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电动机的转速受制于什么因素初中物理第二册第十章,安装直流电动机模型的实验中,要求学生在安装好之后,进一步观察……,以及转速与电流强度之间的关系.原话是:利用变阻器改变通过线圈的电流强度,观察转子转动的速度怎样随着变化.(p231)笔者揣度书上的意思.大概是想让学生得到如下的结论:通过线圈的电流越大,线圈转得越快.然而,这个结论是错误的.因此,书上的提法也是欠妥的.根据电功率P=UI,电功率等予电压和电流强度的乘积,在电压一定时,功率跟电流强度
The rotational speed of the motor is subject to what factors secondary school physics Volume II Chapter 10, the experiment of installing a DC motor model, requires students to further observe after installation ..., and the relationship between speed and current intensity. The original words are: Use a varistor to change the intensity of the current through the coil and observe how the speed of rotation of the rotor changes. (p231) The author’s intention is to read the book. It is probably to make students conclude that the greater the current through the coil, the more the coil turns. Fast. However, this conclusion is wrong. Therefore, the reference in the book is also inadequate. According to the electric power P=UI, the product of the pre-voltage and current intensity such as electric power, when the voltage is constant, the power and current intensity