Improvements connected with Assistant or Auxiliary Electro Motors.
Year: 1893

page_text: Complete Specification Left, 23rd Aug., 1895-Accepted, 23ra oʻpl., 1895
COMPLETE SPECIFICATION.
Improvements connected with Assistant or Auxiliary Electro
Motors.
LA SOCIÉTÉ ANONYME POUR LA TRANSMISSION DE LA FORCE PAR
L'ELECTRICITÉ of 16, Rue Drouot, Paris in the Republic of France does hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
Assistant or auxiliary motors are at present very frequently employed for
various purposes, steam or water under pressure being employed in various forms.
Electrical energy has also been employed for the same purposes, but hitherto this
class of motor has been very little developed.
Now the object of the present invention is a very general but accurate solution
of providing such a motor and one which is capable of manifold applications.
If a differential movement in its general arrangement be considered as two bevel
wheels gearing in an inverse direction with a series of movable pinions, then we
know that, if we impart to the two wheels an equal speed in opposite directions, the
pinions remain stationary; but when the speed becomes unequal, the pinions will
travel round a common axis at a speed equal to half the difference in the speed of
the wheels.
Referring to the accompanying sheet of drawings, if we call A and B, Figure 1, the
two wheels, and CC the pinions which are supposed to operate a spur wheel, the two
wheels A and B will be driven by two dynamos G and G', R R¹are their magnetic
fields and r a resistance; the two rings are fed from a common source of electricity
having constant potential: when the fields are equal, the speed of the two rings will
be the same; if the fields, however, become different, the speed will vary, and the
differential gearing shown in CC will come into action. It will be sufficient,
therefore, in order to produce a movement, to create a difference between these
fields. By suitably regulating their respective potentials, the speed of the
differential gearing may be given the desired extent and direction.
In carrying out our invention, we prefer to employ the arrangement of differential
gearing shown in section and elevation of Figure 2, in which the wheels A and B
engage with four small cog wheels revolving on the spokes of a spur wheel D; the
latter then forms the driving part capable of producing such movements as it may
be desired to obtain.
The two wheels A and B being connected with the leads of two dynamo
machines G and G¹, as we have already stated and as is shown in Figure 1, the
fields will be arranged in the manner shown in Figure 1; a commutator provided
with a handle m will act on the resistance r; when this handle is operated, the
values of the two fields R and R' will vary in an inverse direction, starting from
the symmetrical position a b, and the differential gearing will move in one direction;
if, instead of moving the handle to the right, it be moved to the left, the direction
of the movement of the gearing will be reversed.
The dimensions of the machines may be calculated so that, for each variation, there

page_text: will result given differences of speed between the two machines G and G' and
consequently in the differential gearing.
The application of this principle to driving a machine at a distance may be
effected in the following manner :-
The following conditions must be observed, namely, the apparatus which is to be
driven must be connected in such a way that it assumes precisely the position it is
intended to have; it must be arranged so that, if any accidental cause happens to
shift it, it recovers of itself; it is also almost always indispensable that the stoppages
are made in a progressive manner, because of the size of the masses which may be
set in motion.
Figure 3 shows the arrangement adopted by us.
The differential gearing is shown at A B C D, G and G₁ are the two rings,
R and R are their magnetic fields, r is a resistance, a second resistance inserted
in the circuit of the fields and situated at the operating point; the gearing D of
the differential train operates, on the other hand, an apparatus for moving the
commutator m which acts on the resistance r.
Supposing that the handles m and m¹ be placed in such a position as regards one
another that the potential in the two fields is equal; the two dynamos will revolve
at the same speed and the gearing D will remain immovable; if m' be then turned
so as to increase the resistance of 1, one of the fields will become weaker and the
other will not change, the gearing D will commence to revolve and the transmission
will be made in such a way that m will be attracted in such a direction that the
portion of the resistance which is inserted in the circuit diminishes, it is evident
that D will revolve attracting m until the equilibrium is re-established between
the two fields, at this moment the apparatus driven by D will have assumed a
fresh position of equilibrium which will be caused by the resistance inserted by
means of m¹.
It is evident that if, in consequence of some accidental cause, the guiding
apparatus were drawn out of its position of equilibrium, it would attract m and
destroy the equilibrium of the fields, which would return it automatically to its
position of equilibrium.
When a movement is made, the difference of equilibrium between the fields
diminishes in proportion as the apparatus advances towards its position of
equilibrium, the speed of the gearing D also diminishes, the return to a stationary
position of equilibrium is thus made gradually. It will be seen that the
manoeuvering is done entirely on the magnetic fields, that is to say, on a weak
potential, which is of importance, as regards the cost and duration of the operating
commutators. It is not necessary to cause the rings to revolve the whole time, the
current may be cut off after each operation, and, in this case, it is always cut off at
a very weak potential.
Instead of carrying out the operation hereinbefore described on the fields, it may
also be done by varying the difference of potential at the terminals of one of the
rings, by inserting a resistance which would be automatically removed by the same
process.
We will now describe the main applications of the induction hereinbefore
described.
1ST. ITS APPLICATION FOR OPERATING RUDDERS.
This application connects directly with what has been described herein before;
the spur wheel D operates the rudder resistances corresponding to a certain angle
made by the rudder, which resistances are operated by two commutators m and m'
which are regulated in such a way that, when m¹ is placed on a given key, m places
itself on a corresponding key.

page_text: guiding on the magnetic fields, or that in which the regulation of the electro-
motive force is done at the terminals of the rings. This latter arrangement may be
deemed preferable. In fact, the source which produces the fields may be situated
on the torpedo itself. In that case, it will be sufficient to have three cables
bringing the current, 1st. to the motive apparatus of the torpedo; 2nd. to the
mechanism for operating the rudder or rudders; these three conductors being
capable of being enclosed in one case.
We need not enumerate various other applications, such as electrometers, are
regulators, electric traction, etcetera.
We would further remark that the arrangements hereinbefore described are not
limited to such, and we reserve the right of employing others whilst preserving the
essential principle of our invention.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. A system of assistant or auxiliary electro-motors characterised by the com-
bination of a differential train or gearing, the two wheels of which are operated by
two dynamo electric machines, the movements of this differential gearing being
determined by the difference in the speed of these two machines resulting from
differences caused in their magnetic fields.
2. The general arrangement described for causing these differences and causing
the parts operated to assume a given position.
3. The particular arrangements described for applying this system to various
particular cases hereinbefore described: the whole substantially as hereinbefore
described and shown as an example on the accompanying drawing.
Dated this 22nd day of August 1002
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.