motor torque

[cgben]

I am building a display case, and I am needing to know what kind of motor I will need to use to rotate a 100 lbs object at about 4 rpm. I am unable to find any calculations.
Thanks
CGBEN

 

[rbulsara]

What is the size and shape of the object? A relatively light lump of metal shaped to move air (called fan blades/impreller) would require much more power than a solid disc!

 

[rbulsara]

Also refer to this link:

http://www.patchn.com/motorformula.htm

You will have to find the 'inertia' of the object or Wk^2 where W is the weight and k is radius of gyration, which is calculated by shape of the object.

 

[cbarn24050]

Hi, first you have to find the moment of inertia of your load, then you have to decide what angular acceleration you require, add in frictional losses. That should give you the power required.

 

[jbartos]

Suggestion: Visit

http://www.motorsanddrives.com/cowern/motorterms7.html

etc. for more info

 

[rshoultz]

1200 rpm AC motor with a 300:1 gearhead should cost you about $80. 2" or 3" frame should be large enough. Direct couple motor to the load. The friction of the gearing should dampen OK during startup. If not use a lossy coupler like a section of stiff hose and hose clamps.

 

[jbartos]

Suggestion to the original posting: Proceeding from the load side to the motor side leaves a wide choice for the motor selection. The choice would narrow down if there was posted preferred motor voltage, frequency, type of controls, etc.