I have decided to compile this Research Note as a diversion
from preparing a response to a U.S. Patent Examiner’s rejection
of my Patent Application Serial No. 08/579,991 which has a U.S.
filing date of 12/28/95.
The Examiner’s comment reads:

‘The applicant asserts that the motor receives more electrical power back than was input to the motor. The statement directly violates the Laws of Conservation of Energy. The applicant has provided a mathematical derivation as support for this claim. However, the equation is incomplete. It does not reflect any heat or resistance losses generated by the structure of the motor, nor does it show the reputed magnetocaloric cooling effects. Further proof and explanation is required to support this assertion.’

Now, to be strictly correct, I did not affirm in my
specification that ‘the motor receives more electrical power back
than was input to the motor’. I did, however, explain why it was
possible to take more electrical energy from an inductance than
had been supplied as electrical power input, but there really is
nothing clever or magical in that, because the process I referred
to involved pulling a magnet away from a soft iron core member
and that involves an input of mechanical work. Every dynamo that
incorporates a magnet generates electrical power output in that
way.

My real concern arises from the other comments by the
Examiner because that word ‘reputed’ implies that the Examiner is
unaware of what I mean by ‘magnetocaloric effects’.

I intend now to describe what I might term a ‘Magnetocaloric
Motor’ but stress that this motor is hypothetical and impractical
as a commercial proposition. It in no way corresponds with the
motor disclosure in my patent, but it does serve to educate those
who find it difficult to believe the principles of physics that
apply to the motor developments which I am pursuing. I stress
that the physics I use is standard physics which in no way
involves any breach of the law of energy conservation.

I want you to imagine a solid cylinder of a ferromagnetic
substance with a solenoidal winding wrapped around it. It is
positioned with its axis vertical and it has, underneath it, a
strong magnet held to it by its magnetic attraction. The magnet
is heavy and, if it were free from that magnetic hold, it would
fall under gravity. It could, for example, be part of a
reciprocating engine which supplies a drive torque to a flywheel
through a connecting rod and crank system.

Now, a ferromagnetic substance has a ‘Curie temperature’,
which is the temperature of transition at which it loses its
ferromagnetism and behaves as a normal metal to which that magnet
is not attracted.

My scheme is to supply heat as an energy input to my motor
and cause that cylinder to lose its ferromagnetic state. What
must then happen is that the magnet will fall from the top-dead
centre position to the bottom dead-centre position and turn the
flywheel and its shaft through 180 degrees. That delivers
mechanical work as output. Note that I could, if I wish, take
electrical power from that solenoid as the magnet falls. Indeed,
the solenoid has no other purpose.

After this half-cycle of my motor, or heat engine if you
wish to regard it as such, I allow the cylinder to cool. It
recovers its ferromagnetism and the magnet sees that change and
rushes to rejoin the cylinder owing to magnetic attraction. This
means that the magnet does work in recharging the gravitational
potential shed during its early fall. It also can deliver some
more electrical output by electromagnetic induction in that
solenoid and we recover heat energy owing to the cooling of the
cylinder.

Such an engine will work because there is nothing in what
I have said that defies either experience or any law in physics.
The energy deployment involves heat energy Q input and, as
output, four energy components, the heat energy Q’ shed by
cooling, the mechanical energy developing the motor drive torque,
the electrical output on the down stroke and the electrical
output on the up stroke.

Now, obviously, logic governed by the law of conservation
of energy says that Q must be greater than Q’ by the sum of the
electrical and mechanical power outputs. Friction is part of the
heat output.

I invite you now to consider a real motor in which there is
the usual heating attributable to core magnetization losses and
heat generated by current flow in the windings. If I were to
deploy some of that heat and convert it into electrical or
mechanical power in my motor, would that defy the law of
conservation of energy? Surely, it would not, but it might
enhance the efficiency of my motor and that was a feature I found
in my tests on the motor, the subject of the patent application
which the Examiner has rejected.

Now, I am going to go further in developing these ideas for
a magnetocaloric motor. First, I will suppose that there is 100%
balance between energy input and energy output. After all, just
as we cannot get energy from nowhere, so we cannot lose energy
into that ‘nowhere’ world. So, the electrical and mechanical
power that my hypothetical motor generates draws with 100%
efficiency on the heat input, assuming I have good thermal
insulation in my motor construction. I need, therefore, to
supply heat at a temperature sufficient to exceed the Curie
temperature of that ferromagnetic substance from which the
cylinder was constructed.

If it were of iron then that would be quite a high
temperature 770 degrees C. If it were of cobalt that means 1127
degrees C. Nickel offers better prospect at 358 degrees C, but,
as this is a thought experiment, I prefer to use gadolinium which
has a Curie temperature of 16 degrees C. That is virtually
normal room temperature, so, if I am working in a cold climatic
region, I can contemplate building a normal heat pump, which need
not be very efficient, to pump heat up to a temperature above 16
degrees whilst allowing ambient cooling to provide the
temperature reduction below 16 degrees. If I were in a hot
climate then the environment could provide the heating and I
would use the heat pump in reverse as a cooling system.

Now, as every professional engineer knows, heat pumps that
change heat through a temperature range of, say, 10 degrees in
the ambient temperature range can operate with a figure of merit
as high as 10 and more. In other words, for every unit of heat
energy fed into my motor at a little above 16 degrees C, I can,
using heat shed at a somewhat lower temperature as complemented
by environmental heat, supply 10 units of excess heat (Q-Q’) to
my motor.

The fact then is that, in theory, meaning standard physics
theory and practical engineering experience, I can expect my
motor to operate to deliver up to ten times as much electrical
and mechanical power output as I supply as electrical input to
operate that heat pump. There is no breach of the law of
conservation of energy because the heat energy balance accounts
for any difference.

So, I say to the U.S. Patent Examiner responsible for my
application, that this is what I mean by magnetocaloric effects
as a factor adding efficiency to the motor I disclose in my
patent specification. It did not incorporate gadolinium, nor did
it run on that very slow heat cycle implicit in the thought
experiment described, but it did harness physical principles akin
to those described.

Whoever may read this may wonder how they can begin to check
what I say about the phenomenon of magnetocaloric effects. To
assist the reader in that question, I direct attention to a book
authored by a leading expert on the physics of magnetism. He was one of the external examiners chosen by Cambridge University to
examine my Ph.D. thesis, which was, in fact, concerned with
energy anomalies in ferromagnetic materials. The book ‘Modern
Magnetism’, by Professor L. F. Bates, was published in its fourth
edition by Cambridge University Press in 1961.

Consult that book or any other of your own choosing and try
to establish whether the heat energy supplied to a ferromagnet
to cause it to transit through the Curie temperature is the same
as the heat energy returned by cooling through the same
temperature range. Try to find any hint that the specific heat
of the ferromagnet differs in dependence upon the proximity of
that magnet in my hypothetical motor. It would have to if it is
to satisfy the requirements of the law of energy conservation,
but this is one of those questions that may still await an
answer.

Certainly, I think the physics community will adhere to the
definition of specific heat as the amount of heat needed to raise
the temperature of unit mass through a unit degree, even though
they normally measure it by what amounts to techniques involving
cooling. That shows their faith in the belief that the specific
heat is the same for tests involving increase of temperature as
it is for decrease of temperature. Note that in my hypothetical
motor I supplied heat Q to heat the ferromagnet and received in
return heat Q’ upon cooling, the difference being used to run my
motor. The latter difference can be calculated in terms of the
weight of the magnet, range of stroke, and induction effects etc
but it has to be substantial. Yet, according to the standard
theory used by physicists, as implicit in those specific heat
measurements, Q’ should equal Q.

So there is an interesting problem. Certainly it causes me
to wonder if there is another source of heat energy, perhaps the
world of entropy in our underlying environment, but, I am here
expressing the views of an engineer, though using my in-depth
knowledge of electromagnetic and ferromagnetic phenomena.

I invite anyone to contact me and enlighten me if they can
point to an error in the case I put for the hypothetical
magnetocaloric motor I describe above. I am very interested in
knowing the truths of physics which are at work in these
processes, but, please, do not quote a law of thermodynamics as
a reason for non-operability. The laws of thermodynamics are
based on past experience and I am interested in future technology
which has to be well founded and based on something new. All I
can say is that I find in my motor experiments reason to believe
that heat is being regenerated as electrical power which assists
the output of the motor.

I may add that in my Ph.D. research I confronted the problem
of why far more heat was generated by eddy currents in
transformer steel than should be the case theoretically. I did
not at the time even think that it was because the heat generated
could itself cause additional EMFs which strengthened the
circulation of those eddy currents in the transformer
laminations. Looking back at the experiments reported in my
thesis I can now see that the excess losses had to be
attributable to regeneration of electrical power from heat in a
way which tended to escalate the loss, particularly in thin large
grain electrical steel.

In the book by Bates, chapter IX between pages 327 and 371
discusses specific heat measurements in ferromagnetic materials and in
particular discusses the experimental facts concerning the
magnetocaloric effect. There is a transitional increase in
specific heat over the transition range near the Curie
temperature. There is a discrepancy between theory and
experiment which is said to be of ‘unknown origin’ (page 330).
However, there is no suggestion that specific heat values could
differ according as to whether the temperature is increased or
decreased. I qualify that by observing that it was mentioned on
page 338 that, in weak magnetic fields, the relationship between
magnetic polarization and temperature did suggest a time delay
in adjusting to the measurement conditions, of which it was said:
‘In a way, this is merely another mode of stating that hysteresis
effects are playing a small part’.

There is no breach of the energy conservation law, that is
the first law of thermodynamics, whereas the second law of
thermodynamics does not even apply because the magnetocaloric
motor is not, in a strict sense, a heat engine responding solely
to the thermodynamics of an operating fluid. The magnetic factor
can, as is well known, serve as a catalyst in redirecting the
thermodynamic energy conveyed by electrons in metals so as to
generate EMFs. This is a thermoelectric property known as the
Nernst Effect and, as with the Hall Effect, it is not governed
by the Carnot limitations which apply to the second law of
thermodynamics. In saying this I am mindful that the use of magnets as a catalyst to deflect charged ions from a heated
gaseous flow so as to generate electrical output (MHD, the
magneto-hydrodynamic technology which had its heyday in the 1960s)
does comply with the Carnot efficiency limitations. That is
because the gas molecules enter as input at a high temperature
and all leave as output through an exhaust at lower temperature.
These are the conditions demanded by the second law of
thermodynamics, but electron flow in metal according to the
Nernst Effect has no output current that is fed into an
‘exhaust’, because no current flows into the cooler heat sink.

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