh lunar month, which is usually in early August. This year it falls on Saturday, August 2. Folklore Story As the story goes, once there was a cowherd, Niulang, who lived with his elder brother and sisterinlaw. But she disliked and abused him, and the boy was forced to leave home with only an old cow for pany. The cow, however, was a former god who had violated imperial rules and was sent to earth in bovine form. One day the cow led Niulang to a lake where fairies took a bath on earth. Among them was Zhinu, the most beautiful fairy and a skilled seamstress. The two fell in love at first sight and were soon married. They had a son and daughter and their happy life was held up as an example for hundreds of years in China. Yet in the eyes of the Jade Emperor, the Supreme Deity in Taoism, marriage between a mortal and fairy was strictly forbidden. He ordered the heaven troop to catch Zhinu back. Niulang grew desperate when he discovered Zhinu had been taken back to heaven. Driven by Niulang39。 Festival. In this day, girls will throw a sewing needle into a bowl full of water on the night of Qixi as a test of embroidery skills. If the needle floats on top of the water instead of sinking, it proves the girl is a skilled embroiders. Single women also pray for finding a good husband in the future. And the newly married women pray to bee pregnant quickly. Tradition transformed The love story of Niulang and Zhinu, and the Qixi Festival have been handed down for generations. Yet these ancient traditions and customs are slowly dying out. Many modern Chinese, particularly youngsters, seem to know more about St Valentine39。s Day. More and more young Chinese people begin to celebrate this day in a very similar way as that in western countries. Fewer people than ever will gaze at the heavens on Saturday to pick out the two stars shining bright on either side of the Milky Way, that is, if people even know on which day Qixi falls. There are ready reminders dotted about, in the form of big ads saying Sales on Chinese Valenti