Improvements in Electro-dynamic Motors, and in Methods of and Apparatus for Regulating the вате when Used Stationary or on Electric Railways.
Year: 1885

page_text: Improvements in Electro-dynamic Motors, and in Methods of
and Apparatus for Regulating the вате when Used
Stationary or on Electric Railways.
I THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent do hereby declare the nature of this invention for
"IMPROVEMENTS IN ELECTRO-DYNAMIC MOTORS AND IN METHODS OF AND
APPARATUS FOR REGULATING THE SAME WHEN USED STATIONARY OR ON ELECTRIC
RAILWAYS" a communication to me from abroad by Frank Julian Sprague of New
York, in the County and State of New York, United States of America, Electrical
Engineer, to be as follows:-
A portion of the invention relates to a method of operation or regulation of &
shunt wound electro-dynamic motor or a circuit of constant difference of potential,
which may be a circuit of a system of electric lighting or an electric railway
system.
This method consists in first introducing the motor into circuit with a very
strong field and with a small difference of potential at the terminals of the armature
circuit so that the motor starts slowly; then progressively raising the armature
circuit potential until that circuit is brought up to full potential, and then, to still
further increase the speed, weakening the field magnet strength; after this during
the operation of the motor, its speed and power are diminished or increased by
strengthening or weakening the field magnet.
To carry out this method it is necessary to construct or provide the motor with
means whereby the strength of the field magnet and the current in the armature
may be regulated independently of each other so that the changes of one will not
affect the other. To do this an adjustable resistance may be placed in the field
circuit and another in the armature circuit; or the adjustable resistance inay be
placed in the armature circuit and any other known way employed of varying the
magnetizing effect of the field coils.
My said foreign correspondent has, however, devised an apparatus in which the
independent regulation of the field and armature is performed by the movement of

page_text: a single switch which apparatus forms another part of the invention. This
apparatus consists of a series of resistance coils in the field circuit of the motor and
contact terminals for said resistance coils, a series of resistance coils in the armature
circuit and contact terminals therefor, a long contact block in the armature circuit
contiguous to said field resistance contacts, a similar long contact in the field circuit
contiguous to said armature resistance contacts, and a movable terminal connected
with the supplying circuit travelling between said field resistance contacts and the
contiguous armature circuit contact and between said armature resistance contacts
and the contiguous field circuit contact. When the moving contact travels between
the armature resistance contacts and the long field circuit contact, resistance is cut
in and out of the armature circuit while the field circuit is not affected; and the
continuation of the movement brings the contact between the field resistance
contacts and the long armature circuit contact which changes the field circuit
without affecting the armature current.
In an electric railway, if a single motor is used to propel a car, the above applies
as well as to a stationary motor, and similar apparatus is employed in both cases.
But when two or more motors are placed upon the same car or carriage or train
of cars or carriages to propel it, it is desirable to regulate all these motors simul-
taneously and to have the regulating apparatus for all of them situated on one car
or carriage or at one point so that one man can control all the motors on the car
carriage or train.
To this end, a common field circuit is provided for all the motors and a common
armature circuit also, all the field magnets being in shunt relation to all the
armatures, and each of these circuits is provided with an adjustable. resistance
whereby the field magnets and armatures are regulated independently. In addition,
a current reverser may be placed in the common field circuit or the common
armature circuit or one may be placed in each of these circuits. Thus the move-
ment of all the motors may be reversed. The circuit reverser or reversers may of
course also be employed with a single stationary or locomotive motor.
The field magnets of the motors may be in series or in multiple arc or multiple
series in their common circuit; and the armatures also may be connected in any
one of these different ways.
When two or more stationary motors are used together they may be arranged
and operated in the same way as the locomotive motors just described.
There is, however, an additional advantage of the independent regulation of field
and armature in railway motors. My foreign correspondent desires to employ in
railways a method of braking a train which consists in raising the counter electro-
motive force of the motor or motors propelling the train until it exceeds the initial
electro-motive force in the line. This is done by increasing the strength of the
field magnet or magnets and it is therefore necessary that these should be regulated
without affecting the armature current.
The Invention has been described with particular reference to simple shunt-
wound motors but the same methods of and apparatus for regulation are applicable
to any motor in which the main field is in shunt relation to the armature whether
or not there be a coil cumulative or differential in series with the armature. The
term "shunt-wound" is intended to cover any form of machine in which the main
field is in shunt relation to the armature,
t

page_text: and Apparatus for Regulating the same when Used
Stationary or on Electric Railways.
I THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex, Patent Agent 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 :-
A portion of the invention relates to a method of operation or regulation of a
shunt-wound electro-dynamic motor on a circuit of constant difference of potential,
which may be a circuit of a system of electric lighting or an electric railway
system.
This method consists in first introducing the motor into circuit with a very
strong field and with a small difference of potential at the terminals of the
armature circuit so that the motor starts slowly; then progressively raising
the armature circuit potential until that circuit is brought up to full potential,
and then, to still further increase the speed, weakening the field magnet strength;
after this, during the operation of the motor, its speed and power are diminished
or increased by strengthening or weakening the field magnet.
In order to carry out this method, it is necessary to construct or provide the
motor with means whereby the strength of the field magnet and the current in
the armature may be regulated independently of each other so that the changes
of one will not affect the other. To do this, an adjustable resistance may be
placed in the field circuit and another in the armature circuit; or, the adjustable
resistance may be placed in the armature circuit and any other known way
employed of varying the magnetizing effect of the field coils.
This
My said foreign correspondent has, however, devised an apparatus in which the
independent regulation of the field and armature is performed by the movement of
a single switch which apparatus forms another part of the invention.
apparatus consists of a series of resistance coils in the field circuit of the motor,
and contact terminals for the said resistance coils, a series of resistance coils in the
armature circuit and contact terminals therefor, a long contact block in the armature
circuit contiguous to the said field resistance contacts, a similar long contact in the field
circuit contiguous to the said armature resistance contacts, and a movable terminal
connected with the supplying circuit, travelling between the said field resistance
contacts and the contiguous armature circuit contact, and between the said armature
resistance contacts and the contiguous field circuit contact.' When the moving
contact travels between the armature resistance contacts and the long field circuit
contact, resistance is cut in and out of the armature circuit while the field circuit
is not affected; and the continuation of the movement brings the contact between
the field resistance contacts and the long armature circuit contact, which changes
the field circuit without affecting the armature current.
In an electric railway, if a single motor is used to propel a car,
the above,
applies as well as to a stationary motor, and similar apparatus is employed in
both s

page_text: But, when two or more motors are placed upon the same car or carriage or train
of cars or carriages to propel it, it is desirable to regulate all these motors simul-
taneously, and to have the regulating apparatus for all of them situated on one
car or carriage or at one point so that one man can control all the motors on the
car, carriage or train.
To this end, a common field circuit is provided for all the motors, and a common
armature circuit also, all the field magnets being in shunt relation to all the
armatures, and each of these circuits is provided with an adjustable resistance
whereby the field magnets and armatures are regulated independently. In addition,
a current reverser may be placed in the common field circuit, or in the common
armature circuit, or one may be placed in each of these circuits. Thus, the
movement of all the motors may be reversed. The circuit reverser or reversers
may of course also be employed with a single stationary or locomotive motor.
The field magnets of the motors may be in series, or in multiple are or multiple
series in their common circuit; and the armatures also may be connected in any
one of these different ways.
When two or more stationary motors are used together they may be arranged
and operated in the same way as the locomotive motors just described.
There is, however, an additional advantage of the independent regulation of field
and armature in railway motors. My foreign correspondent desires to employ in
railways, a method of braking a train, which consists in raising the counter electro-
imotive force of the motor or motors propelling the train until it exceeds the initial
electro-motive force in the line. This is done by increasing the strength of the
field magnet or magnets, and it is therefore necessary that these should be regulated
without affecting the armature current.
And in order that the said Invention may be perfectly understood, I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several figures on the accompanying sheet of drawings, the same letters of
reference indicating corresponding parts in all the corresponding figures.
Figures 1 and 2 relate to the general idea of regulating the field magnet and
armature independently.
Figure 1 is a diagram of a motor provided with regulating devices embodying
this feature of the invention, and
Figure 2 a similar diagram showing a different field magnet regulator.
1, 2 are main conductors of a supplying circuit, preferably a circuit of constant
difference of potential, with which it is preferred to use this invention. 3, 4 is the
armature circuit and 5, 6 the field circuit of a shunt wound electro-dynamic
motor E. In the field circuit 5, 6 is an adjustable resistance e (figure 1) and in
the armature circuit 3, 4 is an adjustable resistance f.
It will be seen, that each of these resistances is controllable independently of
the other. Thus, to increase the strength of the field magnet, a portion of the
resistance e is cut out of circuit and to decrease its strength more of the resistance e
is placed in circuit. Thus, the regulation of the field magnet is performed without
affecting the armature circuit.
The current in the armature is similarly controlled without affecting the field
magnet by the adjustment of the resistance f.
The regulating means for the two circuits may include also a circuit reverser for
each circuit, d or g; whereby the current in either circuit is reversed without
affecting the other circuit.
L
The field magnet regulator shown in figure 2 consists of a circular commutator K,
to the blocks of which are made connections 7, 7, from the bights of sections into
which the field magnet coils. are divided, such sections being connected together
into a continuous closed circuit, and each section being wound from end to end of
the core, although in the drawing for convenience of illustration the sections are
placed side by side on the cores.
1
The supplying terminals of the field are connected with the two pivoted
arms a¹, a, on the commutator K, and by moving the said arms upon the com

page_text: mutator, the current is reversed in more or less of the field coil sections, whereby
the strength of the field magnet is varied independently of the armature. As this
apparatus also may effect the reversal of the field magnetism, the current reverser d
is here dispensed with.
In the armature circuit, is an adjustable. resistance ƒ and circuit reverser g
whereby the armature circuit is independently regulated as before.
The reversing switches may be used to make and break the circuits, or additional
circuit controlling switches may be provided.
The arrow-heads in the drawing show the direction of current, in the circuits.
Figures 3, 4, 5 and 6 relate to the single switch for controlling both resistances.
Figure 3 is a diagram of a motor. with its connections and of the apparatus
embodying this part of the invention.
Figure 4 a vertical longitudinal section of the commutator which is employed,
with a diagram of the connections.
. Figure 5 a vertical transverse section of the commutator, and
Figure 6 a plan of the commutator.
E is a shunt-wound electro-dynamic motor. 1, 2 are the line conductors from
which the said motor derives current. f is a series of resistance coils for the
armature circuit, the terminals of which are brought to contact blocks a, a, and e is
a similar series of resistances for the field circuit, connected with contacts b, b.
Situated opposite the contacts a, a, in a line with contacts b, b, is a long contact
block c, connected in the field circuit, and opposite the contacts b, b, in line with
the contacts a, a, is a similar long contact block c¹ in the armature circuit.
The contacts a, a and c are mounted in the form of an arc on an insulating
strip D, and contacts b, b, and c are similarly mounted on strip D¹. The contacts
are preferably of the form shown being supported off from the strip so as to enter
between the jaws of forked contacts h and h¹, which are carried by a metal arm F,
pivoted at f, and working back and forth between the two series of contacts.
To this arm F is permanently connected, one of the terminals of the supplying.
circuit. When the contacts h h¹ are at the highest position in the diagram
figure 3, it will be seen that all the resistance coils a, a, are in the armature circuit,
but there are none in the field circuit. Consequently there is a strong field
magnet and weak armature, when the motor is started by throwing in switch g'.
On then moving the contacts h, h¹, down, resistance is cut out of the armature
circuit, while, as contact h is moving on the long block c, there is no change in the
field circuit. Thus, the armature circuit is gradually raised to the full potential,.
which is reached when the contact h' reaches the lowest of the contacts a. Then,,
to weaken the field and still further increase the speed or power or both of the
motor, the contacts h h¹ are moved further down, and as they pass from one con-
tact 6 to another, resistance coils e are placed in circuit, and the field is gradually
weakened, while the armature circuit is not affected, because contact h¹ is moving.
on the long block o¹. The end of the two long blocks extend opposite each other, so
that circuit is maintained in passing from the armature resistance contacts to the
field resistance contacts.
In practice, these effects are produced by moving the pivoted arm F along the
two series of contacts. The motor is thus made to start slowly and then to
gradually increase its speed up to the maximum. While the motor is running,
its field magnet may be regulated without affecting the armature current, by
changing the position of the moving contacts between contact c¹ and contacts b, b.
The same effect is produced by adjusting first one and then the other of the
regulating devices of figures 1 and 2.
It will be understood, that in the section figure 4 only the field circuit resistance
contacts can be seen. Hence the wire which leads to the armature resistance
contacts is shewn broken off in this figure at l. The arm F is moreover shewn in'
different positions in Fig. 3, Fig. 4 and Figa, 5 and 6.
g is a switch for reversing the armature circuit, and d a similar switch for
reversing the field circuit,

page_text: It is evident, that the apparatus set forth may be employed to regulate the
field and armature circuits of two or more motors connected together.
Figures 7 and 8 are diagrams illustrating that part of the invention which
relates to electric railways.
A, A, represents one track, and B, B, another, of an electric railway line. Each
track has an intermediate rail C, which intermediate rails form one side of the
circuit, while the working rails and the ground form the other side. Both tracks
are supplied with current from a single source D³. In figure 7, upon the
track A, A, are two electro-dynamic motors E. and E'. These motors are shown
as mounted upon separate trucks, which may be trucks of the same car or carriage
or of different cars or carriages of the same train.
In each motor, m is the armature and n the field magnet, and o is a contact
roller for taking current from the intermediate rail. The circuits of the two
motors E, E are as follows;-
A main wire 1 runs from the contact roller o of one motor to that of the other;
and a main wire 2 from a brush resting on the axle of one motor to a similar
brush on the other. Thus, these wires 1 and 2 form the two sides of the circuit
for both motors.
From conductor 1, extends a wire 3, and from conductor 2 a wire 4. Wire 3
runs to conductors 5, 5, which extend each to a terminal of one of the motor field
magnets; and wire 4 is connected to wires 6, 6, which extend respectively to the
other field magnet terminals. Thus, the two field magnets are connected in
multiple arc between wires 3 and 4. A circuit reverser d is connected with wires 3
and 4 so that the current in the field magnets may be reversed, and in wire 3
is interpolated an adjustable resistance e, whereby the current energizing both
field magnets is varied to regulate the strength of the two magnets simultaneously,
without affecting the armature circuit of the motors.
From wire 1 extends also a wire 9, which is connected with wires 10, 10,
extending each to a commutator brush of one of the motors; and from wire 2,
wire 7 extends to wires 8, 8, which go to the other commutator brushes.
The armatures of the two motors are thus placed in multiple arc to each other,
like the two field magnets, and the two armatures are in shunt relation to the two
field magnets. In wires 7 and 9, are placed a circuit reverser g and an adjustable
resistance, whereby the current of the two armatures is regulated and reversed
without affecting the strength of the field magnets. The resistances are shown in
the position for starting the motor, all the resistance being cut out of the field
circuit and the armature resistance being in the armature circuit.
On the track B, B, are motors E³, E³. The main wires 1, 2 are arranged as
before. From one to the other extends a circuit 11, 11 which includes in series the
field magnets of both motors, and also a circuit 12, 12, which includes both
armatures in series. In circuit 11, are placed the adjustable resistance e and
circuit reverser d, whereby both field magnets are simultaneously varied or reversed;
and in circuit 12, are the resistance f, and reverser g, whereby the current of both
armatures is controlled; the regulation of each circuit being independent of that
of the other. As shown in the drawing, there is no resistance in either circuit,
there being thus full potential at the armature terminals, and strong field magnets.
On track A, A, figure 8, are motors E E. From wire 1, a wire 13 extends,
which includes both field magnets in series and returns to wire 2.
And from wire 1, extends also a wire 14, and from wire 2 a wire 15 (including a
part of wire 13). Wire 14 is connected with wires 16, 16, which go to commutator
brushes of the two motors; and wire 15 goes to wires 17, 17, which extend to the
other commutator brushes; thus the two armatures are in multiple are to each
other and in shunt relation to the two field magnets in series.
The circuit reverser g is in. the armature circuit, and reverser d in the field
circuit. In this figure is shown, the form of adjustable resistance already described
herein, wherein the same contact arm F is moved successively along the field
:

page_text: resistance contacts e and the armature resistance contacts f, whereby the armature
may be first increased and the field then weakened after the motor is started.
In this figure, there is no resistance in the armature circuit and a part of the
whole resistance in the field circuit.
The motors E6, E7, on the track B, B of figure 8, have their armatures in series
and their field magnets in multiple arc. The armatures are in circuit 18, 18
extending from 1 to 2, the fields are in multiple arc circuits 21, 21, from wires 19
and 20, which extend from 1 and 2. Circuit controlling devices are provided as
before. The position of the resistances in this case is the same as in that next
preceding.
The circuit reversers may be used to make and break the circuits in which they
are placed. Where several motors are on the same train, the circuits extend from
one car to another, and the circuit controlling devices for the whole train are
placed in one car.
It is evident that any desired number of motors may be connected and arranged
in any one of the several ways above explained. Two motors may be placed on
the same truck of a car or carriage if desired.
The invention has been described with particular reference to simple shunt-
wound motors, but the same methods of, and apparatus for regulation are
applicable to any motor in which the main field is in shunt relation to the
armature, whether or not there be a coil cumulative or differential, in series with
the armature. The term "shunt-wound" in the claims, is intended to cover any
form of machine in which the main field is in shunt relation to the armature.
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
1st A shunt-wound electro-dynamic motor, either stationary or locomotive, or
two or more of such motors connected together, the same being constructed or
combined with suitable devices whereby the said motor or motors may be started
with small difference of potential at the armature circuit terminals and strong field
magnet or magnets, and then the armature circuit potential may be gradually
raised, and then the field magnet or magnets weakened, whether reversers are, or
are not provided for the armature circuit, or for the field magnet or magnets, or
for both.
2nd The switch or commutator for varying both the field and armature circuit
resistances, substantially as herein before described.
3rd The various electrical arrangements and connections for electric railway
motors, shown in figures 7 and 8 and particularly described with reference to those
figures.