论文部分内容阅读
表征交流电的物理量有瞬时值、最大值、有效值和平均值,对这“四值”应加以区别对待,下面通过例题来说明它们的区别与应用. 一、瞬时值与最大值的理解交流电的瞬时值反映的是不同时刻交变电流的大小和方向,因此瞬时值应表示为时间t的函数式:i=lmsinωt(从中性面开始计时).交变电流的最大值反映的是交变电流大小的变化范围,当线圈平面与磁感线平行时,磁通量的变化率最大,所以此时电动势最大,其值为:Em=NBsω(注意此式与线圈的形状无关).
The physical quantity of alternating current is characterized by instantaneous value, maximum value, effective value and average value. The four values should be treated differently. The following examples illustrate the difference and application of them. First, the understanding of instantaneous value and maximum value of alternating current The instantaneous value reflects the magnitude and direction of the alternating current at different times, so the instantaneous value should be expressed as a function of time t: i=lmsinωt (counting from the neutral plane). The maximum value of the alternating current reflects the alternating current. The size of the range of changes, when the coil plane and the line of magnetic induction parallel, the maximum rate of change of the magnetic flux, so the maximum electromotive force at this time, its value is: Em = NBsω (note that this formula has nothing to do with the shape of the coil).