论文部分内容阅读
在三个互成120°角的线圈中,通以三相交流电就会产生旋转磁场。中学生在学习时感到理解有困难,一般是用实验演示来帮助理解。通常的旋转磁场演示仪是用三相交流电(或近似的三相交流电)来演示的,它能说明产生了旋转磁场,但不直观。为此我设计了一个用直流电产生模拟三相交流电的旋转磁场演示仪。实验原理如图1,圆P由电阻丝绕成(电阻约30Ω左右),沿直径装二只串联而成的电池组(可用二节1.5V的干电池或二只2V的蓄电池)。A,B,C为三个滑动接触头,它们彼此交120°角,可同步绕圆心O旋转。在旋转时U_(AO),U_(BO),U_(CO)(或U_(AB),U_(BC),U_(CA))即
In three coils of 120° angles each other, a three-phase alternating current will generate a rotating magnetic field. Middle school students find it difficult to understand when they are learning. They usually use experimental demonstrations to help them understand. The typical rotating magnetic field demonstrator is demonstrated by three-phase alternating current (or similar three-phase alternating current), which can explain that a rotating magnetic field is generated, but it is not intuitive. For this reason, I designed a rotating magnetic field demonstrator that uses a direct current to generate an analog three-phase AC. The experimental principle is shown in Fig. 1. The circle P is wound by a resistance wire (resistance is about 30 ohms), and two battery cells are connected in series along the diameter (two 1.5V dry cells or two 2V batteries). A, B, and C are three sliding contact heads that intersect each other at an angle of 120° and can rotate around the center O synchronously. U_(AO), U_(BO), U_(CO) (or U_(AB), U_(BC), U_(CA))