EUP Lot 11 Motors Final Report – DRAFT –October 2007 56 of 109 From a study at a large chemical plant in Germany (Fa. Hüls AG) [39] the distribution of long-time failures was the following: (根據一份在德國的一家大型的化工廠,常會發生故障的原因如下:) - Bearing failures (76%) - Other mechanical parts (14%) - Stator Winding (6%) - Rotor Winding (4%) Typically, the repair process includes bearing replacement and if necessary rewinding. Provided that rewinding is done following good practice recommendations, no significant decrease in efficiency occurs [34]. (一般說來,修理程序包括了軸承的更換,甚至是繞組.假設需要重新繞線是實際依照建議來做的話, 不會有明顯效率衰退的情形發生) Of course, good practice recommendations are not always followed. Previous detailed studies identified an average 1.5 % decrease in efficiency per rewinding [26]. (的確,好的實際建議不會一直為大家所遵循,之前詳細的研究指出對於重新繞線的馬達,平均會減少1.5%的效率值.) A motor is normally repaired at least 2 times during its lifetime but this can occur up to 4 times [26]. (一台馬達在其使用壽命期限內通常都至少會有2次的維修記錄,最多到4次) Figure 2-13 allows the comparison between repair prices and new motor prices by power. It shows that for smaller motors the repair price exceeds the new motor price. (figure 2-13是將修理費用與新品馬達價格所做的比較.表中可看出,馬力數較小的的修理費用還超過新品馬達的價格) Figure 2-13 Comparison between repair prices and new motor prices [26] 2.5 Summary The developments in power electronics in the last decades allowed induction motors to achieve the same or even better torque/speed performance of DC motors in high demand applications, but with much higher reliability, leading to a shift away from DC solutions in industry. Nowadays, AC motors completely dominate motors sales representing 96% of all motors sold. The AC market is, in its turn, dominated by three-phase induction motors which represent 87% of AC motors sold. (在近十年對於電子(power electronics)的發展,使得感應馬達可以達到與DC馬達相同的扭力/速度表現,甚至還還更好, 符合對這些特性要求極高的一些設備需求, 使得工業逐漸脫離以直接電流的解決方式. 目前AC馬達完全主宰馬達市場的銷售, 佔有全部馬達銷售約96%. 接下來,AC市場又是由三相馬達所支配, 約佔AC馬達銷售的約87%.)