Balancing of rotating masses

[Liam_91]

Hi,

I have a shaft rotating at 1500 rpm. the two bearing supports at either end of the shaft, A and B, have reactions of 5kN and 3kN respectively. I need to add a single balancing mass at a point along the length of the shaft inorder to balance the shaft and hence make the bearing reactions zero.



The shaft is 2 meters long. The balancing mass is positioned at 180 degrees to the bearing supports and has to be centred 200 mm from the centre of the shaft.


Is the first step of the question to take moments about one of the bearing reactions?

Thanks :-)

 

[Valkarie]

Yes, the first step is to take moments about one of the bearing reactions. You need to calculate the moment of the 5kN reaction and the 3kN reaction and then equalize them by adding the balancing mass. The total moment created by the two bearing reactions should be equal to the moment created by the balancing mass.