Hollow bore motor - help with selection

[joseph.lord]

I am looking for a small through hollow bore motor (not blind) that can take an 8, 10 or 12mm shaft. It is only driving a fan for air circulation so no need for precise speed or positional control. However it may need to go to a fairly high speed, say 1000RPM to stir the air properly. I am not familiar with motors but am struggling to find any that suit mechanically, or understand if they are suitable electrically. I have seen many small gimbal motors that look (mechanically) ideal but I don't think they work the way I need them to. Can any one help with what type I should search for or suggest any specific products/manufactures?

 

[waross]

I suspect that you will have to build it yourself.
You may be able to get a machine shop to overcome their skepticism and drill a through hole in a common type motor.

 

[waross]

Is the hole intended to supply air to the fan?
Fun with numbers;
Determine the rated cubic delivery of the selected fan.
Calculated the velocity needed to deliver that volume through an 8mm pipe.
Convert your answer to mach numbers.
Did I do this right?
For a volume of 1 cubic meter per minute through an 8 mm opening I get mach 0.97
That may be difficult to realize in the real world.

 

[waross]

Look at an inside-out fan motor.
These are readily available and are commonly used on large diameter ceiling fans. (Hint; Buy a ceiling fan and discard the fan blades.
In these motors, the stator is internal and the rotor is external.
The stator is suspended on a suitable rod or tube.
Consider suspending the stator with a suitable rod or tube.Then mount your fan on top of the rotor.
Now use a large diameter tube surrounding the support to supply air to your fan. The air supply tube may be as large as needed to deliver the desired volume of air at a reasonable velocity.