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You're the one whose missing here...

Posted by Steve Eddy on April 4, 2002 at 12:03:51

In Reply to: You are still missing something. posted by Danny on April 4, 2002 at 07:45:55:

You think "A magnetic isolation device is fundamentally no different than any other spring/mass isolation device. And the effectiveness of each ultimately depends on the fundamental resonant frequency and Q of the spring/mass combination."

It is still different Steve.

In a spring/mass system the spring is only carrying the load. The spring does not effectively perform the function of damping. The magnetic system can and does.

I'm sorry, but that doesn't change things one bit. You still have a spring/mass resonant system whose behavior is governed by the same laws of physics as every other spring/mass resonant system. The presence of any amount of damping doesn't change this fact whatsoever. EVERY spring/mass resonant system will have some measure of damping. Even those which use mechanical springs.

You need to get over this mental block of yours as to what constitutes a spring.

Case in point: Go out to your car and take off the shock absorbers and go for a ride. That will be a spring/mass system. By the way, you will be in for a bumpy ride.

Even WITH the shock absorbers, it's STILL A SPRING/MASS RESONANT SYSTEM. And you'll only be in for a bumpy ride if the frequency of the bumps fall within or below the natural resonant frequency of the leaf spring/car combination. Vibrations above this frequency will be attenuated more and more as their frequency increases. Just as with any other spring/mass isolation sytem.

When a shock absorber goes out on your car you can push down hard on the bumper and the car will bounce several times until coming back to a stop.

So what? All that does is demonstrate that the Q of the resonance is relatively high. And a high Q resonance is not necessarily a bad thing. Depening on where your natural resonance frequency is, a high Q resonance can actually provide GREATER isolation versus a more damped, lower Q resonance as damping reduces the slope of the rolloff of the low-pass mechanical filter you create with spring/mass resonant systems.

With a system using a mass (the weight of the component and top plate) and a magnetic field (the Levitator) the behavior is more like it is setting the mass on a piece of foam than a spring.

So what? You're still left with a spring/mass isolation system. Again, damping doesn't change this fact one bit.

There is a level of dampening not achieved with a spring. The magnetic field is more like an air shock. With lots of pressure in the shock it can be a bit bouncy. The Levitator is also a little bouncy with no load on it, yea just like a spring. However an air shock with the right amount of air pressure can provide a pretty smooth ride. Once loaded the Levitator is pretty smooth too.

Will you please get over this silly notion that a "spring" is limited to a coiled up piece of wire. I made it clear in my previous post that when I use the word "spring" as in "spring/mass" that I'm NOT referring to some literal mechanical spring. I'm beginning to think you're being intentionally dishonest here in order to continue your denial of the fact that the Levitator is a spring/mass isolation system.

Springs are also directly coupled. They are connected. Opposing magnets are not coupled, and not connected.

ONE LAST !@#$% TIME! I'M NOT REFERRING SPECIFICALLY TO ANY LITERAL MECHANICAL SPRING! I'M REFERRING TO THAT WHICH BEHAVES AND FUNCTIONS AS A SPRING, WHETHER IT BE MAGNETIC, PNEUMATIC, HYDRAULIC, MECHANICAL, OR OTHERWISE! NOW STOP MISREPRESENTING WHAT I HAVE BEEN SAYING!

Take two plates coupled with springs. Move the bottom plate forward quickly by .001". If this were happening continually it would be a lot of vibration. I guarantee you the top plate will follow that movement. There will be a delay in time, but not much, and the movement in distance will be exactly the same for the top and bottom plate.

Nonsense. The movement of the top plate will depend upon the frequency of the vibration with respect to the resonant frequency of the spring/mass combination of the spring and top plate. The top plate will move the greatest amount when the frequency of the vibration is the same as the resonant frequency. It will move less and less (i.e. greater isolation) as the frequency of the vibration increases above the system's resonant frequency.

This is how all spring/mass isolators function. This is also how the Levitator functions as it too is a spring/mass isolation system.

Due the same thing to the Levitator and the top plate may not move at all.

How much the top plate moves is governed by exactly the same physics as explained above. It will move the greatest distance when the vibration's frequency is the same as the resonant frequency of the spring/mass combination of the Levitator's magnetic springs and top plate. It will move less as the frequency of the vibration increases above this resonant frequency.

If and or when it does move forward to that distance that the bottom plate moved it will take a considerably longer time to float to that position.

How long it takes will be determined by the same physics that determine the time for every other spring/mass isolation system.

It is not acted upon with the same force that moved the bottom plate. Remember the Levitator does not have fixed coupling.

Nonsense. The forces acting between the top plate and bottom plate are no different simply because one force is a magnetic field and another is a mechanical spring. The same force applied by either will have the same effect.

With apologies to Mr. Ed:

A force is a force of course of course
But who ever heard of an invisible force?
That is of course
Unless the force
Is a strong magnetic field.

There are several thousandths of an inch of clearance in the pins that keep them aligned.

I'm sorry, no. It's NOT clearance that keeps them aligned. It's the inevitable CONTACT beween the top plate and the pins that keep them aligned. The small amount of clearance simply reduces the amount of wobbling versus a larger clearance.

And Steve, your assumption made in your last paragraph was out of line.

My only assumption was that you were NOT being fraudulent. If my assuming you were not being fraudulent was out of line, am I then to assume that you are being fraudulent?

se

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