Improvements in Current Collectors for Dynamo-electric Machines.
Year: 1898

page_text: Date of Application, 1st Mar., 1898-Accepted, 16th Apr., 1898
COMPLETE SPECIFICATION.
Improvements in Current Collectors for Dynamo-electric Machines.
I, GEORGE WILLIAM NELL, of 878, Marshall Street, in the City of Philadelphia,
State of Pennsylvania, United States of America, Mechanical Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following state-
ment-
The object of my invention is to so construct current collectors for dynamo
electric machines as to overcome the objections (such for example as excessive
friction, and wear of the parts, loss of current and difficulty in effecting repairs)
which are incidental to the commutators and brushes now generally employed in
connection with such machines.
This object I attain in the manner hereinafter set forth, reference being had to
the accompanying drawings, in which Figure 1 is a section of sufficient of a dynamo
electric machine to illustrate a current collector, constructed in accordance with
my invention; Figure 2 is an outer end view of the current collector; Figures 3
to 7 inclusive are transverse sections, Figure 3 being taken on the line v. v.
Figure 1; Figure 4 on the line ww Figure 1; Figure 5 on the line x Figure 1;
Figure 6 on the line y y Figure 1; and Figure 7 on the line Figure 1;
Figures 8 and 9 are enlarged views illustrating one of the features of my invention.
1 represents the shaft of the armature having, wound upon the same, a series of
armature coils 2, of which there may be any desired number, each end of each coil
having an exposed terminal 3 at the inner end of a hub 4 of wood, or other suitable
material which is mounted as shewn upon the armature shaft at the end of the
armature.
Each end of each coil is also connected by means of a cross wire 5 to an exposed
terminal 6 at the outer end of the said hub 4 and diametrically opposite the exposed
terminal 3 of the armature coil.
To yokes 7 mounted upon-the hub 4 are hung. levers 9, as many of these levers
being employed as there are coils on the armature, so that the inner end of each
lever projects over the exposed terminal 3.of one end of each armature coil while
the outer end of the said lever projects over the exposed terminal 6 of the opposite
end of the said armature coil, thus if the terminal 3, at the inner end of the lever,
represents the positive end of the armature coil the terminal 6, at the outer end of
the said lever, represents the negative end of the said armature coil.
Between each exposed terminal 3 at the inner end of the hub 4 and the inner
end of the corresponding lever 9 is interposed the front end of a current
connector 10, the outer end of which is secured to a current collecting ring 11,
mounted upon the hub 4, and connected, by means of a leading wire 12, to a
current distributing ring 13, mounted upon, but insulated from, the shaft 1, of the
armature.
:.
The exposed outer terminal 6, of each of the armature coils is bent inward over
the hub 4 as shewn in Figure 1, and beneath this inwardly bent terminal 6,
projects the outer free end of a current connector 14, which passes through an
insulating sleeve 15 carried by a loop 16, depending from the outer end of the

page_text: lever 9, corresponding to said terminal 6, the inner end of the said current
connector 14, being secured to a current collecting ring 17, which is mounted upon
the hub 4, and is in electrical connection, through a leading wire 18, with a
ring 19, mounted upon, but insulated from, the armature shaft 1. The current
connectors 10, hive such resiliency that they will normally tend to press outwards
the inner ends of the levers 9, which will thus be removed from contact with the
terminals 3 of the armature coils. At the same time the connectors 14, by their
resiliency, will press inwards the outer ends of the levers 9 and withdraw the
connectors 14 from contact with the terminals 6 of the said coils.
The inner end of each lever 9 has a sleeve 20 of insulating material in order to
prevent electrical contact of the said lever with the current connector 10, and
underneath the loop 16, of each of the current connectors 14, is a pad 21 of rubber,
or other sound deadening material, as shewn in Figures 1 and 4.
Outward of the outer ends of the levers 9 is mounted a magnet, or magnets, 22,
which, preferably, are permanent magnets, but which inay be electro-magnets
which are exited by the current from a galvanic battery, or dynamo.
In case permanent magnets are used, these may also have wrappings of wire, as
shewn for instance by dotted lines, in Figure 2 for the purpose of higher excitation,
if necessary.
Each lever 9, or at least that part of each lever which passes beneath the magnet,
should be of iron, or steel, in order that it may be readily attracted by the said
magnet.
In the present instance I have shewn the magnet as composed of two bars 22,
presenting similar poles at their inner ends, the levers 9, constituting swinging
armatures for this magnet, so that, as the outer end of each lever passes the said
magnet, it will be attracted and moved outwards thereby, the inner end of the lever
being simultaneously moved inwards so that the current connectors 10 and 14
controlled by the said lever will be caused to make connection with the exposed
terminals 3 and 6 of the armature coil corresponding with the said lever, so that,
through the medium of the said connectors, the collecting rings 11 and 17, and the
leading wires 12 and 18, the ring 13 of the armature shaft will be electrically
connected with the terminal 3 of the armature coil and the ring 19 will be
electrically connected with the terminal 6 of the said coil, hence, supposing that
the terminal 3 represents the positive end of the coil, the ring 13 will become
the positive ring of the current collector, and the ring 19 will become the negative
ring, the said rings rotating in contact with springs, brushes, or other usual or
suitable conductors.
"
As the levers 9 successively pass under the magnet one, or more, of the levers
will always be attracted thereby, hence the armature coils will be successively
placed in connection with the rings 13 and 19.
The magnets 22, can be mounted in a rocker so as to be adjusted across the ends
of the levers 9, in the same manner, and for the same purpose, as commutator
brushes are now adjusted in respect to the neutral points of the armature.
In order to provide a simple means for securing to the levers 9, the pivot pins 24,
whereby they are hung to the brackets 7, and the pins 25, which carry the
loops 16, I simply form in the edge of the lever a recess 26 with a round bottom
the pin being inserted into this recess as shewn in Figure 8, and the edges of the
lever at the end of the recess being then caulked, or swaged in over the pin as
shewn in Figure 9, thus dispensing with expensive boring, or drilling, operations.
It will be understood that all of the connecting wires are properly insulated,
except at points where contacts have to be made.
Among the advantages incident to the use of my invention may be mentioned
the almost complete absence of mechanical friction with attendant wear, in place
of which there is but a slight magnetic friction, hence a considerable saving in
driving power is attained, and as no lubrication of the parts is required there is
no such accumulation of dirt, as is the case when oil is used.

page_text: The collector is practically noiseless in its operation, and, as the commuting of
the current is done at the top of the collector, both inspection and repair can be
readily effected.
For large machines the hub 4, and the other parts of the collector, may be
enlarged in proportion without increasing the friction except against the air, but
the greater draught of air is of benefit in keeping the parts of the collector cool.
In machines having four, six, eight, or more, poles a single current collector at
the top of the hub will be sufficient to collect all of the current and in this way
saving is effected in driving power, in commutator brushes, and attendance, in fact,
my improved current collector reduces the need of attendance and adjustment and
renewal of parts to a minimum, thereby reducing both the initial cost of the
machine and the cost of maintenance. Furthermore, all the generated current will
be carried off without loss caused by short circuiting, or sparking, as the circuit is
never opened and perfect contact is always made precisely at the right moment,
and at the right place, hence the hurtful effects of self-induction in the field and
armature coils, caused by interrupting the circuit and manifested by sparking, are
entirely eliminated, as each armature coil must deliver its current promptly when
connection is made with its opposite terminals.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a current collector for dynamo electric machines, the combination of the
armature coils, current distributors, a magnet, or magnets, levers rotating with the
armature and controlled by the said magnet or magnets, and contact devices
operated by said levers, whereby the connection of the opposite ends of the
armature coils with the current distributors is effected at the proper time.
2. In a current collector for dynamo electric machines, the combination of the
armature coils, current distributors, a magnet or magnets situated outward of the
collector, levers rotating with the armature and controlled by the said magnet, or
magnets, and contact devices operated by the said levers, whereby the connection
of the opposite ends of the armature coils with the current distributors is effected
at the proper time, and both connections are made at the top of the collector.
3. In a current collector for dynamo electric machines, the combination of the
armature coils, a magnet or magnets, levers rotating with the armature, and
controlled by the said magnet or magnets, connectors operated by the said levers
and moved thereby into contact with the terminals of the armature coils, and
collector rings receiving the current from the said connectors.
4. In a current collector for dynamo electric machines, the combination of the
armature coils, current distributors, a magnet, or magnets, levers rotating with the
armature, and controlled by the said magnet, or magnets, connectors operated by
the said levers, and moved thereby into contact with the terminals of the armature
coils, collector rings receiving the current from the said connectors, and electrical
connections between the said collector rings and the current distributors.
5. In a current collector for dynamo electric machines, the combination of the
armature coils, current distributors, a magnet, or magnets, levers rotating with the
armature and controlled by the said magnet or magnets, connectors operated by
the said levers, and moved thereby into contact with the terminals of the armature
coils, the said connectors having such resiliency as normally to be retained out of
contact with the said terminals, and electrical connections between the said
connectors and the current distributors.
.
6. In a current collector for dynamo electric machines, the combination of a
magnet, or magnets, levers rotating with the armature shaft and successively
brought under the influence of the said magnet or magnets, armature coils each having
one terminal adjacent to one arm of the lever, and the other terminal adjacent to
the other arm of the lever, current distributors, and contact devices operated by the
said levers.

page_text: 7. In a current collector for dynamo electric machines, the combination of a
magnet or magnets, levers rotating with the armature shaft and carried successively
under the influence of the said magnet or magnets, armature coils, having at each
end terminals adjacent to each end of one of the said levers, current distributors,
and contact devices operated by the said levers.
8. In a current collector for dynamo electric machines the combination of a lever
having a recess in one side of the same, and a pin seated in said recess and retained
therein by portions of the opposite walls of the recess swaged down upon the
pin.
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1 1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.