中文(简体)Since the section of bus duct跳離 is not specified in the national st海裡andard, the section o行相f bus duct marked with愛業 the same rated current of the same 兵中model is often different f高中rom that of different manufactu學大rers. There are several reasons for t村東his
(1) The cross section of the conve月數ntional sample is diffe黑章rent from that of the act影空ual product. Previous rou讀木tine test reports did not in河他dicate the section of the test作看ed bus duct. Since reduci睡不ng the section of bus 媽拿duct can reduce the cost and generate喝街 routine test report, la中從rge section bus duct is used as 生湖small section bus duct for rou鐘男tine test.
(2) Product parts and specifications ar能制e inconsistent. For the sample wit子物hout marked bus duct section, the笑兒 designer shall pay attent討為ion to prevent the manufacturer 到我from counterfeiting.
Bus duct is a conductor connec視開ting branch circuits of electr對通ical equipment. It is the carrier for c熱做ollecting and distrib計匠uting power, also known as bu工船s duct. Traditionally, the conduct放公or of the current ca厭習rrying branch in each distribut車電ion unit is usually called bus duct.他長 The function of bus duct i事吧s to collect, distribute an鐘師d transmit electric energy. 謝學During the operation of bus 唱答duct, a large amount of electric e呢看nergy passes through. When the bus城路 duct is short circu湖紙ited, it will produce great 老票thermal effect and electric effect. T得員herefore, it is very necessa不人ry to reasonably select the bus duc會美t material, section shap老這e and section area t黃街o meet the requirements o國藍f safe and economic operation.
The selection and applicat低店ion of bus duct under dif間來ferent environmental conditions shal坐司l consider the selection of bus duct樂子 of different types and materials. In a光媽ddition, for various bus ducts業外, the bus duct section sh下還all be selected according to the問少 long-term working current. Th得亮e short-time thermal stability and務到 dynamic stability of bus duct are草朋 verified under the condition of 鐵麗short-circuit curren老區t. Due to the resistance of wires an一日d the action of AC ammeter w低車hen multiple wires are 可體close, heat will be generated謝秒 when the bus duct p南身asses through the cu匠開rrent. The allowable heating 歌歌temperature for long又關-term operation of copper an雜劇d aluminum bare bus duct is 70 水內℃, but when there is a reliable tin coa秒路ting (such as ultrasonic tin plating)票月 on the contact surface, th相什e allowable temperature is i他外ncreased to 85 ℃. Limited我著 by the allowable temperatu花內re of continuous heat金劇ing, the long-term allowable current v門風alues of bus duct with different哥中 materials and sections are give子高n. When selecting the sect看鐵ion of bus duct, the actual long-ter木見m working current of bus duct (includin行志g overload exceeding half姐農 an hour) shall be less 志呢than the long-term allowable c購動urrent of bus duct of the selected紙時 section. When the aver明技age load of the year is large and th中爸e conductor and bus duct are large現金 (such as the bus duc化謝t of outdoor distribution equip醫機ment), the bus duct is usually selected朋好 according to the economic 人綠current density method. Econ購暗omic current density re會腦fers to the current flowin銀子g through the unit cros窗筆s-sectional area of bus duct煙用 under the condition of consider北你ing bus duct loss, annual mainten習廠ance cost and depreciation 我城cost of bus duct and auxi見大liary equipment. The section of bus慢水 duct can be obtained 水就by dividing the economic current den湖河sity by the long-term non overloa家術d working current. The section去雨 of bus duct selected by economi弟歌c current density method要北 is generally larger than that 生內selected by long-term wor話些king current method.
