题目内容
如图所示,电阻R1=8Ω,电动机绕组电阻R0=2Ω,当电键K断开时,电阻R1消耗的电功率是2.88W;当电键闭合时,电阻R1消耗的电功率是2W,若电源的电动势为6V. 求:
(1)电源内阻
(2)电键闭合时,电动机输出的机械功率.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241158110772247.gif)
(1)电源内阻
(2)电键闭合时,电动机输出的机械功率.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241158110772247.gif)
(1)2Ω(2)1.5W
K断开时,电流
=0.6A
电源内阻
ε/I-R=2Ω
K闭合时,路端电压
=4V
电流
/R=0.5A总电流
ε
/
=1A
通过电动机的电流
=0.5A
电动机的机械功率
=1.5W
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811092351.gif)
电源内阻
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811108199.gif)
K闭合时,路端电压
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811123406.gif)
电流
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811123230.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811155241.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811155224.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811170185.gif)
通过电动机的电流
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811186268.gif)
电动机的机械功率
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115811201535.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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