I have a project creating an epoxy based granite material.
The sphere packing density is quite high with aggregate sizes from 2 to 600 microns.
So that means I'm left with a very thick mix.
Plus the added complication of doing this in a vacuum.

Requirements:

I need to make a shaker/vibration unit (freq from 10 to 2000 Hz).
Using a motor to vibrate has been tried and it overheats... go figure :)!

Materials:
1 inch diam x 2 inch long Neodymium magnet.
Lots of magnet wire and even a coil winder.

Supposition:
It seems to me that I could mount magnet to base to vibrate, then create a coil around the magnet (with suitable separation) and drive that? I can dissipate the heat with a simple water jacket created from aluminum tubing and encapsulate that with an epoxy mixture designed to conduct heat which would be mounted to the rack in the chamber.

Question:
Is it possible to create a simple voice coil using a cylindrical magnet?.....FILTER
If so given almost 13000 Gauss, how do I calculate the coil parameters (windings,gauge,amps,voltage).

Or do I need to resort to using Axially magnetized magnet setup found in speakers?

Or perhaps there are other ideas.

25" at 2000Hz, lets use a middling mass of oh 100 _lbs.


Note: I'm not particularly good at this, I just happen to run a shaker motor for certian types of testing.
 
1/2000s is the total time to complete one cycle. (you dont say wether you need +/-0.25" so we'll go with total travel of .25" so +/-.125")

Dist= .021ft
TSD calcs: Time=.0005sec Speed(Avg)=41.7Ft/sec Dist=.021ft

using some basic guesses WTR max velocity and the shape of a sine wave we can say that max velocity is ~1.414*Avg Velocity....

So the mass must acclerate to 60ft/sec in .00025sec.
giving Acceleration as: 235855ft/sec^2 (or approximately 7000*G)

Requiring aproximately 2.35x10^7lbf*Ft/sec^2 or 5896ft-lb/sec or approximately 8000watts. If you can get better than 50% efficiency out of a voice coil I'd be reallly suprised. About a 120Hp or bigger motor should do the trick.

Now lets do the same math for 2Hz.
Time=0.5sec Speed(Avg)=0.042ft/sec Dist=0.021ft
Vmax=0.060ft/sec
Acceleration=.237552ft/sec^2
23.8lbf*ft/sec^2 or 5.938ft-lbf/sec or only around 8watts.

At 20 Hz (the official lowest threshold of heard sound) we should see around 80watts required.

Note: I dont really think that I am right with these calculations, however you can see what happens when you increase the frequency by steps of ten. The power required also goes up as quickly.

(I'm also an audio engineer, my biggest system has a power output btw 200-2000hz of ~1200watts, the speaker cones dont move anywhere near 0.25", Heck I dont think the 1500watts btw 60-200Hz even get that much movement, the 1400watts at 35-80Hz just might, but they're not horn loaded so they arn't pushing 100lbm back and forth.)

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