Improvements in and Connected with Dynamo Electric Machines and Electric Motors.
Year: 1888

page_text: Date of Application, 2nd Oct., 1888
Complete Specification Left, 27th June, 1859-Accepted, 27th July, 1889
PROVISIONAL SPECIFICATION.
Improvements in and Connected with Dynamo Electric Machines and
Electric Motors.
I, BENJAMIN WILLCOX of 47 Lincoln's Inn Fields, in the County of Middlesex,
Patent Agent, do hereby declare the nature of this invention, which has been
communicated to me from abroad by Charles S. Bradley, of Yonkers, County of
Westchester, State of New York, United States of America, Electrical Engineer, to
bo as follows:-
This Invention relates more especially to the construction of dynamo electric
generators for alternating currents and to the construction of electric motors adapted
for operation with alternating currents, in some cases the generator being self exciting,
and in other cases the motor being actuated partly by a direct continuous current and
partly by the alternating currents. The generator will in some cases be constructed
so as to deliver both a continuous and an alternating current, or either at will, and
both or either at the maximum of efficiency, and when used simply as an alternating
current generator it will havo a capacity for output greatly in excess of the ordinary
alternating current generator.
The armature is by preference of the "ring" type and is wound throughout, the
coils being preferably looped into a closed circuit in the usual manner, so that
connections may be made to the plates of an ordinary commutator. In addition,
connections are carried from four points of the armature circuit distant apart
90 degrees to four insulated collecting rings on the shaft, each two diametrically
opposite constituting a pair. Brushes are in contact with the commutator and from
them connection is made with the field magnet, which may have two poles, or a
multiplicity of poles alternating regularly in polarity. Separate brushes are in contact
with the collecting rings, and each pair can be connected to a separate external circuit.
Such a macbine is self exciting, and will generate and deliver into the said two
separate external circuits two independent alternating currents, one of which will be
one quarter of a phase or wave length behind the other.
A similar machine having the two said external circuits connected to the brushes of
its four collecting rings, will receive such alternating currents and act as a motor with
high efficiency. Its field magnets would be excited by the rectified current delivered
from its regular commutator, or they could be separately excited.
Such a machine is capable of a variety of uses or adaptations. For example, as a
generator, it can be used either as a continuous current machine, or an alternating
current machine, or both. When used as a continuous current generator it is just as
good as if specially made for that purpose; if used as an alternating current generator
it is much better than the machines now generally employed, on account of the large
increase of output possible with a given size of machine. When used as an alternating
current generator, a continuous current for energising the field-magnet can be taken
from the continuous current commutator.
When used as a motor, the machine can be operated with either continuous or
alternating currents, or both, the continuous currents being fed through the rectifying
commutator, and the alternating currents through the two pairs of collecting rings.
The machine may also be utilised as a device for changing a continuous into an
alternating current, or vice versa; or one alternating current into another of different
time-phase. In some cases any pair of brushes may be disconnected or lifted without
interfering with the other circuits. In some cases the machine is to be constructed so
as to have the armature fixed and the field-magnet revolving.
1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in and Connected with Dynamo Electric Machines and
Electric Motors.
I BENJAMIN WILLCOX of 47 Lincolns Inn Fields in the County of Middlesex
Patent Agent do hereby declare the nature of this Invention which has been
communicated to me from abroad by Charles S. Bradley of Yonkers County of
Westchester State of New York in the United States of America Electrical Engineer
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
In alternating current machines as heretofore constructed the generation of current
occurs for practically half the time only, as there are certain points in the revolution
of the armature at which the maximum potential is generated, but between these
points of maximum there are an equal number of points of zero potential. This fact
arises from the modern construction of alternating current machines wherein a
multipolar field magnet is ordinarily used with a drum armature having windings or
coils laid on its external surface. These coils and their arrangement on the drum
must bear a definite relation to the number and angular separation of the pole piece
of the field magnet and the result is that there are a number of blank spaces on the
surface of the armature not occupied by coils and therefore not utilized for the
production of current.
For some purposes it is desirable that the machine should be capable of giving off
either a continuous or an alternating current or both at will and give the maximum
amount of either or both kinds of current with the maximum efficiency.
The objects of this invention are therefore among others to overcome the hereinbefore
mentioned difficulties and limitations, to increase the capacity of output of alternating
current dynamos and to construct a machine which will generate either an alternating
current or a continuous current or both as desired and will give either or both such
currents with the maximum efficiency and output.
In the accompanying drawings which illustrate this invention Figures 1, 2, 3, 4, 5, 6
and 7 represent the characteristics of this invention diagrammatically. Figure 8 is a
simple diagram representing the principle according to this invention of increasing
the capacity for output of alternating current dynamos, as applied to a simple two-
pole machine. Figure 9 is a diagram representing the manner of connecting a closed
circuit armature to give alternating currents according to this invention. Figure 10
is a diagram representing the manner of connecting an armature to give both
continuous and alternating currents while adhering to the fundamental principle.
Figure 11 is a plan view of a dynamo constructed according to this invention.
Figure 12 is a detail view in section showing the continuous current commutator and
the alternating current contact rings and the manner of connecting the same.
Figure 13 is a set of diagrams of the two curves produced by Figure 8 illustrating
the relative periods of alternation produced by the machine arranged according to this
invention and making clear the effect of such on the total capacity of the machine
itself.
N and S represent respectively the north and south pole pieces of the field magnet
which may be excited by a separate current or in any suitable manner.
A is the armature core and B the winding of a simple Gramme ring which will
serve for illustration.
Connections are assumed as being made to the winding at four
equidistant points by the terminals CFD and E arranged in the order named so that
Cand D will be at points diametrically opposite each other and E and F similarly at
points diametrically opposite each other but on a line at right angles to the line
of C and D.
Assuming the armature to be revolving and considering the successive actions
therein according to the well known laws of induction the terminals C and D are, in
the position of Figure 1, at the maximum difference of potential and if they he
connected together directly or through any external resistance current will flow and

page_text: will be maximum for the resistance of the said circuit. The terminals E and F on
the contrary at this moment are each at a common potential and of like sign and
consequently as there is no difference of potential existing between them no current
would flow through any circuit connecting them together.
Figure 9 represents the same armature with the terminals C F D and E connected
to four different contact rings cf de respectively. For the sake of clearness these
rings are shown as concentrically arranged one within the other in the same plane.
Two brushes applied to the contact rings c and d respectively will take off an
alternating current from the armature. This current when the armature is in' the
position indicated in the figure would be at a maximum in one direction or say above
zero; when the armature has revolved through ninety degrees this current from C D
would be at zero; at one hundred and eighty degrees it would be at a maximum in
the opposite direction or say below zero; at two hundred and seventy degrees it
would again be at zero, and so on through each revolution of the armature. If now
two other brushes he applied to the rings e and f respectively a similar and equal
alternating current will be taken from them; but this second current will differ from
the first in time by exactly a quarter of a phase or wave length-that is when the
first current or CD is at a maximum the second or E F will be at zero and conversely
when the first is at zero the second will be at a maximum. This will be clearly under-
stood by inspection of Figures 1 to 7 inclusive. Figures 1 to 4 show the armature
at four different positions each ninety degrees from its predecessor. In Figure 1 the
terminals CD are at a maximum difference of potential in one direction-зay positive
while E F are each of the same potential and the same sign and are therefore at
zero so far as concerns the delivery of current externally. In Figure 2 C D are of
the same sign and potential and therefore at zero while E F are now at a maximum
difference of potential positive. At Figure 3 C D are at a maximum difference of
potential in the opposite direction or negative while E F are at zero and in
Figure 4 E F are now at a maximum difference of potential negative while C D are
The resulting diagrams of output may be graphically shown and Figure 5
represents the poriodic phases of output from the terminals CD while Figure 6 shows
the corresponding phases of output from the terminals E F the dotted vertical lines
indicating each one quarter of a phase or wave length while in the particular relations
of winding and pole pieces shown they will also be indicative of each one quarter
revolution. Thus in the case of any given armature the generation of two independent
currents can be effected each supplementing the other in the manner herein before
described and thus the time wasted during the generation of one is utilized for
the generation of the other and therefore two currents are obtained from the same
machine each of which is practically as great as the machine would generate if used
in the ordinary way. These two currents can be employed for any purpose to which
alternating currents are applicable, and they may be used separately, one being used
to feed one circuit and the other to supply another circuit.
at zero.
In Figure 10 the armature is represented as connected to a rectifying commutator K
in the usual manner and the same winding or armature conductor is connected to
contact rings precisely as in Figure 9.
Figure 11 shows in complete form a dynamo constructed and connected in this way
K being the rectifying commutator and c d e f being the four contact rings. It is
preferred to place the contact rings c d e f beyond the bearing L as represented in
Figures 11 and 12 in order that the bearing shall not be placed too far out on the
shaft. In this case the ring C is connected to one commutator strip while the ring D
is connected to the commutator strip diametrically opposite; and the rings E and F
are connected respectively to the two commutator strips carrying positions ninety
degrees either way from the strips to which the rings and Dare connected. The
connections from the commutator strips to the rings are carried through the shaft
which is made hollow for that purpose as shown in Figure 12. With such construction
and arrangement on revolving the armature of the machine a continuous current may
be taken from the commutator K by suitable brushes in the usual manner one
alternating current may be taken from the rings C and D and another alternating

page_text: current may be taken from the rings E.and.F; but as herein before explained this
second alternating current will be a quarter of a phase behind the current taken from
the rings CD. These currents may all be taken at the same time if desired and their
relative proportions to each other will depend upon the external resistances in the
threo circuits, in accordance with well known laws.
The advantage of a dynamo constructed according to this invention is that it may
be used either as a continuous current machine or as an alternating current machine
or both.
When used as a continuous current generator it is just as good as if
specially made for continuous currents. If used as an alternating current generator
it is much better than the machines now generally employed on account of the large
increase of output possible with a given size of machine. There is thus provided a
dynamo which can be used for either purpose; and at any time it is desired to change
the alternating current system to the continuous or vice versa it can be done without
trouble.
Another advantage from the foregoing construction lies in the fact that when the
machine is used as an alternating current generator a continuous current for energising
the field magnets can be taken from the continuous current commutator-
words the machine is in that event self exciting.
or in other
Any approved form of armature can be connected up according to this invention.
For example a drum armature may be connected in a manner precisely similar to that
which I have shown and described for a Gramme ring. It is preferred to employ
those forms of armature in which the winding is so constituted as to form what is
known as a
"closed circuit" in preference to an armature whose winding is in the
form of one or more open ended coils because the former are generally of higher
efficiency and output and are besides much more conveniently applicable to the purpose
of this invention.
It is obvious from inspection of Figures 10 and 11 that this machine may be used
as a motor as well as a generator and that it may when so used be fed or actuated
either by continuous or by alternating currents or by both the continuous currents
being fed through the brushes of the rectifying commutator K and the alternating
currents being supplied through the contact rings c d e f. It is also obvious that the
machine may be used as a device for changing a continuous current to an alternating
current or vice versa or one alternating current into another of different time phase.
The former would be accomplished by feeding the machine with a continuous current
by the brushes on the rectifying commutator and an alternating current or two
alternating currents can be taken from the machine through the brushes in contact
with the rings c d e and f. Where alternating currents are to be delivered to the
machine and by it commutated into continuous currents the alternating currents will
be delivered in the first instance through the rings c d e and fand the rectified
continuous current will be taken off by the ordinary bearing on the commutator K.
Where it is desired to use the machine to change one alternating current into another of
different time phase the primary current is sent into the machine through the rings c d
for example and from the rings efthere can be collected an alternating current
whose time period will differ by one quarter phase from the original or primary
current. When it is desired to use the machine so constructed for any purpose which
does not involve the simultaneous use of both sets of brushes, the set which is not
wanted is simply lifted out of contact with its rings or commutator as the case may be.
For example if the machine is to be used as a continuous current generator only the
brushes are applied to the rectifying commutator K and all brushes bearing on contact
rings c d e f are lifted out of contact with such rings so that there will be no circuit
except the external circuit from the commutator K through its own brushes.
Conversely when the machine is used as a generator for alternating currents alone
the corresponding brushes are placed in contact with their rings c d e f and the
brushes, bearing on the rectifying commutator K are lifted out of contact therewith if
the field magnets are energised from another source; but if the machine is to be self
exciting the brushes are left on the commutator K and connected in the usual manner
with the energizing coils of the field magnet and in this case the resistance in the field

page_text: magnet circuit will be made high enough to absorb only the percentage of the total
current proper for the purpose of charging the fields.
Many other modifications in the manner of use of such a machine will readily
suggest themselves to one skilled in the art to which this invention appertains and the
same need not be more specifically referred to herein. In order to avoid confusion I
use the term "current leading device" as expressive of either rings and brushes or
commutator and brushes or both or other connecting devices according to the use and
manner of use of the machine.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. An alternating current dynamo electric machine having generative conductor,
in combination with two pairs of current leading devices said pairs being respectively
connected to the generative conductors so as to collect two independent alternating
currents one of which has its time phase substantially one fourth of a wave length
or period behind the other.
2. An alternating current dynamo electric machine constructed with its generating
circuit closed in combination with two pairs of current leading devices the pairs being
respectively connected to said generating circuit so as to collect two currents
independently of each other and substantially one fourth of a phase apart in their
relative time periods.
3. An alternating current dynamo electric machine constructed with its generating
conductor constituting a closed circuit and having two pairs of independent current
leading devices one pair connected into said closed generating circuit at mutually
opposite points and the other pair connected into said generating circuit at inter-
mediate points also mutually opposite each other.
4. A dynamo electric machine having an armature provided with a current
rectifying commutator and brushes therefor and two pairs of current leading devices
the pairs being respectively connected to the armature winding at alternating points
of the same so as to lead off two alternating currents independent of each other.
and substantially one fourth of a phase apart in their respective time periods.
5. An electro motive device consisting of a field magnet and a rotating armature
provided with a rectifying commutator and brushes therefor through which current is
received into the armature and rotation produced, in combination with two pairs of
current leading devices respectively connected to the armature winding at alternating
points and so arranged relatively as to lead off two independent alternating currents
substantially one fourth of a phase apart in their relative time periods whereby a
continuous current may be transformed into two independent alternating currents.
6. An electro motive device consisting of a field magnet and a rotating armature
provided with a rectifying commutator and brushes therefor, in combination with two
pairs of current leading devices, each pair independently connected to said commutator
at respectively alternating points and the two pairs adapted to receive and deliver to
said armature two independent alternating currents of different plase from corre-
sponding external circuits.
7. An electro motive device consisting of a field magnet and a rotating armature
provided with a rectifying commutator and brushes therefor in circuit with the field
magnet coils in combination with two pairs of current leading devices-such for
instance as contact rings and brushes each pair independently connected to the
armature winding at alternating points of the same substantially as described whereby
the two pairs of current leading devices are adapted either to receive and deliver to
said armature two independent alternating currents of differing phase from corre-
sponding external circuits or to receive from one external circuit a single
alternating current, change its time period and deliver the same into another external
circuit.
8. A self exciting alternate current dynamo electric generator having a rectifying
commutator and brushes connected to its field magnet circuit and having two pairs of

page_text: collecting rings and brushes adapted to deliver two independent alternating currents
externally the generating circuit being common to both the commutator and collecting
rings.
9. A rotary electric motor consisting of a field magnet and armature and two pairs
of current leading devices-such for instance as contact rings and brushes-the
respective pairs being independently connected into the armature winding at
alternating points of the same and arranged for connection with two independent
external circuits.
Data shoh Love of Lu 1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.