Breakway Torque

[Kinsrow]

Can anyone show me how to estimate the breakaway torque of a direct driven cylinder with the radius of 5" and weight of 100 lbm on a metal to metal bearing surface. I can do it with experiment but I was wondering if there is a magic equation for it.

Thanks

 

[MintJulep]

As a rough first cut:

W * mu * R

Where W is your 100 pounds.

mu is friction for the bearing surface.

R is the bearing radius

 

[Kinsrow]

MintJulep,

Elaborate that a little bit please. From your equation, the weight of the cylinder is considered normal force?. If I have this much breakaway torque, how could my acceleration torque is much smaller?

Thanks

 

[israelkk]

Reduce the friction coefficient or reduce the supported cylinder radius to the minimum. 100lb is quite a small force and a quite small bearing can be used.

 

[Kinsrow]

Israelkk,

Sure.

I'm trying to size my motor and need it to find the "breakaway" torque ( from static friction I guess) value.

Thanks