Dynamo-electric Machines.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Dynamo-electric Machines.
I, STANLEY CHARLES CUTHBERT CURRIE, Electrician, a Subject of the Queen of
Great Britain, now residing in Philadelphia, Pennsylvania, U.S.A., do hereby declare
the nature of my invention for DYNAMO-ELECTRIC MACHINES, and in what manner the
same is to be performed; to be particularly described and ascertained in and by the
following statement :-
My invention consists in a new way of winding the armatures of dynamo-clectric
machines, and of governing such machines, whether they be generators or motors, by
throwing one or more commutator-brushes or brush-circuits into or out of action.
With the ordinary winding, such as that of the Gramme ring, and its well-known
modifications, in the event of a brush being removed from the commutator, or its
circuit being opened, the corresponding armature-winding or coil would have no
current, or a reduced current: Such reduced current being less than the current in
the remaining closed-circuit or circuits of the armature; in either of which cases
there will be an uneven magnetic influence in or on the armature.
With my improved winding the removal of a brush takes off or reduces current
from a portion of the winding of the armature, in such manner that each pole is
equally and evenly influenced. I wind the armature as follows: Starting from one
commutator-bar, the wire is wound upon the armature, making as many loops thereon
as there are poles, and is finally connected with the wire leading from the next com-
mutator-bar, which latter wire is similarly wound upon the armature. That is to say,
in my system, starting from a commutator-bar, there is a complete winding or series
of loops equal to the number of poles of the armature, over the entire armature,
without intermediate connection to commutator-bars, as has heretofore been the
custom. The winding is such that, in the event of one or more of the brushes being
lifted from the commutator, such brushes as remain in contact (of course there will
never be less than two) will cause a portion of wire in the armature to be active.
That is to say, either giving out current, in the case of a generator, or receiving it, in
the case of a motor; and in all cases the current is evenly distributed over the
surface of the armature in such manner that each pole is equally influenced. The
windings between the commutator-bars may be side by side, or arranged one on top
of another, or some side by side and others on top, as will be apparent from the
following description :
In the accompanying drawings-
Fig. 1 is a diagrammatic perspective view of one manner of winding a four-pole
armature.
•
Fig. 2, an end view of a four-pole armature in diagram, showing the winding more
fully.
Figs. 3, 4, and 5, end diagram views of four-pole armatures, showing another
manner of winding, according to my invention.
Fig. 1 illustrates the invention in its simplest form. For the sake of illustration,
only eight sections on the commutator are shown, and only one thickness of wire on
the surface of the armature; that is the windings are side by side. The armature has
four poles. Starting from the commutator-bar 1", the wire is wound on the drum in
a zig-zag form. First, back to the rear end of the armature, across the rear end, then
forward, across the front end, again back-and so on. After crossing four times (the
armature shown being a four-pole armature) the end finishing at x, is connected to
the second commutator-bar 2ª, at a¹, and the wire is again wound as before, and
connected with the third commutator-har 1b, and so on until the whole drum is
covered. The course of the wire starting at 1ª, is indicated by the arrows and the
letter a, and the course of the wire starting from the second bar 2*, is indicated by

page_text: the arrows and the letter a¹. It will therefore be obvious that the circuit between
any two brushes is evenly distributed over the entire armature.
As
In Fig. 2 all the connections for a four-pole armature and a commutator of eight
bars have been shown. Three brushes are illustrated, one being positive and the
other two negative, as marked. The view-which is a mere diagram is looking at
the end of the armature; the four poles of the field are indicated, 12", 1b 2b, 1° 2°, 1ª 24,
represent the commutator-bars and their corresponding wires, and the commutator is
divided into quadrants, A. B. C. D. The wires are shown by the circles around the
armature periphery, lettered to correspond with the commutator-bars. The dotted
lines joining circles and running below them represent the crossing of the wires at
the back end of the armature; and those solid lines above or outside of circles
represent the crossing of the wires at the front end of the armature. It may be
assumed that the armature is that of a motor; that current entering by the positive
brushes and leaving by the negative brush. Those circles shaded with circular lines
indicate the wire in which the current is supposed to be coming towards the observer,
and those shaded by cross-section lines indicate the wires in which the current is
flowing away from the observer. Those unshaded have no current passing in them.
The commutator is divided into quadrants, each having two commutator-bars.
an illustration, and clearly descriptive of all, the wire starting from the commutator-
bar 1" will be traced. It passes from the commutator 1" to the circuniference of the
armature, being there indicated by the unshaded circle 1ª; then along the armature
to its rear end, then across its rear end, as indicated by the dotted line a', then to the
front of the armature at 1ª, then across the front end of the machine, as indicated by
the solid curved line a², then to the rear of the armature, again across its rear end by
the dotted line a³, then to the front to 1a, and finally by the straight line x, to the
wire 2ª, connected with the second commutator-bar 2. In like manner the winding
between any other two commutator-bars may be traced. Obviously all of the poles
are equally affected by the current passing in any one winding, between any two
commutator-bars. By throwing one of the positive brushes out of action, that is, out
of the contact with the commutator-ring, opening its circuit, or introducing
resistance into its circuit, there will of course be proportionately less current
delivered to the armature in case of a motor, or taken from it in case of a dynamo,
and this diminution of current will be felt at each pole of the armature equally. I am
therefore enabled to effectively regulate the capacity of either a motor or generator
by throwing one or more of its brushes into or out of action.
In Figs. 3, 4, and 5 I have shown a larger number of commutator-bars and the
wires forming the windings of the quadrants are to be superposed, one upon another.
Referring to Fig. 4, the wire b, of the commutator-bar 1, is carried to rear end of
armature, across the end to 61, then forward, then across the front end to 63, then back
and across the end to 63, then forward to 64, where it joins wire running from second
commutator-bar 2. When all the wires of the first quadrant of the commutator,
whose bars are numbered from 1 to 13, inclusive, have been similarly wound, there
will be one complete layer over the entire circumference of the armature, as shown in
Fig. 3. And when the wires of the remaining quadrants are wound, there will be
four layers upon the armature.
In Fig. 5, 1 have indicated the four layers of the winding. That is, the wires
forming the windings between the commutator-bars marked from 1" to 13, inclusive,
form one complete layer on the armature: The wires of the next quadrant, the bars
of which are marked 1° to 13, form another complete layer on the armature, which
is wound on top of the first layer; and the remaining quadrants have their windings
arranged in the same manner; of course the last wire of one layer is connected to
the wire leading from the first commutator-bar of the next section or quadrant. In
this figure I have only illustrated by lines marked y, the connection of each wire as it
leaves its commutator-bar.
It will now be seen how materially different this winding is from any heretofore
known, and the difference is found in the fact that the wire starting from any one
conmutator-bar forms a complete system over the whole armature, and is not

page_text: connected at any intermediate point with any other commutator-bar, until its complete
circuit of the armature has been accomplished, and it is then connected with the wire
leading from the commutator-bar adjoining that one from which the wire started.
Of course all the positive brushes are connected, and all the negatives brushes are
connected, and, by throwing out one or more brushes, or varying its circuit, the
capacity of the machine may be regulated. That is to say, in Fig. 5, where there are
two positive brushes and two negative brushes, I may first throw out a positive
brush, which will affect equally all the poles of the armature, and I may then throw
out a negative brush, which will also affect all the poles of the armature.
If two quadrants be thrown out of action, a portion of the windings covering the
entire surface of the armature will be practically thrown out, and the magnetic
influence of the current equally diminished opposite each pole of the machine.
Obviously the improvements are not restricted to cylinder armatures, or to the
Gramme winding, but are applicable to multipolar machines of any character.
In the case of a dynamo, the winding insures equal potential at all brushes of like
polarity.
As each consecutive brush is lifted there will be, in the armature circuits controlled
by that brush, either a reduced current or no current at all.
The following shows the action-
Suppose the machine is being driven as a motor with an external E.M.F. of E Volts,
and that the counter E.M.F. of each armature circuit between any two brushes is E,:
Then the difference or available E.M.F. is E - E₁ = e.
'
-Supposer = resistance of each armature circuit between any two brushes:
Then in a four pole machine the current in the armature will be as follows:

page_text: And now having particularly described and ascertained the nature of this said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In a multipolar dynamo electric machine, the combination of a commutator
whose bars are insulated from each other, with an armature in which the winding or
circuit between two commutator-bars traverses or influences each pole thereof, is
connected at each of its terminals with but a single point or bar in the commutator,
and is unconnected at any intermediate point with any other commutator-bar.
2. In a dynamo electric machine, the combination of a commutator whose bars are
insulated from each other, with an armature in which the winding between any pair
of adjoining commutator-bars traverses or influences equally each pole, is connected
at each of its terminals with but a single point or bar in the commutator, and is
unconnected directly with any other commutator-bar, in combination with three or
more brushes, substantially as and for the purpose set forth.
3. In a dynamo electric machine, the combination of the commutator whose bars
are insulated from each other with an armature in which the winding extending from
one commutator-bar to an adjoining commutator bar constitutes a circuit that extends
around the entire armature, traversing or influencing each pole thereof, is connected
at each of its terminals with but a single point or bar in the commutator, and is
unconnected at any intermediate point with any other commutator bar, substantially
as set forth.
4. An armature for dynamo electric machines in which the commutator bars are
insulated from each other and are apportioned or divided into groups, the windings
of each group constitute one layer upon the armature, the winding between adjoining
bars of any group traverses or influences equally each pole and is unconnected inter-
mediately with any other bar, and the end of the windings of each group is connected
to the first bar of the next group, in combination with brushes, substantially as and
for the purpose set forth.
5. A multipolar armature for dynamo electric machines, in which each winding
traverses and influences each pole of the armature, is connected at its beginning
with but a single commutator bar and at its end with but a single commutator bar
adjoining that from which it started and is unconnected between its terminals with
any bar, each winding ending on the commutator bar from which the next winding
starts, substantially as set forth.
Dated this 28th day of May 1889.
STANLEY CHARLES CUTHBERT CURRIE.