Improvements in Means for Varying the Speed of Electrio Direot Current Motors.
Year: 1896

page_text: Date of Application, 31s! Dec., 1896
Complete Specification Left, 16th Aug., 1897-Accepted, 2nd Oct.. 1897
PROVISIONAL SPECIFICATION.
Improvements in Means for Varying the Speed of Electrio Direot
Current Motors.
1, HENRI PIEPER Fils, of Rue de Bajards, Liege, in the Kingdom of Belgium,
Managing Director, do hereby declare the nature of this invention to be as
follows:-
This Invention has for its object to enable the speed of electric motors driven
by means of direct currents, to be altered according to requirement, and it consists
in the employment for this purpose of meaus for enabling the armature of the
motor to be acted upon by different current tensions in accordance with the
speed required. These different teusions are obtained by the use of multiple con-
ductors, or wires, as the supply system, in combination with means such as com-
mutators, or their equivalents, for varying the connection between the armaturo
of the motor and any two wires of the supply system according to the speed
required.
The simplest form of the improved arrangement is that in which the motor is
fed by means of a three wire, or multiple wire system.
Fig. 1 of the accompanying drawings illustrates diagrammatically this arrange-
ment as applied to a motor, the excitation of which is produced by means of
a shuut, and maintained constant.
a, b, and c, are the three wires of the supply system, A is the armature of the
motor, E the exciting coil of the same, and U a commutator, or switch, for con-
necting the armature with two of the wires a, b, c.
When, by the switch U being in the position shewn in full lines, the armature
is connected with the wires a and b between which there is a certain difference
of potential V, which is maintained constant, the motor will be driven at a certain
speed, and if the switch U be moved to the position shewn in dotted lines, the
motor will be couneoted with the wires a and e, between which the difference of
potential is double i.e., 2V and then the speed of the motor will be nearly
doubled.
The arrangement may of course be combined with one in which the magnetic
field is altered through the medium of suitably varied ampere-windings in the excit-
ing coils of the motors, employing either two or more motors, which are successively
connected in parallel and in series; or with one where there is one armature only
which is provided with two or more separate windings, and combined with a number
of collectors which are successively connected in parallel and in series; the excitation
being produced by multiple poles, the number of which is caused to vary in
accordance with the varied connection of the exciting coils.
Figure 2 represents diagrammatically an arrangement enabling three different
tensions and consequently three different velocities of the motor to be obtained,
the three wire system employed being somewhat different from the ordinary one.
Between the wires a and b there exists a difference of potential V which is
maintained constant, and between the wires b and c there is a potential difference Vi

page_text: which is constant also, but differs from V. Besides, the circuits of the current
generators are so disposed that between a and c there occurs a difference of poten-
tial VV. According therefore as the motor is connected by means of the
switch U or its equivalent to the wires a b, or b c, or a c, three different speeds will
be obtained in the motor corresponding to the thrco different tensions. These three
speeds may be utilized in conjunction with any of the other methods for varying
the speed of electric motors by means of variations in the magnetic field or by
variations in the armature windings.
The switch U is for instance shewn as consisting of two blocks each with a set
of three contacts 1, 2 and 3 connected with the wires as shewn, there being a
contact arm for each set of contacts, these arms being connected by a link and
electrically isolated from each other. When the arms are on the contact pieces 1, 1
the motor is connected to the wires be, and when the arms are on the contact
pieces 2, 2, it is connected to the wires a b, and when the arms are on the contact
pieces 3, 3, it is connected with the wires a c.
Instead of three conductors any number of conductors may be used, with equal or
unequal, tensions kept up between every two adjacent wires. Or the arrangement of
the current generator circuits may be such as to enable either sums of tension
or differences of tension to be obtained between wires that are not immediately
adjacent, taking them two and, two, three and three, or in some such order of
classification; by which means a large number of different tensions, and correspond-
ing velocities; may be produced in one and the same motor supplied with energy
from a number of wires of one and the same supply system.
The advantage of such an arrangement resides in the fact that it enables a wide
range of different speeds to be readily secured for one and the same direct current
motor, the working capacity of such motor being thus increased without un-
necessary loss of energy in the resistances and, moreover, by means of apparatus
capable of being very readily manipulated. The improved arrangement can very
conveniently be combined with any of the arrangements already known.
The supply systems hereinbefore described may be fed from separate dynamos,
which are situated each between a pair of conductors, and connected as usual, and
mounted on one common shaft, or on several sliafts. Or the conductors may be
supplied with current from a single dynamo provided with several windings and
commutators, each commutator serving for a pair of conductors; or else from a
single dynamo constructed' for the highest tension and connected with those con-
ductors between which such tension is to be produced; while the remaining con-
ductors are connected with a dynamo or dynamos provided with a coil or coils and
commutator or commutators, in which case sucli motor, or motors, runs, or run,
idle to operate as compensation-transformers.
1000
⚫ JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents..
COMPLETE SPECIFICATION.
Improvements in Means for Varying the Speed of Electric Direct
. Current Motors.
15
I, HENRI PIEPER Fils, of Rue de. Bajards Liege, in the Kingdom of Belgium,
Managing Director, 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 has for its object to enable the speed of electric motors driven

page_text: by means of direct currents, to be altered according to requirement and it consists
in the employment for this purpose of means for enabling the armature of the
motor to be acted upon by different current tensions in accordance with the
speed required. These different tensions are obtained by the use of multiple con-
ductors or wires as the supply system in combination with means such as switches
or their equivalents for varying the connection between the armature of the motor
and any two wires of the supply system according to tlie 'speed required.
I will describe my Invention with reference to the drawings accompanying the
Provisional Specification.
The simplest form of the improved arrangemont is that in which the motor is
fed by means of a three, wire system.
Figure 1 of the drawings illustrates diagrammatically this aringement
as applied to a motor, the excitation of which is produced by means of a shunt
and maintained constant.
a b and c are the three wires of the supply system, A is the armature of the
motor, E the exciting coil of the same and U a commutator or switch for con-
necting the armature with two of the wires a b c..
When, by the switch U being in the position shewn in full lines, the armature
is connected with the wires a and b between which there is a certain difference
of potential V, which is maintained constant, the motor will be driven at a certain
speed, and if the switch. U be moved to the position shown in dotted lines, the
motor will be connected with the wires a and c, between which the difference of
potential is double s.e., = 2 V, then the speed of the motor will be nearly doubled.
"The arrangement may of course he combined with one in which the magnetic
field is altered through the medium of suitably varied ampere-windings of the excit-
ing coils of the motors, employing either two or more motors, which are successively
connected in parallel and in series; or with one where there is one' armature only
which is provided with two or more separate windings, and combined with a number
of collectors which are successively connected in parallel and in series; the excitation
being produced by multiple poles; the number of which is caused to vary in
accordance with the varied connection of the exciting coils.
Figure 2 of the drawings represents diagrammatically an arrangement enabling
three different tensions and consequently three different velocities of the motor to be
obtained, the three wire system employed being somewhat different from the
ordinary one.
Between the wires a and b there exists a difference of potential' V which is
maintained constant, and between the wires & and there is a potential difference V'
which is constant also, but differs from V. Besides, the circuits of the current
generators are so disposed that between a and c there occurs a difference of poten-
tial VV. According therefore as the motor is connected by means of the
switch U or its equivalent to the wires a b, or be, or a c, three different speeds will
be obtained in the motor corresponding to the three different tensions. These three
speeds may be utilized in conjunction with any of the other methods for varying
the speed of electric motors by means of variations in the magnetic field or by
variations in the armature. windings.
The switch U is for instance shewn as consisting of two blocks each with a set
of three contacts 1, 2 and 3 connected with the wires as shewn, there being a
contact arm for each set of contacts, these arms being connected by a link and
electrically isolated from each other. When the arms are on the contact pieces 1, 1,
the motor is connected to the wires bc, and when the arms are on the contact
pieces 2, 2, it is connected to the wires a b, and when the arms are on the contact
pieces 3, 3, it is connected with the wires a c.
Instead of three conductors any number of conductors may be used, with equal or
unequal, tensions kept up between every two adjacent wires. "Or the arrangement of
the current generator circuits may be such as to enable either sums of tensions
or differences of tension to be obtained between wires that are not immediately
adjacent, taking them two and two, three and three, or in some such order of

page_text: classification; by which means a large number of different tensions and correspond-
ing velocities may be produced in one and the same motor supplied with energy
from a number of wires of one and the same supply system.
The advantage of such an arrangement resides in the fact that it enables a wide
range of different speeds to be readily secured for one and the same direct current
motor, the working capacity of such motor being thus increased, without un-
necessary loss of energy in the resistances and, moreover, by means of apparatus
capable of being very readily manipulated. The improved arrangement can very
conveniently be combined with any of the arrangements already known:
The supply systems herein before described may be fed from separate dynamos,
which are situated each between a pair of conductors, and connected as usual, and
mounted on one common shaft, or on several shafts. Or the conductors may be
supplied with current from a single dynamo provided with several windings and
commutators, each commutator serving for a pair of conductors; or else from a
single dynamo constructed for the highest tension and connected with those con-
ductors between which such tension is to be produced, while the remaining con-
ductors. are connected with one or more dynamos provided with one or more coils
and commutators, in which case such motor or motors runs or run idle to operate
as compensation-transformers.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. For feeding electric motors with direct current the combination with electric
supply systems comprising three, four or more conductors with equal tensions
between two adjacent conductors, of a switch for enabling the motor to be fed from
any two of the conductors so as to obtain different tensions and consequently,
different speeds in the motor according to the particular conductors to which it is
connected by the said switch substantially as hereinbefore described.
2. For feeding electric motors with direct current a system of three, four or more
conductors with different tensions between two adjacent conductors as regards the
totality of pairs of adjacent conductors or a part of said pairs, so that the tension
between any two of the conductors of the system can be made equal to sums or
differences of tension between adjacent conductors substantially as and for the
purpose stated:
3. For feeding electric motors with direct current, the combination with the
electric supply systems comprising three, four or more conductors with unequal
tension between adjacent conductors, of a switch enabling the motor to be fed from
any two of the conductors so as to provide for a wide range of different tensions
and consequently of speed, substantially as described.
Datedithis 16th day of August 1897
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.