Improvements in Electric Motors.
Year: 1895

page_text: Date of Application, 6th Dec., 1895
Complete Specification Left, 18th Apr., 1896-Accepted, 6th June, 1896
Improvements in Electric Motors.
1, FELIPE ZAPATA, of 31 Homefield Road, Chiswick, London, in the County
of Middlesex, Shipping Merchant, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in the means of utilizing the mechanical
power produced by electric energy in electric motors.
The turning motion of the driving shaft of electromotors, as commonly made,
is produced by the rotation of one of the essential organs or elements of the machine,
generally the armature, which is firmly fixed upon the said shaft. The other
element, the field magnet,-is stationary and forms part of the frame.
The essential features or characteristics of this invention are the following
ones:-
1st. Neither of the two elements of the electromotor is stationary. The field
magnets and the armature, or the two armatures in case the machine should have
no field magnets, are constructed in such a manner that they may be placed
in the usual position to give the best effect, having their centres on the same
axis so as to revolve freely in opposite directions when excited by the electric
current.
2nd. The field magnets and the armature have central journal-boxes to run loose
upon a stationary shaft; or the shaft may be made to revolve upon suitable
bearings, and in this case one of the elements, either the field magnets or the
armature, is fastened to the revolving shaft, the other element having a central
journal box to run loose upon the same shaft.
3rd. Each of the elements of the motor, i.e. the field magnets and the armature
carries a pulley, cog wheel or any other suitable mechanical appliance to transmit,
separately, its own motion either to the machinery or carriage to be moved, or to a
separate shaft to be used as a driving shaft.
4th. The direction of motion of one of the elements, either the field magnets or
the armature, is reversed by means of suitable gearing in such a manner that both
elements act jointly in imparting motion in the same direction either to the
machinery or carriage to be moved or to a separate driving shaft.
In short, the nature of this invention consists in making movable the two essential
elements of the motor, viz. the armature and the field magnets, and in mounting
them in such a position that the electric energy causes them to revolve upon the
same axis in opposite directions, the two revolving elements being connected by
suitable gearing, which reverses the direction of motion of one of them, with a
separate driving shaft or directly with the machinery or carriage to be moved, in
such a manner that both elements act jointly to produce mechanical effort in the
same direction.
Dated this Fifth dox of December 1895

page_text: I, FELIPE ZAPATA, 31 Homefield Road, Chiswick, London, Shipping Merchant,
do 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:-
This invention relates to improvements in the means of utilizing the mechanical
power produced by electric energy in electric motors.
The turning motion of the driving shaft of electro-motors, as they are commonly
made, is produced by the rotation of one of the essential organs or elements of
the machine, generally the armature,-which is firmly fixed upon the said
shaft. The other element, the field-magnets, is stationary and forms part of the
frame.
The essential features or characteristics of this invention are the following
ones :
1st. Neither of the two elements of the electro-motor is stationary. The field-
magnets and the armature, or the two armatures, in case the machine should
have no field-magnets, are constructed in such a manner that they may be placed
in the usual position to give the best effect, having their centres on the same
axis so as to revolve freely in opposite directions when excited by the electric
current.
2nd. The field-magnets and the armature have central journal boxes or
axle-boxes to run loose upon a stationary shaft; or the shaft may be made to
revolve upon suitable bearings, and in this case one of the elements, either the
field-magnets or the armature, is fastened to the revolving shaft, the other.
element having a central journal-box or axle-box to run loose upon the same
shaft.
3rd. Each of the elements of the motor, i.e. the field-magnets and the armature
carries a pulley or cog-wheel, or any other suitable mechanical appliance to transmit
separately its own motion either to the machinery or carriage to be moved, or to a
separate shaft to be used as a driving shaft.
4th. The direction of the motion of one of the elements, either the field-magnets
or the armature, is reversed by means of suitable gearing, in such a manner that
both elements act jointly in imparting motion in the same direction, either to the
machinery or carriage to be moved, or to a separate driving shaft.
In short, the nature of this invention consists in making movable the two essential
organs or elements of the motor, i.e. armature and field-magnets, and in mounting
them upon the same shaft in such a position that the electric energy causes them to
revolve in opposite directions, the two revolving elements being connected by
suitable gearing, which reverses the direction of motion of one of them, either
with a separate driving shaft, or directly with the machinery or carriage to be
moved, in such a manner that both elements act jointly in producing mechanical
effort in the same direction.
Before describing the details for carrying into practice this invention, I will
show the principles upon which it is based. Referring to Fig. 2 of the annexed
drawings, letter M is supposed to represent a continuous current motor, constructed
for experimental purposes. The field-magnets may revolve upon the armature
shaft, or they may be kept stationary whilst the armature revolves. It is supposed
that the field-magnets are excited by a separate current in order to keep a
constant number of effective magnetic lines equal to 10,000,000. The number of
conductors around the armature is 100. The sum of the resistances of the
circuit formed by the motor and the generator which supplies the electric current
is equal to 1 ohm.

page_text: I have taken the above numbers solely for the purpose of permitting the
calculations to be verified at a glance. For this same reason I will not take into
consideration unavoidable losses of energy by friction, demagnetization, eddy
currents, magnetic leakage and the like.
If we turn on an electric current into this motor, the field-magnets being stationary,
we observe that the current flows from the brush B into the commutator-bar
in contact with it, and thence divides into two parts in the two circuits of the
armature to join again at the commutator bar in contact with the brush B'. The
coils of the two circuits being of the same sort of winding, two consequent
poles N S¹ are produced in the iron core of the armature, and a reaction is set up
between this and the field-magnets. The mutual attraction of the poles N S'
and S N and the mutual repulsion of the poles N N¹ and SS' causes the arinature
to turn in the direction of the arrow. 'The commutator bars will come up succes-
sively into contact with the brushes B B', which being attached to the stationary
field-magnets keep immovable the position of the line of commutation n n³,
so that although the poles N¹ S₁ are always receding in the armature, they are
always at the same distance of the field-magnets poles, thus producing a continuous
motion.
If we examine the same motor when the field-magnets are allowed to revolve
freely upon the armature shaft, we observe that when the reaction is set up, the
field-magnets are driven in a direction opposite to the motion of the armature.
As the brushes B B₁ are attached to the field-magnets, they turn with them at the
same time that the commutator is carried around by the armature in opposite
direction. The neutral line of commutation n n' follows the motion of the field-
magnets, and the poles N' S¹, although receding faster than formerly in the
armature, are always at the same distance of the field-magnets poles, so that a
continuous motion is also produced.
The actions and reactions in the armature are in this case the same as when one
of the organs of the motor was stationary. In order to ascertain whether the
power of the motor has suffered any alteration under the new conditions of working,
it is necessary to compare the results in both cases: i.e. when the armature is
running and the field-magnets are stationary, and when both organs rotate in
opposite directions. Fig. 1 shows the results of working the motor under different
currents according to the following equations: The counter-electromotive force E
generated in the armature is:
En CN108: number of volts, where n expresses the number of turns of
the armature per second, C the number of conductors of same counted all around
the external periphery, and N the whole number of the effective magnetic lines
in the field-magnets.
The current, i in the armature is :

page_text: It is supposed that the current of supply is equal to 80 amperes at a pressure of
80 volts. As expressed above:
N
1
10,0000,00
C = 100
R = 1 ohm.
To calculate the results when the field-maguets and the armature are revolving
upon the same shaft in opposite directions, it must be considered :
1st. That the angular force of action is equal to the angular force of reaction.
If the armature is driven by a force of 100 pounds acting with a leverage of
foot, the field-magnets are driven, in opposite directiou, by an equal force with
an equal leverage. Therefore, if the motion of one of the revolving bodies is
reversed and the two angular forces, whatever their magnitude may be, act in
parallel lines against the same resistance, a composition of parallel forces will take
place which doubles the power and halves the resistance. By consequence: the
power of the motor working under the new conditions is equal to the power of the
armature multiplied by 2.
2nd. The armature turns twice in the magnetic field at every single revolution
upon its shaft. By doubling the relative speed, the counter-electromotive force is
increased and the mechanical force propelling the armature is diminished; but the
resistance to motion is again halved, because the mechanical effect of doubling the
number of revolutions of the armature in the magnetic field, per each turn of
the shaft, is equivalent to doubling the leverage of the force acting upon the
shaft.
Let it be supposed that the motor is to be run according to the law of maximum
activity; i.e. when

page_text: being equal to 80 volts, E must be equal to 40: To generate a current of
40 volts
N being 10,000,000,
C being
=
100,
the armature must turn 4 times per second in the magnetic field.
R being = 1 ohm the current will be 40 amperes.
In order that the armature may revolve in the magnetic field 4 times per second,.
to keep a current of 40 amperes, the real speed of both organs upon their commo
shaft must be reduced to 2 turns per second. To reduce the speed of both organs to
2 turns per second the driving pulley must be loaded with a resistance 4 times
greater than the load which the motor carried, under the same current, when the
field-magnets were stationary, because by the composition of forces, the total load
is halved, and by doubling the number of the armature turns in the magnetic field,.
per each turn of the driving shaft, the remaining resistance is halved again.
What has just been explained can be more clearly seen in Fig. 1. The arc 4 4'
represents the number of revolutions per second of the armature in the magnetic
field when working at the rate of maximum activity.
If we take 4 revolutions, the counter-electromotive force
2π Τ
-
295 foot pounds per turn
2 T x 4 1180 foot pounds per second.
If we suppose that all the angular force of action is concentrated at the point 4,.
extremity of the lever a 4, which represents the armature, and all the force of
reaction is equally concentrated at point 4', which is stationary, the point 4 will
move in the direction of the arc towards point 4. The mechanical power of
lever a 4 during the second of time which it takes to go over arc 4 4' (represented
by the square 404 411 41), is equal to 1,180 foot-pounds. If the distance covered
by the resistance z z¹ during the same time is four feet, the work done by the
1,180
motor during one second is equal to pound feet 295 pounds raised to a
4
height of four feet. This would be all the work or mechanical output of the motor
for each second of time, with a current of 40 amperes, in the case that the armature
were to revolve within a stationary magnetic field.
Let us now consider the case in which the two levers a 4 and a 4¹ move.
simultaneously in opposite directions. The number of revolutions of the armature
in the magnetic-field being the same as before, the electric energy in volt-amperes,.
or its equivalent in pound feet, will always be represented by the square 40, 4
44; but the speed of the driving shaft will be reduced to 2 turns per second.
Lever a 4, or the armature, will cover as in the preceding case, the arc 4 4¹ in
the same space of time and its mechanical power will be equal to 1180 foot-pounds;
but as the driving shaft has turned twice only, the distance covered by the
resistance is two feet, represented by arc xx¹. The work done by the armature
1,180
foot pounds 590 pounds raised to a height of two feet
2
is, therefore, equal to

page_text: in a second. The work done by the armature is in both cases the same,
because 295 x 4 = 590 × 2.
In the second case what has been lost in velocity has been gained in force.
But the force of attraction concentrated in the point 4, extremity of lever a 4,
could not do any work without an equal and contrary reaction at point 4. If the
levers a 4 and a 41 work together both are driven towards each other with an equal
force. The mechanical power of the lever a 4 to cover the arc 44' being 1,180 foot-
pounds, it is evident that the mechanical power of lever a 4' to cover the same
arc, at the same time in opposite direction is also equal to 1,180 foot-pounds. As
the direction of motion of one of the levers is reversed and both work parallely
against the same resistance, their combined force is equal to the action and reaction
put together, namely
11801180 foot-pounds
=
1180 lbs. raised to a height of 2 feet.
To prove that this result is consistent with the theory of reversibility, let us
consider a circuit, Fig. 2, composed of a dynamo D and a motor M, exactly alike,
both with movable organs. If mechanical power is applied to the armature of D
for causing it to revolve, we find that as soon as the organ begins to rotate within
the field-magnets, there arises between the two organs a reaction to stop the motion.
As the field-magnets can revolve freely, they yield to the reaction and it is impossible
to generate electricity, the same as it is impossible to tighten a rope by pulling at one
end of it whilst the other end is loose. Mechanical power applied to the armature
cannot, therefore, be converted into electric energy except with the concurrence
of another force of equal magnitude to counteract the reaction which tends to stop
the motion. The concurrent force may consist, either in mechanical power applied
to the field-magnets, to drive them in opposite direction to that of the armature, or
in a resistance to prevent the field-magnets from giving way. If the armature and
the field-magnets are driven towards each other by mechanical force the horse-
power spent to generate a certain current will be double than that which is spent
when the field-magnets are kept immovable by means of a resistance. If this
resistance consists in a weight attached to the rim of the field-magnets to counter-
balance the force of reaction, or if the resistance is arranged as shown in Fig. 2,
where the counteracting force is measured by a dynamometer fixed upon the ground,
it will be observed that the amount of energy spent in lifting the weight or in
deflecting the dynamometer is equal to the horse-power applied to the armature.
The amount of energy required at the dynamo to generate a current is, therefore,
equal to the action of the mechanical force plus the counter-force which overcomes
the reaction to stop the motion.
According to the theory of reversibility the dynamo converts mechanical power
into electric energy, and the motor reconverts the electric energy into mechanical
power. The two dynamometers shown at Fig. 2, suggest that an important term
had been omitted on each side of the equation. We may see there that the energy
spent in the dynamo to counteract the reaction of the field-magnets reappears in the
motor in the form of motion.
The principles upon which this invention is based may be summarized as
follows:
1st. The numerical value of factor n in the equations
E = n C N 108 and
i 2n Tx 1,356 depends only upon the number
of times that the conductors around the armature cross the magnetic field. Conse-
quently if the armature and the field-magnets revolve at the same time, with equal
velocity, in opposite directions, each revolution of the armature, with relation to
space, must be counted as two turns in the magnetic field.
2nd. Power being the expression of two factors, force and speed, if the speed is
halved the force is doubled and vice versa.

page_text: 3rd. Reaction being equal to action, the turning moment of the armature is
equal to that of the field-magnets; and
4th. The resultant of two parallel forces acting conjointly is equal to their sum.
This invention does not interfere with the condition of the motor as an
electrical machine. Its object being to utilize the reaction of the organ which
in all electric motors is kept stationary, it matters not whether the machine is a
direct current motor or an alternate current one, either with a stationary or a
travelling magnetic field. This invention is applicable to all sorts of machines in
which energy in the form of electric-currents is converted into energy in the form
of mechanical power. To limit its use to a particular sort of electro-motors
would be as opposed to common sense as to limit the use of the blast-pipe, for
instance, to a particular type of locomotive. Therefore, I do not confine myself to
any particular kind or type of machine.
I will now show the manner in which any person skilled in the art to which
this invention appertains, may apply it to the different types of electric motors
actually in use.
There is a great variety of shapes in electric motors, but for all purposes relating
to this invention, the different forms may be classified as follows:
1st. Motors in which the outside organ, generally a ring or a polygonal figure, is
perfectly symmetrical all around.
2nd. Motors in which the two organs, which are symmetrical all around, stand
side by side facing each other, or in which the armature is placed between two
multipolar field-magnets shaped like a crown-wheel or a lantern-wheel, the two
multipolar field-magnets being connected to each other by means of bars, or by
consequent poles.
3rd. Motors with field-magnets shaped in the form of a rectangle, or a lozenge,
or an ellipse. These forms of field-magnets have always consequent poles.
4th. Motors in which the field-magnets are horse-shoe shaped, or have two
straight limbs connected by a yoke on one side and two pole pieces on the other
side.
The accompanying sheets of drawings illustrate the manner of applying this
invention to the four classes of motors above referred to. In order to make the
drawings as clear as possible, contact brushes and electrical conductors have been
omitted. The electrical arrangements are exactly the same as are usual in motors
with a stationary organ. To supply the current to the moving armature and field-
magnets, slip-rings in contact with fixed brushes, or grooved rings in contact with
metalic flexible cords are used. The slip-rings or grooved rings, which are well
known appliances, are properly insulated and fixed upon one of the bosses or hubs
of the outside organ, as shown at R R in Figures 3, 6, 7, 8 and 9. The contact
brushes to supply the current are fixed in a suitable manner upon the frame of the
motor according to the judgement of the designer or maker. As the brush-holder,
in direct current-motors, must keep always the same position respecting the field-
magnets poles, it must be attached to one of the bosses or hubs of the field-magnets,
as shown in Figures 3, 6, 7; and 8. In case the field-magnets are secured upon the
shaft, as in Figure 13, the slip-rings R R and the brush-holder B B' must be also
secured to the shaft for the purpose of keeping immovable the position of the
brushes respecting the field-magnets poles. The inside organ may be supplied
with electric currents, either by passing the conductors through a central hole in
the shaft, as shown at e Fig. 13, or by means of brushes and slip rings placed in a
manner similar to B. B' R R in Figure 9. When a current is to be carried from
one of the moving organs to the other, brushes must be attached to the former and
slip-rings or a commutator to the latter, as the case may be. It is clear that all
connecting wires must be properly secured to prevent their being thrown out of
position by the centrifugal force when the motor is running.
The outside organ of all motors of class number 1, which include most of
alternate-current motors, is adapted to rotate by fixing each side of the rim to a
spider with a central boss or hub suitable to fit the axle-box, as shown by

page_text: letter S in Figures 4, 11 and 13. Disks or spherical concave segments, with
central hubs, and perforations all around for ventilation, bolted to flanges built
upon each side of the rim, will in some cases be preferable to spiders; but I
do not bind myself to any particular means to support the outside organ upon
its shaft.
The inside organ of all motors is secured upon the shaft in the usual manner.
Fig. 3 shows the manner of mounting upon their shaft the two organs of a
direct-current motor of the first class. L is the frame; E is the shaft running
upon the usual bearings; F the field-magnets, which are ring shaped, with two
consequent poles. The field-magnets are supported and kept in position by the
arms S S¹ fixed upon the bosses or hubs K K which carry the central axle-boxes.
Upon the boss K on the left hand side are fixed the slip-rings R R in contact with
brushes, not shown in the drawing, by means of which the electric current is
supplied to the motor. Upon the same boss are set the brush-holders B B' to
supply the current to the commutator C attached to the armature A, which is
firmly secured upon the shaft E in the usual manner. On the right hand side the
boss K carries the driving pulley p attached to the outside organ. The other
driving pulley p', corresponding to the armature, is fixed upon the shaft E. The
opposite motion of the two driving pulleys p p is transmitted by belts to the
machinery to be moved or to a separate drum or pulley. In order to reverse
the motion of one of the driving pulleys, one of the belts is crossed and the other
is open, as shown in Fig. 2.
The manner in which the motor works is quite simple. The field-magnets F
turn one way carrying with them the brush-holder and the pulley p, and the
armature A turns the other way carrying with it the commutator C and
the pulley p. The direction of motion of one of the pulleys being reversed by the
crossing of one belt, the driving force of the motor is transmitted in one direction.
Fig. 3 shows only one pair of slip-rings; but additional rings must be fixed upon
the boss K if the motor is to be supplied with currents from different sources.
Fig. 5 is a polygonal form of field-magnets with inward poles. The holes on the
rim show the places to fix the ends of the spider spokes. Instead of fixing the
spokes upon the rim itself they may be bolted to projections t.
Figures 8 and 9 show the manner of mounting the two organs of motors of the
second class. Fig. 8 is a direct-current motor with crown-wheel shaped armature
and field-magnets facing each other. The two organs run loose upon a stationary
shaft E, and each carries a driving pulley p p attached to the spiders bosses K K.
Fig. 9 is an alternate-current motor. The armature A is secured to the shaft E
and the two crown-wheel shaped field-magnets F F firmly connected to each other
by the bars rr, carry on one side the slip-rings R R R R and on the other side
the driving pulley pl.
Field-magnets shaped like a lantern-wheel are mounted in a manner similar to
Fig. 9.
Fig. 13 is a section of the working part of a direct current motor with an outside
armature A. The field-magnets F are fixed to the shaft. The current to excite
them is carried through a hole e made in the shaft E. The slip-rings R R R R
and the brush holders B B are in this case attached to the shaft E. The
pulleys p p are attached, one to the boss K and the other to the shaft E.
Fig. 6 show the manner of mounting horse-shoe shaped field-magnets. The
shaft is passed through the yoke of the electro-magnet, which has projecting
bosses on each side to carry the slip-rings R R and the brush-holder B B. The
two pole pieces are supported by arms S fixed upon a boss K to which is attached
the driving pulley p. The other pulley attached to the shaft E is not shown in
the drawing.
Motors of the third class are mounted as shown in Fig. 7. The shaft is passed
through the yokes of the opposite field-magnets in the same manner described
respecting Figure 6. The pulley attached to the shaft E has been omitted.
Fig. 10 contains a front view and a section of the axle-box fitted in the central

page_text: boss or bub of the movable organs of the motor in combination with a stationary
shaft. yy are brasses fitted in a conical hole in the hub K; W are feathers to
keep the brasses in position; v vrv screws to hold the brasses; h¹ washer,
collars secured to the shaft to prevent the running organ from shifting end ways;
holes made in the shaft, which is tubular, to supply oil to the sliding parts.
The hand-wheel is meant to change now and then the position of the shaft so that
the wear and tear be equal.
Fig. 12 contains front view and section of an antifriction roller-box, which is
fitted in each of the central hubs of one of the rotating organs when the other is
secured upon the revolving shaft. The arrows marked on the front view of the
left hand side of the section, show that the rollers ff serve the purpose of trans-
mitting the motion of each of the revolving organs to the other one. The
diameters of the rollers, that of the shaft E, and that of the hole in the hub K
being in the proportion of 1: 2: 4 they keep immovable when the motor is
running. In practice it is convenient to alter slightly the above proportions, so
that the roller-box may have a slow motion around the shaft and the rollers may
wear equally. The roller-box is built in the form of a lantern-wheel, its two end
rings being connected to each other by means of metal pieces el el el. The
rollers ffare kept in position as shown at gg, and they are prevented from shifting
endways by the circular plates m m¹ fitted to the hub K and secured by bolts i i.
A thick washer, not shown in the drawing, with cavities to fit the nuts of the bolts,
keeps them out of the way. The oil to lubricate the sliding pieces m m' is put into
the box through a hole which is closed by a screw plug.
Fig. 11 shows a manner of reversing the motion of one of the revolving organs
of the motor by means of cog-wheels. S is the spider supporting the exterior
organa cog wheel attached to the boss K; another wheel mounted upon a
separate driving shaft, which carries the wheel in gear with an intermediate
wheel driven by the cog-wheel upor. shaft E. The diameters of wheels [11
7111 are in this proportion : : : Diameter of wheel j is equal to the
radiuses of + 1 + 1.
I do not claim any invention relating to gearing, and I do not bind myself to any
special system to reverse the motion of one of the revolving organs of the motor,
because for one purpose a particular gearing may be suitable and not for another.
It is obvious that the power of the two revolving organs may be transmitted
without reversing the direction of motion of one of them and in such a case each
organ will act separately from the other. I do not bind myself to reverse the
direction of motion of any one of the organs in all cases; although I am aware that
the motor is more efficient when the joint power of the two organs is applied in one
direction against the same resistance.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:
In an electric motor, namely, in a machine in which energy in the form of
electric-currents is converted into energy in the form of mechanical power, the
construction and fitting of the machine in such a manner that the two essential
organs or elements of the motor, (field-magnets and armature), are movable and
fitted to rotate upon the same shaft, in opposite directions, when excited by electric
energy, each of the two revolving elements being connected, by suitable gearing,
either with a separate driving shaft or directly with the machinery or carriage to
be moved, so that both elements or organs act jointly in imparting motion to said
shaft, machinery or carriage, all substantially as herein before described.
Dated this 18th day of April 1896.
FELIPE ZAPATA.