Gyroscopic forces

[tomhakon]

I have a calculation problem I need some help with. I have a cooler fan which is rotating with a speed of 1000 rpm, the axis of rotation is horizontal. The whole cooler is also rotating with a speed of 1 rpm around a vertical axis. The fan is supported on one end only. I need to calculate gyroscopic forces on the bearing/axle, I suspect it is quite simple, but I have never done such a calculation before. Anyone who has?

Distance fan-bearing: 0,1 m
Moment of intertia, fan: 0,639 kgm2

 

[Tmoose]

Double posting makes it harder to answer, and find answers. Looks like a recent post in "Bearing design......."

 

[tomhakon]

You are right. After first writing the post in "bearing design", I copied to this forum since I thought it was more suitable. My plan was to delete the first post after copying it, but I couldn't find out how to do it. Can it be done?

 

[EnergyMix]

1) Is this a school assignment?
2) Did you do a Google (or other Internet search engine) search on the words "gyroscopic force formula?"
3) Did you know that if you had done #2, you would have had your answer several hours ago and you wouldn't have bothered posting here, much less posting twice.
4) Hint, does the moment of inertia times the angualar momentum ring a bell?

 

[zekeman]

Ty=Iw*d(Theta)/dt
gyroscopic torque about y axis
Now equate this to external torques including gravityinduced.
From equilibrium equation
Ty+bearing torque +mgx=0
you get your answer.


I moment of inertia of spinning assembly
w = angular velocity of fan
d(theta)/dt rate of precession rotation about z axis
Ty gyroscopic torque
x distance CM to bearings
mgx moment due to gravity

 

[zeusfaber]

And in answer to your final question, yes: Red flag your own post and explain that you put it in the wrong forum in the box that comes up. Management will delete the offending item without holding it against you.

A.

 

[zekeman]

zeusfaber,

FYI, it was I who redflagged my own post since I had no way of deleting it.