Theory #5


Array Theory #5


This is a theory of the potential arrangement of the magnets within the resin array on the pacman.  This is a theory I had thought of quite some time before Theory #4.

On the Forum, we have spoken many times about the concept of magnetic interaction varying with speed.  

Sean explained this quite nicely by suggesting a rotor which spun a PM past a piece of Mu Metal on every revolution.  That faster this rotor turns the less mechanical energy is required to cause it to pass the Mu Metal.  The same concept applies if the Mu Metal is replaced with a PM.

So we can say:  There is less magnetic interaction if you move a PM past another PM at speed than if you moved it slowly.

This effect is caused by LAG, which is another word for magnetic viscosity and is quantified using the term Coefficient of Magnetic Viscosity.  Lag is pretty much as it sounds, it takes the domains time to torque around to the direction of the influencing field. 

We may also think of the process of moving a PM past another PM as two transactions.

  • the travel from outside the PM to the center of the field or 'inside the PM'.
  • the travel from the center of the field to the outside.

With this background, let us consider a thought experiment...


The diagram below represents the configuration of the system before the small rotor rotates a PM across the Array to stop 'inside' the field of Neo #1.

The array is composed of only a single NEO at the bottom.  This NEO has its poles orientated such that it is in repulse mode with respect to the PM.

The PM is constrained so that it can only move in a vertical direction.

The Array is initially latched so it is held fixed in place.

 When the array is unlatched, it is constrained to move in a horizontal direction.

The PM must move down the path indicated at sufficient speed as to cause little magnetic interaction when it reaches the NEO.




At this point the PM has traveled from the top of the Array to the bottom, hitting the hardstop and stopping inside the field of the NEO.


NB.  Because the PM traveled fast, it caused little magnetic interaction with the NEO. (as per above). 

Consequently, it got inside the field 'cheaply', i.e. the main energy required was that to cause the speed. 

The coercivity, viscosity and permeability of the materials must be understood so that a balance may be struck between required speed and field strengths.





Immediately the PM stops inside the field of the NEO, the latch holding the array from moving is released.  The situation now is that of two magnetic fields in repulse mode resting very close to one another.  The result is the array is repelled, 'kicked' to the left.



With these two simple transactions, it seems that if you can get in cheap, with little magnetic interaction, then pretty much all the flux is still there for repulse.

eg, get in at 25% of what it would normally cost and come out with 100%.






There would be many timing issues with any arrangement such as this, consequently latches and ratchets etcetera would be required to manage the timing and orchestrate the movement.