On Jul 12, 2007, at 5:54 AM, Stiffler Scientific wrote:
Would it possible to arrange things such that the _net_ displacement
of the field is zero?
Harry
Well, you can attempt to balance out the forces. See Figs 1-3.
| | | |
| M1 | | M2 |
-------- --------
============= ============= ============= Shield
motion --->
-------- --------
o| C1 |o o| C2 |o
o| |o o| |o
Fig.1 - Partial cross section of shield concept
| | | |
| M1 | | M2 |
-------- --------
============= ============= =============
-------- --------
o| C1 |o o| C2 |o
o| |o o| |o
Fig.2 - Intermediate state of shield in motion
| | | |
| M1 | | M2 |
-------- --------
============= ============= =============
-------- --------
o| C1 |o o| C2 |o
o| |o o| |o
Fig.3 - Shield open to M2-C2 flux
The shield here is a rotor with gaps that rotate between magnets Mi,
and cores with coils Ci, which are arranged in a staggered fashion as
shown, such that the force of closing off one flux path is balanced
by the energy obtained opening a flux path. Having N magnet-core
stators and N+1 holes achieves this. The bigger N is, the more
balance that can be achieved.
However, there will still be losses due to core and magnet heating,
even if no power is drawn from the coils. Further, as soon as the
coils draw power, the motion of shield is retarded because the
energy from opening the flux hole is less.
Horace Heffner
http://www.mtaonline.net/~hheffner/
