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are resting on a high magnetic permeability
support plate that helps concentrate the
force fields. The best gap between the end
poles of the armature magnet and the stator
magnets appears to be about % of an inch.
As the armature north pole passes over a
magnet, it is repelled by the stator north
pole; and there's an attraction when the
north pole is passing over a space between
the stator magnets. The exact opposite is
of course true with respect to the armature
south pole. It is attracted when passing
over a stator magnet and repelled when
passing over a space.
The various magnetic forces that come
into play are extremely complex. The
leading (N) pole of the armature is repelled
by the north poles of the two adjacent mag-
nets. But, at the indicated position of the
armature magnet, these two repulsive
forces (which obviously work against each
other) are not identical; the stronger of the
two forces (double dashed line) overpow-
ers the other force and tends to move the
armature to the left. This left movement is
enhanced by the attraction force between
the armature north pole and the stator south
pole at the bottom of the space between the
stator magnets.
But that's not all! Let's see what is hap-
pening simultaneously at the other end (S)
of the armature magnet. The length of this
magnet (about 3% inches) is chosen, in
relation to the pairs of stator in magnets
plus the space between them, so that once
again the attraction/repulsion forces work
to move the armature magnet to the left. In
this case the armature pole (S) is attracted
by the north surfaces of the adjacent stator
magnets but, because of the critical arma-
ture dimensioning, more strongly by the
magnet (double solid line) that tends to
‘pull’ the armature to the left. It overpow-
ers the lesser ‘drag’ effect of the stator mag-
net to the right. Here also there is the
added advantage of, in this case, repulsion
force between the south pole of the arma-
ture and the south pole in the space
between the stator magnets.
The importance of correct dimensioning
of the armature magnet cannot be over-
emphasised. If it is either too long or too
short, it could achieve an undesirable equi-
librium condition that would stall move-
ment. The objective is to optimise all force
conditions to develop the greatest possible
off-balance condition, but always in the
same direction as the armature magnet
moves along the row of stator magnets.
However, if the armature is rotated 180
degrees and started at the opposite end of
the track, it would behave in exactly the
same manner except that it would, in this
example, move from left to right. Also
note that once the armature is in motion, it
has momentum that helps carry it into the
sphere of influence of the next pair of mag -
nets where it gets another push and pull,
and additional momentum.
Complex Forces. Some very complex
magnetic forces are obviously at play in
this deceptively simple magnetic system,
and at this time it is impossible to develop
a mathematical model of what actually
occurs. However, computer analysis of the
system, conducted by Professor William
of an instrument used to measure magnetic
field strengths over the stator magnets and
the intervening spaces. We shall call this
the 'zero' level, although there is a very tiny
gap between the probe and the tops of the
stator magnets. These measurements in
effect indicate what each pole of the arma-
ture magnet 'sees' below as it passes over
the stator magnets.
Next the probe is moved to a position
just beneath one of the armature poles, at
the top of the %-inch armature-to-stator air
gap. Another set of magnetic flux mea-
surements is made. The procedure is
repeated with the probe positioned just
beneath the other armature pole.
Now ‘instinct’ might suggest, and cor-
rectly so, that the flux measurements at the
top and bottom of the air gap will differ.
But if instinct also suggests that these dif-
ferences are pretty much the same at the
two armature pole positions, you would be
very much in error! In this particular
experiment the total magnetic flux amount-
ed to 30,700 gauss when the probe was
held at the zero level under the north pole
of the magnet, and a total of 28,700 gauss
when the probe was moved to the top of
the %-inch air gap. The difference between
these total measurements is 2,000 gauss.
Similar readings made at the air gap
between the south pole of the armature and
the stator magnets indicates a total flux at
zero level of 33,725 gauss, and 24,700
gauss at the top of the air gap. This time
the difference is a much larger 9,025 gauss,
or four and one half times greater than for
the north pole! Clearly, the magnetic force
conditions are far from identical at the two
ends of the armature magnet.
The Ultimate Motor. A motor based on
Johnson's findings would be of extremely
simple design compared to conventional
motors. As shown in the diagrams devel-
oped from Johnson's patent literature [not
included here], the stator/base unit would
contain a ring of spaced magnets backed by
a high magnetic permeability sleeve.
Three arcuate armature magnets would be
mounted in the armature which has a belt
groove for power transmission. The arma-
ture is supported on ball bearings on a shaft
that either screws or slides into the stator
unit. Speed control and start/stop action
would be achieved by the simple means of
moving the armature toward and away
from the stator section.
Note: To view and download Johnson's
patent, visit