xuechaoqun 发表于 2012-3-5 21:50 static/image/common/back.gif
算是可以算，只是你提供的条件参数不全啊，
要算就要先设定一些参数
假设：
不好意思，直接启动是没有问题的。
取电机7.5KW，额定扭矩产生的加速度约为3.6>0.33，直接驱动是没有问题的，不好意思！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
有个相似工况，原滚动摩擦系数是0.0002m，但是考虑工况中存在滑动摩擦的情况，系数放大至0.0008m,参考来自轧钢机械的夹送辊设计，建议参考这方面资料。工况也是输送托辊靠辊子滚动送料。
最终归结到滚动摩擦与滑动摩擦的区别问题。
p=安全系数*umg*v/效率，对吗
美国人讨论摩擦系数的贴子：
proejuan (Mechanical) 8 Feb 07 9:47
What is the coefficient of friction for calculate the pull force in a rail car?
civilperson (Structural) 8 Feb 07 10:55
Steel on steel ranges from: High of 0.78 to Low of 0.05.Use of sand box required on slippery surfaces such as leaves, oil, & ice.Use 0.25 for design purposes, (2% maximum grade).
wiktor (Structural) 14 Feb 07 15:41
Typically 0.005 i.e 5 lbs per 1000 lbs.You can find more details here:
https://atiam.train.army.mil/soldierPortal/atia/adlsc/view/public/7489-1/fm/4-01.41/chap10.htm#tab10-1
harrisj (Automotive) 8 Mar 07 10:38
At a mu of .005, a 100-ton locomotive will achieve a drawbar pull of 1000 lbf. That's not much of a train.
The loco won't even make it up a 0.5% grade on its own, let alone pull anything else up it.
Something wrong here. Civilperson's numbers look more realistic, although I've never come across as high as 0.78 before.
civilperson (Structural) 8 Mar 07 11:29
Two different questions have been answered in the above postings.The rolling resistance of a towed rail car is given as an average by witkor, the tractive effort as a drawbar pull by a locomotive is given by civilperson and harrisj.The Army Manual cited by witkor has both answers. The STE, (starting tractive effort), is given as 0.3 to 0.2 with .25 as a design value and the CTE,(continuous tractive effort), is half of the STE.
我觉得是否可以先用一个3KW的电机，试上8小时，再观察发热程度和实际较果，这样比算公式快多了。
货物被压成18个微观的小坑了吧？这就不能用那个摩擦系数了 再者 货物开始运动的时候有加速度启动阻力比运行阻力要大
机械这块计算好的东西部见的就正确，很多加工装备的误差 还有物体的误差 都会影响到的。我就碰到这样的问题
这个要算加速度，考虑电机负荷曲线等因素的。理论功率是平稳载荷的，动载或加载条件下和电机的允许负荷要有一个平衡过程
这个 问题 难嫩