Force required to drive the Trommel

[Slimshady]

TL;DR Summary

I have to calculate force required to drive the trommel? I dont know how will i calculate the kinetic coefficient of friction of bearings? can someone please guide me?

I have to calculate force required to drive the trommel? I don't know how will i calculate the kinetic coefficient of friction of bearings? can some please guide me?

 

[BvU]

Hello @Slimshady ,

$\qquad$ !​

You mention 'the trommel' as if everybody should know what you are talking about. We aren't all expert telepathics, so a bit more information might be helpful!

For comparison: A question like "how big an engine is needed to propel the ship" doesn't generate very useful answers either !

$\$

 

[john.phillip]

There are different designs for trommels, you definitely need to provide a sketch of your particular arrangement. For instance, there are trommels that just sit on tires or rollers, whilst others have a shaft running through the middle, with an electric motor in one end and several bearings along the shaft. They can be smaller than an oil drum and turned by hand, or as long as a couple of full sized containers. They also serve a multitude of applications, from mining to construction, or just trash segregation, which will affect the power required to drive the trommel.

You mentioned calculating a kinetic friction coefficient, but that is not something that is normally calculated, usually you either take a conservative number from a comprehensive tribology table, or you test your particular arrangement.

 

[sophiecentaur]

Summary:: I have to calculate force required to drive the trommel? I don't know how will i calculate the kinetic coefficient of friction of bearings? can someone please guide me?

I have to calculate force required to drive the trommel?

It depends on how accurate you want your answer to be. I suspect you might just be interested in a simple model in which you lift the load of 'stuff' by, say, the radius of the cylinder a number of times (assuming it's a dry / loose mix). I would think that bearing losses would be relatively insignificant.

So the power needed could be found from mass throughput per second times height lifted times number of times it's lifted. A first approximation would be to ignore the kinetic energy given to the stuff as it rotates around the axis.

I reckon that would give a good ball park figure for the motor power needed. Add at least 100% for work done on churning the material inside - such as liquid concrete- which would need work to be done on just stirring it up.

In the case of churning concrete, the engine power of a delivery truck motor could be known and also the mass of the mix and the rotation rate so you could check on how good my simple calculation is.

If a significant amount of stuff is separated from the main load on the way through (as in a seiving application) then that would be an added complication.