转载 电力英语知识文章 先收着 慢慢看精选.doc

转载 电力英语知识文章 先收着 慢慢看 交流电动机 ---- A.C. motor交流电动机 ---- ac.motor 交流电动机 ---- alternating current motor交流电动机 ---- alternation current motorElectrical Energy Transmission电能的传输⑴考虑 图 1-1 所显示出的状况。从网络A一联网B，电能流动的功率是：⑴Consider the situation shown in Figure1-1. The rate of electrical energy flow (power ) from network A to network B isp=viNetwork A ---i, v---Network B( Figure 1-1 Power transmission between two networks.) （图 1-1：2 个网络之间的电能传播）⑵Lowercase letters are used to indicate instantaneous values, that is, that p,v, and i may vary with time. High power levels require high voltage and current values. For a given value of current, higher power flows may be obtained by increasing the voltage, and vice versa. Unfortunately, the existing technology sets practical upper limits on allowable currents and voltages. ⑵其中，小写字母用来显示瞬时值, 即p、v ，并且i随时间变化。高功率要求高电压和电流值。对于给定的电流值，高功率的能量流动可以通过增加电压获得, 反之也如此。但是, 就目前存在的技术而言，实际中许可的电流和电压成了最高的限制。⑶What are the limiting factors for current? We fabricate power conductors using materials with high conductivity, appropriate mechanical characteristics, and that are economical: aluminum is the most common choice, with copper used for some applications. The current-carrying capacity of a conductor is related to its maximum allowable current density and its cross-sectional area:Imax= Jmax A ⑶电流的限制因素是什么呢？我们通过使用具有高导电性、合适的机械特性的材料来制造输电导体，而且这些材料要求最经济：铝是最普通的选择, 在一些应用中铜也被使用了。导体的输电能力与它的最大电流密度和载面积有关：Imax= Jmax A⑷The maximum current density Jmax is determined by the maximum conductor temperature that will not damage the conductor or its insulation system.⑸What are the limiting factors on voltage? The fundamental consideration is to provide electrical isolation (or insulation ) between adjacent parts that can conduct current-that is, to confine current to the paths through which it was intended to flow. When the voltage exceeds the breakdown strength for a given insulation system, undesirable conduction paths will be created and the system will be e