Improvements relating to the use of Electric Motors and to the Regulation or Control of Machinery operated thereby.
Year: 1890

page_text: Date of Application, 9th Sept., 1890-Accepted, 7th Feb., 1891
COMPLETE SPECIFICATION.
[Communicated from abroad by THE THOMSON-HOUSTON INTERNATIONAL
ELECTRIC COMPANY, of No. 620, Atlantic Avenue, Boston, Massachusetts,
United States of America.]
Improvements relating to the use of Electric Motors and to the
Regulation or Control of Machinery operated thereby.
I WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings in the County of Middlesex, 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 :—
The invention consists in providing for any machinery which it is desired to
operate by electricity with varying speed and power two electric motors which are
connected to the machine so as to co-operate in driving it.
As it is well known that the regulation of an electric motor depends upon the
relation between the direct and the counter electro motive force, it becomes
necessary on a constant potential circuit that a motor must be regulated in its
speed, either by varying its counter electro motive force with relation to the speed,
or else by inserting a resistance to compensate for any decrease of counter electro
motive force when the said counter electro motive force corresponds with the speed
of the motor and cannot be varied independently thereof.
In the method forming the subject of this invention the two armatures constitute
each a source of electro-motive force which may be placed either in series or in
multiple arc, so that the total electro motive force of the motors may be varied
independently of the speed of the driven mechanism and no artificial resistance be
required.
:
The invention therefore consists in a method by which different degrees of speed
in the driven mechanism may be obtained by, First: placing the two motors in
series; Secondly regulating the counter electro motive force of one or both of
the motors by changes in the field magnet strength so as to produce a higher rate
of speed; Thirdly short-circuiting one motor after its counter electro motive
force has been reduced to a point where the short-circuiting may be accomplished
without sparking; Fourthly: connecting the two motors in multiple are with their
normal field magnet strength; and Fifthly regulating the field magnet strength
of one or both of said motors to obtain the highest rate of speed. More or less of
these steps may be taken as desired.
:
The invention is illustrated in the accompanying drawings, in which,
Figs. 1, 2, 3 and 4 are diagrams illustrating the various modifications of the
invention.
Fig. 5 is a diagram illustrating apparatus that can be used in practising the
invention.
Fig. 6 is a diagrammatic view of a modified form of apparatus.
Fig. 7 is a diagram of the circuits in which is shown a switch mechanism of
still another form of construction that may be used in practising the invention.
Fig. 8 is a plan view of the switch mechanism whose circuits are diagram-
matically illustrated in Fig. 7.
Fig. 9 is an end view of the switch cylinder shown in Fig. 8.
Fig. 10 is a perspective view of one of the spring contact discs of the switch
cylinder.
Referring to Fig. 1 of these drawings X and Y represent the two main lines of
a constant potential circuit A and B represent two electric motors. A' and B'
represent the field magnets, and A, B, represent the armatures of the respective
motors. In Fig. 1, these motors are shown connected in series with switches for

page_text: changing connections us may be necessary in carrying out the method. A switch
is also provided for cutting out more or less of the field magnet coils of motor A.
The circuit may be traced from line X to switch b, to contact to mingnet A¹ of
the motor A, and by switch e, m, to the second motor B. The two motors will
then be in series and adapted for the lowest rate of speed. By operating switch
lever, more or less of the oils of A' will be thrown out of circuit. This will
tend to increase the speed by deerensing the total counter electro motive force, of
the two motors. may be moved until substantially all of the coils of A¹ are cut
out when the counter électro motive force of A will be substantially reduced to
zero, and it may then be safely short-circuited without producing any are at the
contact. This will be accomplished by turning the switch onto the contact
plate m, when only the motor B will be actually in circuit.
The method which has thus far been described is one which may be employed
in any instance where it is desired to remove one motor from series connection
with another motor without producing sparking at the contact as would be the
ense where an active armature is suddenly short-circuited. The next step in the
method of regulating will be to place motor A in multiple are connection with
motor B with its field magnet restored to its full strength. This will be
accomplished by moving switch to the position shown in dotted lines where the
circuit of A is entirely interrupted. The switch e will then be turned to contact
plate and the switch turned to contact plate a.
The switch arm may then be rapidly brought to contact, where it will give
the same connection as is obtained by . For the final step motor A alonë or
motor B also may again have its field 'magnet strength reduced to obtain a greater
speed than would be possible with the two motors in multiple-are with their full
field magnet strength.
In Fig. 2 substantially the same arrangement of eirenits is shown. The
switch 6, however is omitted, its function being performed by moving the arm b
onto a supplementary contact which is connected both to the switch d and to the
outer field magnet coil of A.
In Fig. 3 another arrangement for accomplishing the same result is illustrated.
In this instance however, the motor A is short-circuited by moving the switch b
onto the contact g, and it is then thrown into multiple-are connection by a further
movement of the switch 6 so as to connect the plates g² m². Fig. 4 shows the
same arrangement as Fig. 2 except that the switch d has a connection to main
line X independent of the contact piece g
Fig. shows how the connections illustrated in the previous figures may be
successively made by a single movement of the switch, in other words the switch
arm is provided with an operating connection to switches and e, so that they
may be turned automatically after the switch has reached the point where it
has cut on the whole of field magnet A'. In this figure also is shown the two
arinatures connected by a belt j, which indicates that they are both connected to
the same driven mechanism so as to co-operate in their action upon it. In the
position of the switch shown in the figure, both motors are in series, the arm bis
then moved so as to short-circuit successive sections of magnet A', and then as it
passes from plate 9 the radial projection throws the connected switches c, d,
onto the plates, m, respectively. The two motors will then be in multiple-arc.
Fig. 6 shows an arrangement by which the field magnet strength of motor A
is reduced by a resistance, which is gradually withdrawn from a shunt around
the field magnet. In this arrangement the arm b gradually short-circuits the
field magnet A, then cuts it out of circuit and by coming in contact with pin o² it
moves the arm Bª along with it until the latter contacts with /, while the former
rests upon m and g².
This produces the same results accomplished by the arrangements previously
described. For practical use, for instance, in the controlling of electric railway
motors, there has been devised the apparatus illustrated in Figs. 7, 8, 9 and 10.
This consists of a cylinder switch made up of placing a number of discs l' upon the

page_text: same shaft so as to be operated together. Each of these discs consists of an
insulating centre upon the periphery of which are placed a series of projections ³,
spaced so as to make the desired connections when brought into contact with the
respective stationary contact pieces. One of these is illustrated in Fig. 10 and
consists, of two plate springs rivetted to a conducting block, and adapted to extend
into the path of the projections, so as to be separated and press upon the
opposite sides of the said piece making thus a good electrical connection therewith.
The said stationary contacts are connected to various parts of the circuits as will
be seen at the top of Fig. 7 where they are marked a¹, a², a³, ete. a', and u", are
connected to the two terminals respectively, the former being also connected to the
end coil of the field magnet of motor B. a is connected to an intermediate point
of the said field magnet and a³ to its opposite terminal.
a is connected to one terminal of the field magnet of motor A, a to an intermediate
point of the said magnet and a to the opposite terminal. a', *, aº, and a", are
connected respectively to the four terminals of the motor circuits.
The lower part of Fig. 7 indicates the connections which are established between
the said stationary contacts a, a, a, etc. by means of the projections g, as they are
turned by shaft C. The Figures 1, 2, 3, el. on the left of Fig. 7 indicate the
successive positions of the switch, and consequently the different conditions. There
are eleven different arrangements of the connection shown, although the invention
is not confined to this number.
The same letters in different figures represent corresponding parts.
Two similar sets of contacts may be arranged in reverse order upon cach half of
the switch cylinder permitting the same order of connections to be established in
whichever direction the cylinder may be rotated, the currents through the armature
being reversed with the opposite directions of rotation. This is shown in Figure 9,
but in the diagram of Figure 7 only the half for simplicity.
represent metallic bell crank levers pivoted at the angle and held by springs s,
as shown. Their function is to delay the breaking of the circuit by being dragged
away from the teeth ³ by the contact springs from which they are suddenly released
with a snap action so as to secure a more certain breaking of the are that is formed
at the time of breaking.
Position one is the zero point, the only connection being a short-circuit around
a portion of each field magnet for the purpose of absorbing the extra current upon
the breaking of the motor circuit. In position 2 the armatures and fields of both
machines are connected in series. In position 3 the same connections are shown as
in position 2 with the exception that a portion of the field of each motor is short-
circuited. Position throws the fields of the motors in multiple, the armatures
remaining in series. Position 5 short-circuits a portion of each field winding.
Position 6 detaches one of the fields (that of B) from the circuit, leaving both of
the armatures in series with one field. Position 7 is the same as position 6 with the
exception that fields are substituted, each for each, in order that the changes in the
field magnet strength may not always be made upon one magnet only. Position 8
cuts out entirely one of the motors, (in the diagram motor A) leaving one-half of
the field of B in circuit.
It should be mentioned that in passing from 7 to 8 the distance between contacts g
and being less than the width of the contact strips, the armature of the motor A
is momentarily short-circuited.
Position 9 is the same as position 8 with the motors interchanged, each for
each. In position 10 both motors are in multiple, and in position 11 sections of
the motor fields are cut out for producing the final degree of speed.
It will be seen that steps 6 and 7 produce no difference in speed, likewise steps 8
and 9. The mutual substitution of the motor in these instances for the purpose of
more nearly equalizing the total amount of work which each motor is called upon
to do, that is equalizing the heat developed in each motor should one motor at a time
be called upon to do an excessive amount of work.

page_text: It is evident that the method of connection may be very greatly varied without
departing from the principles of the invention: for instance more than one extra
coil on the field circuit could be used where but one is shown in this dingrain. This
method of coupling may also be applied to more than two motors.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondent. E declare that what 1 claim is : –
1. The method of removing an electric motor from series connection with another
motor connected to the same mechanism, which consists in reducing the counter
electro motive force in the armature of the motor to be removed, and then short-
circuiting the said motor.
2. The method of removing an electric motor from a cirenit in which it is in
series with another motor geared to the same load, which consists in reducing the
counter electro motive force in the armatures of the motor to be removed, and then
short-circuiting the said motor.
3. The methiol of removing an electric motor, from the circuit in which it is in
series with another motor connected to the same mechanism, which consists in
reducing the counter electro motive force of the motor to be removed by changing
the field magnet strength of the said motor, and then short-circuiting it.
4. The method of controlling electrically propelled mechanism which consists in pro-
viding two motors which are commerted to aid mechanism, so as to co-operate in driving
it, and then regulating the two motors, by First, placing them in series for a slow
speed; Secondly, increasing the speed by changing the field magnet strength of one
or both motors, and Thirdly, short-cireniting one motor after the counter electro
motive force in its armature has been reduced to a safe degree.
5. The method of controlling electrically propelled mechanism, which consists
in providing two motors which are connected to said mechanism so as to co-operate
in driving it and then regulating the two motors by First, placing them in series for
a slow speed: Secondly increasing the speed by changing the field magnet strength
of one or both motors: Thinlly, short-circuiting one motor after the counter clectro
motive force in its armature has been reduced to a safe degree; and Fourthly,
placing the two motors in multiple are connection.
6. The method of controlling electrically propelled mechanism which consists in
providing two motors which are connected to said mechanism so as to co-operate in
driving it and then regulating the two motors by First, placing then in series for n
slow speed Secondly, increasing the speed by changing the field magnet strength
of one or both motors; Thirdly, short-circuiting one motor after the counter electro
motive force has been reduced to a safe degree; Fourthly, placing the two motors
in multiple are connection; and Fifthly, increasing the speed still further by varying
the field magnet strength of one or both of said motors after they have been placed
in multiple are connection.
7. The method of changing two motors from series to multiple are connection
which consists in reducing the counter electro motive force in the armature of one
or both of said motors, short-circuiting one motor when its counter electro motive
force has been reduced to a safe degree, and then connecting the two motors in
multiple are.
8. The method of controlling electrically operated mechanism, which consists in
providing an electro motive apparatus having two sources of counter electro motive
force, connecting these sources in series, reducing the electro motive force of one of
said sources and short-circuiting it, and then connecting the two sources in multiple
are with their normal electro motive force.
9. The method of controlling electrically operated mechanism, which consists in
providing an electro motive apparatus having two sources of counter electro motive
force, connecting these sources in series, reducing the electro motive force of one of
said sources and short-circuiting it, and then connecting the two in multiple are

page_text: with their normal electro motive force, and finally reducing the counter electro
motive force of one or both of the said sources for the last degree of regulation.
Dated this 9th day of September 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.