IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of " IMPROVEMENTS
IN DYNAMO-ELECTRIC MACHINES." A communication from abroad by Hans
Jacob Müller and Alexander Levett, both of the City, County, and State of
New York United States of Amexico Electricians
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 25th April 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. 'IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES."
[A communication from abroad by Hans Jacob Müller and Alexander Levett, both
of the City, County, and State of New York, United States of America,
Electricians.]
The object of this Invention is to provide a new and improved dynamo electric
machine, which is so constructed that a series of separate and independent currents
can be produced, of which one may be used to excite the field magnets, and at the
same time perform work in the external circuits, whereas the other currents
perform work in the external circuits only, and these different currents from the
same machine may be of various degrees of intensity.
A further object of the Invention is to provide an improved dynamo-electric
electric machine for use for various purposes, and particularly for electro plating
and analagous arts.
The object of the Invention is also to facilitate the separation of the armature
coils from the fixed field magnets, or in other words to enable them to be more
easily torn off from the field magnets and to provide an armature wheel, which
produces a current of air for preventing over heating of the magnets and armature
coils.
.
A further object of the Invention is to facilitate connecting the internal and
external circuits of a dynamo electric machine in such a manner that any one

page_text: current can be used to excite the magnets only, or to excite the magnets and
perform work in the external circuit, whereas the other currents perform work
in the external circuits only, and so that any desired current or currents can be
switched off altogether, so as not to perform any work either in the internal or
external circuits, whereby the machine can be operated with a decreased quantity
of motive power.
The Invention consists in a dynamo electric machine in which the armature is
formed of several groups of coils attached to the perforated periphery of a broad
wheel in such a manner that they are inclined to the radii of such wheel, which
wheel is mounted on a shaft provided with a series of commutators at one end
and a driving pulley at the other end, this wheel being so located in regard to the
field magnets that the wheel will be rotated between the opposite poles of the field
Inagnets.
The Invention further consists of an armature formed of as many segmental
sections as there are field magnets attached insulated to a flanged ring, the segments
being connected by insulated wires passing through the hollow shaft with the
corresponding group of armature coils."
The Invention further consists in providing the armature wheel with broad flat
spokes, and with openings in the broad periphery for the purpose of creating a
strong air current, and thereby preventing the overheating of the armature coils.
The Invention further consists in a relay ad a resistance combined with a
series of rotating armatures and fixed field agnets, whereby the reverse or
secondary current (originating in the bath of plating solution) is caused to pass
through the magnets in the same direction as the main current, and which relay will
regulate the permanent charge of the machine.
The Invention further consists in a series of switching devices in combination
with the circuits of the field magnets, the circuits of the groups of armature coils,
and the external circuits, whereby the current of the field magnets can be
connected with any one external circuit, and its corresponding circuit of the
_ armature coils.
The Invention further consists in a series of switching devices in combination
with the external circuits and the circuits of the armature coils, whereby any one
external circuit can be shut off altogether to permit operating the machine with
less motive power.
I will now describe the arrangement and construction of the field magnets,
armature commutators, and circuits of the machine in relation to producing
separate and independent currents, and for convenience of description will describe
the Invention with reference to the accompanying Drawings.
There are two series of field magnets, six in each series, arranged parallel with a
hollow shaft on which the armature wheel is mounted. The two series of magnets
are so placed relatively to each other that a pole of each magnet of one series is
opposite a pole of a magnet of the other series. The armature revolves between
the two series, and thereby generates electro motive force. The letters A' to A°
will serve to indicate the magnets of one series, and the letters B¹ to Be the
opposing inagnets of the other series..
The magnet cores are connected by brass plates, and are attached to and
supported by vertical standards C, C₁, which are fastened to a horizontal base
plate D.
Such field magnets are all connected in one circuit by means of a wire L which
proceeds from a binding post N' along the under-side of the base plate D, ascends
at x to the outer end of magnet A and is wound thereon from left to right.
From the inner or right hand end of said magnet it passes to the inner end of
magnet A2, and from the outer end of the latter to the outer end of inagnet A³, and
so on, until it leaves the outer end of magnet A, and passing down through the
base plate D reascends through the same at 2, and is wound successively on the
six magnets of the right hand series B, B3, B4, &c., passing next through the base
plate D at 3, then up through the plate at a and in the form of a coil. R to a

page_text: binding screw X' of the brush H¹ of the first or inner commutator I'. From the
binding screw Y¹ of the other brush H' of the same commutator a coiled wire J
leads down to the base D at x5 and extends to a binding post P¹ which is located
contiguous to the post N. To these respective posts are attached the negative
and positive wires which form the external circuit for maintaining a light or doing
other work. The armature wheel has eighteen coils attached to its periphery,
which coils I will designate by the letters J¹ to Js. These coils are divided into
three groups of six each (that is, as many as there are field magnets), in the
following manner:-A wire K¹ connects all the coils J¹, J', J¹, for each group'
while the coils Je for each group are connected by a second wire K2, and the coils J
are connected by a third wire K³. These wires pass through apertures in the
broad periphery of the armature wheel and then through the hollow shaft to the
respective commutators I', 12, 13, mounted on the shaft.
Each commutator consists of six segments (that is, as many as there are field
magnets) which are properly insulated and arranged concentrically within a flanged
ring, and the segments 1, 3, and 5, are connected with each other, and the segments 2,
4, and 6 are also connected with each other. The wire K' connects with the
segments 1, 3, 5, of the commutator I', passes through the hollow shaft, connects
the coils J, J, J', of an armature coil group with each other, and passes back to
the commutator and connects the segments 2, 4, and 6, of this commutator I¹.
In a like manner the wire K³ connects the segments 1, 3, 5, of the commutator I²
passes through the hollow shaft and connects all the armature coils J, J, J2, passes
back through the shaft and connects the segments 2, 4, 6, of the commutator I².
And in like manner the wire K³ connects the segments of the commutator I³ with
the coils J³, &c.
In some cases I may wind the coils of the different groups of the armature with
more than one wire of different thickness, so that different currents of different
intensity may be derived from one group, a separate commutator being in such
case provided for each wire. In this the coils J³ are wound with two wires K³
and K connected with their respective commutators in the manner described.
Each group of armature coils may contain as many coils as there are field
magnets, or it may contain any smaller number, of which number the number of
field magnets is a multiple.
I have described six field magnets but may use more or less, and as has been
stated, there must be as many commutator segments in each commutator as there
are field magnets.
Two bars G and G₁ are attached to the standard O¹ in some suitable manner and
project from the same parallel to the shaft. The brushes H1, H2, H³, and H' are
held to these bars by the binding screws W1, W2, W³, and W*, and are suitably
insulated at the point of contact. Each brusher is provided with a pressure spring U¹,
U2, US, and U, the tension of which can be adjusted by means of the set screws V₁
to V1.
The binding screws X¹ to X', and Y¹ to Y' serve to bind the positive and
negative wires of the external circuits to the corresponding brushers.
A belt pulley F is mounted on the machine shaft for rotating it, but any other
devices may be used to rotate this shaft.
The sides of the armature coils are so arranged that in the moment when they
leave one field magnet 1/8 of their cross section covers the next adjoining magnet;
consequently if the armature cheek or end leaves one magnet altogether / of
its width overlaps the next magnet. The coils are arranged in this manner for the
following reasons:-
When the coils leave the heads of the magnets, a short interruption of the main
current takes place, and in consequence of this an extra current is developed which
has the same direction as the main current; but as a certain armature coil leaves
the magnet at precisely the same time that the corresponding commutator segment
leaves the brushers, the extra current will discharge itself into the next commutator
segment in the direction of the proceeding main current, consequently in the reverse
ດ

page_text: .
direction of the succeeding current, and thus when these two currents unite they
produce a spark at the commutator, and these sparks destroy the commutator and
brushers very soon.
But if the armature coils overlap the next magnet before leaving the former one,
as described above, the following main current will be strong enough to counter
balance the extra current without affecting the preceeding main current, if the
arinatures are not too broad.
The coils of the group J¹ contain more iron than the other coils, for a certain
quantity of iron is required in the coils in proportion to the magnets to produce an
induction current, that is, sufficient to excite the magnets, and also to produce the
required reactive effect for the field magnets in turn to excite the armature cores,
As heretofore
and also their coils, and thus produce induced currents in the same.
usually constructed the armature coils of dynamo machines did not contain a
sufficient mass of iron to enable a small group of them to properly energize the field
magnets; hence as a rule all the groups had to be employed for such purpose; but
in order to obtain a current of small quantity and great intensity for maintaining
a series of lights, a certain length of wire must be employed, that is to say,
intensity of current is what is required, and with a wire of great length a current
of minimum quantity and maximum intensity may be produced. With thick cores
but a comparatively short length of wire can be employed, for the coils can occupy.
only a limited space.
In practice it has been found that while with thick coils and the necessarily short
length of wire (No. 16) that could be wound thereon, there can be produced only
one light of 1500 candle power, yet with small cores and a much greater length of
wire that can be wound thereon two such lights can be maintained. In other
words by the improved mode of constructing and winding of the armature cores,
and connecting them in the internal and external circuits, there can be produced
twice the effect usually produced by the ordinary method or arrangement.
The currents generated in the machine have the following circuits:-The current
from the first group J' of the armature coils, and which is the only one used to
excite the field magnets, and also do work in the external circuit, passes to the
segments 1, 3, 5, of commutator I', then through brush H' and spiral J to binding
post P¹, and, to the work in the external circuit. The return current enters at
binding post N¹, passes through wire L to magnet group A' to A, then through
magnet group B to B¹, and coil R to brush H¹, segments 2, 6, 4, of the same
commutator I and return wire K' back to the coils J¹, which completes the circuit.
Another current passes from the armature coils of group J2 through wire K² to
segments 1, 3, and 5, of the second commutator 12, through brush H2, binding
screw Y, wire P2, to the light in the external circuit. The negative current from
such light returns through wire N2, binding screw X2, brush H², segments 2, 6, 4,
of the same commutator 12 and return wire K² back to coils J.
÷
The two currents. from the group of coils J³ which are wound double take a
similar course through the respective commutators 13 and 14, and their respective
brushes H3 and H, and their external circuit wires P³, N³, and P4, N4, as will
be readily understood. One of these wires wound on the coil J³ derives its current
mainly by induction from the other wires, as well as by induction from the iron
core.
I am aware that it is not broadly new to arrange a series of armature coils so as
to overlap more or less of the field magnets with which they co-act; but this is
believed to be the first time that there has been conceived and practically carried
out such definite arrangement of said parts as will produce the desired effect,
namely, prevent sparks at the commutator.
The radial spokes of the armature wheel are made very broad, and when the
wheel is rotated they operate as so many fans or fan blades, forcing the air outward
from the axis of the wheel, and driving it in strong currents through its apertures
in the wheel and against and between the several coils J, J2, J³, and the heads of
the magnets, thereby preventing overheating of the same.
"

page_text: In many machines of this class water currents are employed to cool the
armature coils, and attempts have been made to attain the same results by
providing for circulation of air around and between the coils, but as far as I have
been able to learn without the success looked for. In running machines of this
kind economically this construction of the armature wheel is very important. The
cheeks or side plates of the coils do not rest on the periphery of the wheel
vertically to the same, but are slightly inclined to the radii of the wheel. They
will then not require much force to move them past the magnet heads, as they
bear off from the magnet heads much easier if they are arranged inclined instead
of vertically.
I will now proceed to describe the machine provided with a relay and a
resistance for causing the reverse or secondary current (originating in the bath of.
plating solution) to pass through the magnets in the same direction as the main
current (see Figure 2). All the connections of the magnet's coils and armature
sections are the same as those previously described, and the arrangement of the
armature coils has no relation to the relay or resistance.
The two series of magnets A1, A2, &c., and B1, B2, &c., are connected by the
wires Z2 with the binding post V which is the point where the wire I³ is attached
that connects the negative current to the electro-plating bath. The contiguous
binding post W is the one from which the positive connection is made with the
bath by means of wire Z', and I will now indicate the means for connecting it
with the parts that complete the circuit in the machine. The wire L² connects
metallically with the metal post F, and the wire R connects the latter with
brush H of commutator I' while a wire S' extends from the corresponding or
opposite brush H' to the post F2, and the wire S3 connects the latter with binding
post W. From the latter a wire F2 passes through post F2 to the brush of the
second commutator, the same being insulated in the post F2. From the corre-
sponding brush of the second commutator a wire passes through and is insulated in
post F, and thence to binding post V.
y is the armature of the relay magnet G, and Q¹ a spring to whose free end it is
attached. Q2 is a contact bracket, and X is a resistance coil connecting it with
post F on the underside of the base plate. M is a short wire that connects the
spring Q with the wire L² for purposes hereinafter specified.
The current of one of the groups of armature coils can be used for work in the
bath, and for exciting the field magnets, and the other current can be used in the
bath only, or one current may be used in the bath only, and the other for exciting
the field magnets only, as has been set forth previously.
For the sake of convenience the current generated in the armature coils J', J',
shall be designated as the first primary current, and shall be used to perform work
in the bath, and to excite the field magnets, whereas the second primary current
generated in the armature coils J2, J2, shall be used in the bath only.
The circuit of the first primary current is as follows:-It is generated in the
coils J, J, of the armature wheel (and as indicated by arrows). is conducted
through the wire K¹, to segments 1, 3, 5, of commutator I, the brush H¹, wire S¹,
post F3, wire S3 binding post W, and. thence by wire Z¹, to the anodes e² in the
bath of electro plating solution. From the work g therein, the now negative
current returns though wire Z2, binding post V, and wire L2, magnets B¹, Bº,
and A, A', to post F', wire R¹, and brush H¹, to segments 6, 4, 2, of commutator I',
and by wire K¹, back to armature coils J1, J1, J¹.
The circuit of the second primary current from the remaining six coils of the
armature, to wit, J, J, J, is through wire K2, segments 2, 4, 6, of the second
commutator and brush, wire to binding post W, wire Z to the anodes e³, and then
to the work in, the bath. From the work the now negative current proceeds by
wire through binding post V, wire insulated in the post F', second brush
seginents 1, 5, 3, of second commutator, and wire K² back to the armaturo.
coils J, J.
Thus far, that is to say, when large work is in the bath, the resistance coil ✗

page_text: and magnet G have no function; but they come into action whenever all the work
is removed, or whenever the large work is removed, and only a small piece is left
in the bath, because in such cases a reverse or secondary current is generated in
the bath of cyanide solution, and it must be short circuited, or made to take the
same course as the primary current, in order to prevent change of polarization of
the magnets, and to prevent a full charge in the machine. In other words, the
relay magnet G serves to regulate the permanent charge in the machine. at all
times, for the relay and resistance conduct the sencondary current in the direction
of the main current, and compel it to take a short circuit, as I will proceed to
explain.
If the large work be removed and only a small work be left in the bath, the
secondary current that instantly arises passes from the anodes e² along wire Z¹ to
binding post W, thence by wire S3 to the resistance coil X into contact bracket Q³
and thus into spring Q, which at that moment rests against it, owing to the
connection in the bath having been broken. From the spring Q¹ the current passes
by wire M to wire L2, thus through magnet G and to binding post V, and thus back
to work in the bath, which completes the circuit.
In such case, that is to say, when the reverse or secondary current is passing, as
just described, the primary current which carries on the process of electro deposition
in the bath is divided at the junction of coil X and wire S, so that about 2/3 of the
former current takes the usual course to the anode, via post W and wire Z¹, and the
remaining / passes through resistance coil X and along wire L2 through the field
magnets, &c.
The secondary current takes the short circuit described, because there is less
resistance than in the commutators and armature, &c.
When all the work has been removed from the bath there is no connection
through the wire Z³ that leads from the bath to binding post V; hence the
secondary current must complete its circuit by passing from the relay magnet G,
through wire L³, the field magnets B¹, B, and Aº, A¹, and post F¹, and thence by
means of a separate line mu to the bath. This separate line is thus indispensable
for a completion of the circuit through the bath when there is no work left in the
latter. But the circuit could not be properly completed in the manner required by
means of such wire alone, for the resistance to passage of the current to the bath
must not be lessened so much as to greatly increase the charge of the machine,
that is to say, by allowing field magnets and armature coils to strongly attract
each other, and thereby cause a waste of power in rotating tho armature wheel,
whose resistance to rotation then becomes very great.
•
It has been found that a carbon plate z¹ attached to the wire m and placed in
the bath, affords the desired degree of resistance, neither too much nor too little,
and thus serves as a perfect protector, not only against a too full charge, but also
prevents the strong reverse current that might produce reversal of the polarity of
the magnets.
In further explanation, and partly by way of recapitulation of the operation and
effect of the currents, I will state that when the article in the bath is small the
primary current is too weak to excite the magnet G sufficiently to cause it to
attract the armature Y with force enough to overcome the resistance of spring Q,
and thus draw down the armature y; the secondary current will continue to pass;
but whenever the amount of service of the work in the bath is sufficient to allow a
strong primary current the magnet, G attracts the armature y, and thus breaks the
short circuit through resistance coil X; thus when the bath is full of work, the
secondary current is, so to speak, forced back by the primary current, and cannot
assert itself until the primary current is weakened, which, as already indicated, may
occur through removal of a portion or all of the work in the bath.
I will now proceed to describe the arrangement of the switches for connecting
the internal and external lines in such a manner that a current from any desired
group of armature coils, can be used for work in the external circuit and for
exciting the field magnets, whereas the currents from the other group of armature

page_text: coils perform work in the external circuit only, or for connecting the lines in such
a manner that one or more currents can be switched off altogether, or that the
current of one group of armature coils can be used for exciting the magnets only,
whereas the currents from the other groups of armature coils perform work in the
external circuit only.
The field magnets A¹ to A and B¹ to B are connected with each other in the
manner described, and the end of the magnet A¹ is connected with the binding
post c, Figure 3, by the wire d, and the end of the wire d and the end of the wire
of the magnet B¹ is connected with the end of the switch knobs f¹, f³, and f³ by
the wire e.
The switch knobs g¹, g², g³, are connected with the binding post c by the
wire h. The armature coils of the group J' are connected with each other, and
the end of the wire of one end coil is connected with the corresponding section of
commutator I by the wire l, and the end of the wire of the opposite coil is
connected with the corresponding section of the commutator I¹ by the wire m', and
in a like manner the armature coils of the groups J2 and Js are connected with
their corresponding commutators 12 and Is by the wires 12 and 13 and m² and m³
respectively. The brusher H¹ of the commutator I' is connected with the switch
lever o¹ by the wire p¹, and the brusher of the commutator I¹ is connected to the
binding post 8¹ by the wire 1. In a like manner the brushers Hand H³ and h², h³,
of the commutators 12 and 13 are connected with the switch levers o2, 0³, and the
binding posts &², s³, by the wires p², p³, and 72, 73, respectively. The external
lines t¹, t, t, run from the binding posts 81, 82, 83, respectively, and are connected
with the binding post c by a ground line j. The wires 1, 2, 3, of the
brushers 1, 2, 3, are connected with the switch knobs u¹, u², u³, by the
wires w¹, w², ws, respectively, and the switch levers a¹, a², a³, are connected with
the binding post c by the wire b. The switch has been described with levers, but
pins and plates or wires may be used in place of the levers without deviating from
the Invention.
The operation is as follows:-If the current of the coils of the commutator
group J¹ is to be used for exciting the field magnets A¹ to A and B¹ to B, and to
perform work in the external circuit, the end of the switch lever o' is placed upon
the knob f', the switch levers 02 and 03 remaining on the knobs g³ and g³, as
shown. The groups J2 and Js of the armature coils will then be used for work
only.
The current generated in the armature coils of group J1 passes from the
armature through the wire to the commutator I', brushers H¹, wire p¹, switch
lever o¹, knob f¹, wire e, magnets B¹ to Bª and Aº to A¹, wire d, binding post c,
ground line j, external line t, binding post 81, wire 71, brusher h', commutator I',
wire m¹, back to the armature coils of group J'. The current of the group of
armature coils J2 passes from the armature coils through the wire to the
commutator I², brushes H², wire p², switch lever o², knob g², wire h, binding post c,
ground line j, external line t2, binding post s2, wire 72, brusher h², commutator I²,
wire m², back to group J2 of the armature coils. The current of the armature
group Ja passes through the machine and external line in a corresponding manner.
Any armature coil group may be used to change the field magnets and perform
work in the external circuit by placing the corresponding switch lever upon the
corresponding knobs f2 or f³, and the other two lines will perform work in the
external circuit only. If any current is to be switched off entirely, for instance,
the current produced by the armature coil group J¹, the switch lever a¹ is placed
upon the knob u¹, the current will then be short circuited and will pass from the
binding post c through the wire b to the lever a', knob u, wire r', to the commu-
tator and the corresponding group of armature coils.
The resistance offered by the machine is thus decreased proportionately, and
consequently the machine can be operated with less power. In a like manner one
or more lines can be switched off in case an accident should happen to these lines
or to any group of armature coils and a great waste of power is thus avoided.

page_text: If the group J of armature coils is to be used to charge the magnets, only the
switch lever o¹ is placed upon the knob f¹, and the switch lever a' upon the knob u¹,
the current will then be short circuited and will not perform any work in the
external circuit. In the same manner the current of any other group of armature
coils can be used to charge or excite the magnets, only whereas the currents of one
or more of the other groups of armature coils perform work in the external
circuit only, or may be switched off. altogether, or, in other words, short
circuited.
I have shown only three groups of armature coils and three switches for
connecting the magnet and armature currents and three switches for connecting
the external and armature currents, but I do not limit myself to this number, as
may use any number of armature groups and switches.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
25th October 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES."
A communication from abroad by Hans Jacob Müller and Alexander Levett, both
of the City, County, and State of New York, United States of America,
Electricians.
The object of this Invention is to provide a new and improved dynamo-electric
machine, which is so constructed that a scries of separate and independent currents
can be produced, of which one may be used to excite the field magnets, and at the
same time perform work in the external circuits, whereas the other currents perform
work in the external circuits only, and these different currents from the same
machine may be of various degrees of intensity.
A further object of the Invention is to provide an improved dynamo-electric
electric machine for use for various purposes, and particularly for electro plating
and analagous arts.
The object of the Invention is also to facilitate the separation of the armature
coils from the fixed field magnets, or in other words to enable them to be more
easily torn off from the field magnets, and to provide an armature wheel which
produces a current of air for preventing over heating of the magnets and armature
coils.
A further object of the Invention is to facilitate connecting the internal and
external circuits of a dynamo-electric machine in such a manner that any one
current can be used to excite the magnets only, or to excite the magnets and
perform work in the external circuit, whereas the other currents perform work in
the external circuits only, and so that any desired current or currents can be
switched off altogether, so as not to perform any work either in the internal or
external circuits, whereby the machine can be operated with a decreased quantity
of motive power.
The Invention consists in a dynamo-electric machine, in which the armature is
formed of several groups of coils attached to the perforated periphery of a broad
wheel, in such a manner that they are inclined to the radii of such wheel, which wheel
is mounted on a shaft provided with a series of commutators at one end and a driving
pulley at the other end, this wheel being so located in regard to the field magnets
that the wheel will be rotated between the opposite poles of the field magnets.
The Invention further consists of an armature formed of as many segmental
sections as there are field magnets attached, insulated to a flanged ring, the segments
being connected by insulated wires passing through the hollow shaft, with the
corresponding group of armature coils."
The Invention further consists in providing the armature wheel with broad flat
spokes, and with openings in the broad periphery for the purpose of creating a
strong air current, and thereby preventing the over-heating of the armature
coils.
The Invention further consists in a relay and a resistance combined with a series
of rotating armatures and fixed field magnets, whereby the reverse or secondary
current (originating in the bath of plating solution) is caused to pass through the
magnets in the same direction as the main current, and which relay will regulate
the permanent charge of the machine.
The Invention further consists in a series of switching devices in combination
with the eircuits of the field magnets, the circuits of the groups of armature coils,

page_text: and the external circuits, whereby the current of the field magnets can be connected
with any one external circuit and its corresponding circuit of the armature
coils.
The Invention further consists in a series of switching devices in combination
with the external circuits and the circuits of the armature coils, whereby any one
external circuit can be shut off altogether to permit of operating the machine with
less motive power.
In the accompanying Drawings,
Figure 1 is a longitudinal elevation of the improved dynamo-electric machine;
Figure 2 is a cross sectional elevation of the same on the line x, x, Figure 1;
Figure 3 is an end elevation of one of the commutators and its brushers; Figure 4.
is a plan view of the underside of the base plate of the machine without the relay
and the resistance; Figure 5 is a plan view of the underside of the base plate of
the machine, showing it provided with the relay and resistance; Figure 6 is a
longitudinal sectional elevation of the machine on the line y, y, Figure 7; Figure 7
is a cross sectional elevation of the same on the line 2, 2, Figure 6; Figure 8 is a
plan view of the front end of the top of the base plate, showing the position of the
relay; Figures 9 to 12 inclusive are diagrams illustrating the several circuits and
connections when the machine is used for electro-plating; Figure 13 is a diagram
of the field magnets, armature coils, commutators, brushers, and internal and
external circuits, and their switching devices.
Similar letters of reference indicato corresponding parts.
I will now describe the arrangement and construction of the field magnets,
armature commutators, and circuits of the machine in relation to producing
separate and independent currents, as illustrated in Figures 1 to 4 inclusive.
There are two series of field magnets, six in each series, arranged parallel with a
hollow shaft A, on which the armature wheel Z is mounted. The two series of
magnets are so placed relatively to each other that a pole of each magnet of one
series is opposite a pole of a magnet of the other series. The armature revolves
between the two series and thereby generates electro motive force. The letters A'
to A indicate the magnets of one series, and the letters B¹ to Be the opposing
magnets of the other series.
The magnet cores are connected by brass plates 01 to 0%, inclusive, and are
attached to and supported by vertical standards C, C¹, which are fastened to a
horizontal base plate D.
Such field magnets are all connected in one circuit by means of a wire L, which
proceeds from a binding post N¹ along the under side of the base plate D, ascends
at a to the outer end of magnet A1, and is wound thereon from left to right. From
the inner or right hand end of said magnet it passes to the inner end of magnet A²,
and from the outer end of the latter to the outer end of magnet A³, and so on, until
it leaves the outer end of magnet A, and passing down through the base plate D
at x (Figure 4), reascends through the same at x2, and is wound successively on the
six magnets of the right hand series B, B, B, &c.; passing next through the base
plate D at 3, then up through the plate at 4, and in the form of a coil R to a
binding screw X' of the brush H¹ of the first or inner commutator I¹ (Figure 1).
From the bing screw Y¹ of the other brush H¹ of the same commutator_a
coiled wire J leads down to the base D at a, and extends to a binding post P¹
which is located contiguous to the post. N¹. To these respective posts are
attached the negative and positive wires which form the external circuit for
maintaining a light or doing other work. The armature wheel Z has. 18 coils
attached to its periphery, which coils are designated by the letters J¹ to J³. These
coils are divided into three groups of six each (that is, as many as there are
field magnets) in the following manner :-A wire K¹ connects all the coils J¹, J¹, J¹,
for each group, while the coils J2 for each group are connected by a wire K², and
the coils J³ are connected by a wire K³. These wires pass through apertures i in
the broad periphery of the wheel Z, and then through the hollow shaft A to the
respective commutators.I', 12, 13, &c., mounted on the shaft A.

page_text: Each commutator consists of six segments (that is, as many as there are field
magnets), which are properly insulated and arranged concentrically within a
flanged ring a, and the segments 1, 3, and 5 are connected with each other, and the
segments 2, 4, and 6 are also connected with each other, as is shown in Figure 3.
The wire K connects with the segments 1, 3, 5 of the commutator I', passes
through the hollow shaft A, connects the coils J', J, J¹, of an armature coil group
with each other, and passes back to the commutator and connects the segment 2, 4,
and 6 of this commutator I¹. In a like manner the wire K2 connects the
segments 1, 3, 5 of the commutator 12, passes through the hollow shaft, and
connects all the armature coils J, J2, J2, passes back through the shaft and connects
the segments 2, 4, 6 of the commutator I². And in like manner the wire K³
connects the segments of the commutator I³ with the coils J³, &c.
In some cases I may wind the coils of the different groups of the armature with
more than one wire of different thickness, so that different currents of different
intensity may be derived from one group, a separate commutator being in such case
provided for each wire. In this the coils J³ are wound with two wires. K³ and K*;
connected with their respective commutators in the manner described.
Each group of armature coils may contain as many coils as there are field
magnets, or it may contain any smaller number, of which number the number of
field magnets is a multiple.
I have shown six field magnets, but may use more or less, and, as has been
stated, there must be as many commutator segments in each commutator as there
are field magnets.
Two bars G and G' are attached to the standard C¹ in some suitable manner,
and project from the same parallel to the shaft A. The brushers H1, H2, H3, and
Hare held to these bars by the binding screws W1, W2, W³, and W, and are
suitably insulated at the point of contact. Each brusher is provided with a
pressure spring U1, U2, U³, and U, the tension of which can be adjusted by means
of the set screws V¹ to V4
The binding screws X¹ to X', and Y₁ to Y₁, serve to bind the positive and
negative wires of the external circuits to the corresponding brushers.
A belt pulley F is mounted on the shaft A for rotating it, but any other devices
may be used to rotate this shaft.
The sides of the armature coils are so arranged that in the moment when they
leave one field magnet / of their cross section covers the next adjoining magnet,
as is shown in Figure 2, J', for instance, where 1/10 of the width of the end or
cheek of the core overlaps each of the adjoining field magnets A¹ and A", con-
sequently if the armature cheek or end leaves the magnet A altogether, 1/8th of its
width overlaps the magnet A'. The coils are arranged in this manner for the
following reasons:-
When the coils leave the heads of the magnets a short interruption of the main
current takes place, and in consequence of this an extra current is developed,
which has the same direction as the main current; but as a certain armature coil
leaves the magnet at precisely the same time that the corresponding commutator
segment leaves the brushers, the extra current will discharge itself into the next
commutator segment in the direction of the preceding main current, consequently
in the reverse direction of the succeeding current, and thus when these two
currents unite they produce a spark at the commutator, and these sparks destroy
the commutator and brushers very soon.
But if the armature coils overlap the next magnet before leaving the former
one, as described above, the following main current will be strong enough to
counterbalance the extra current without affecting the preceding main current if
the armatures are not too broad.
The coils of the group J contain more iron than the other coils, for a certain
quantity of iron is required in the coils in proportion to the magnets to produce
an induction current that is sufficient to excite the magnets, and also to produce
the required reactive effect for the field magnets in turn to excite the armature

page_text: cores and also their coils, and thus produce induced currents in the same. As
heretofore usually constructed the armature coils of dynamo-machines did not
contain a sufficient mass of iron to enable a small group of them to properly
energize the field magnets; hence, as a rule, all the groups had to be employed for
such purpose. But in order to obtain a current of small quantity and great
intensity for maintaining a series of lights, a certain length of wire must be
employed, that is to say, intensity of current is what is required, and with a wire
of great length a current of minimum quantity and maximum intensity may be
produced. With thick cores but a comparatively short length of wire cau be
employed, for the coils can occupy only a limited space.
In practice it has been found that while with thick coils and the necessarily
short length of wire (No. 16) that could be wound thereon, there can be produced
only one light of 1500 candle power, yet with small cores and a much greater
length of wire that can be wound thereon two such lights can be maintained. In
other words, by the improved mode of constructing and winding of the armature
cores and connecting them in the internal and external circuits, there can be
produced twice the effect usually produced by the ordinary method or arrangement.
The currents generated in the machine have the following circuits:-The current
from the first group J¹ of the armature coils, and which is the only one used to
excite the field magnets, and also do work in the external circuit, passes to the
segments 1, 3, 5, of commutator I', then through brush H and spiral J to binding
post P¹, and to the work in the external circuit. The return current enters at
binding post N', passes through wire L to magnet group A¹ to A, then through
magnet group B to B¹, and coil R to brush H', segments 2, 6, 4, of the same
commutator I and return wire K' back to the coils J', which completes the circuit.
Another current passes from the armature coils of group J2, through wire K² to
segments 1, 3, and 5 of the second commutator I, through brush H2, binding
screw Y², wire P2, to the light in the external circuit. The negative current from
such light returns through wire N2, binding screw X2, brush H², segments 2, 6, 4,
of the same commutator 12, and return wire K² back to coils J².
The two currents from the group of coils J³, which are wound double, take a
similar course through the respective commutators I³ and I', and their respectivo
brushes H3 and H4, and their external circuit wires P³, N3, and P4, N', as will be
readily understood. One of these wires wound on the coil J³ derives its current
mainly by induction from the other wires, as well as by induction from the
iron core.
I am aware that it is not broadly new to arrange a series of armature coils so
as to overlap more or less of the field magnets with which they co-act, but this is
believed to be the first time that there has been conceived and practically carried
out such definite arrangement of the said parts as will produce the desired effect,
namely, prevent sparks at the commutator.
The radial spokes of the armature wheel Z are made very broad, and when the
wheel is rotated they operate as so many fans or fan blades, forcing the air
outward from the axis of the wheel, and driving it in strong currents through the
apertures (Figure 7), and against and between the several coils J¹, J, J,
and the heads of the magnates, thereby preventing overheating of the same.
In many machines of this class water currents are employed to cool the armature
coils, and attempts have been made to attain the same results by providing for
circulation of air around and between the coils, but as far as I have been able to
learn without the success looked for. In running machines of this kind econo-
mically this construction of the armature wheel is very important. The cheeks or
side plates of the coils do not rest on the periphery of the wheel Z vertically to
the same, but are slightly inclined to the radii of the wheel. They will then
not require much force to move them past the magnet heads, as they tear off.
from the magnet heads much easier if they are arranged inclined instead of
⚫ vertically.
"
I will now proceed to describe the machine provided with a relay and a

page_text: resistance for causing the reverse or secondary current (originating in the bath of
plating solution), to pass through the magnets in the same direction as the main
current, as is shown in Figures 5 to 12 inclusive. In this case only two groups of
armature coils of six each, and only two commutators, are shown; but all the
connections of the magnets, coils, and armature sections are the same as those
previously described, and the arrangement of the armature coils has no relation to
or resistance.
The two series of magnets A¹, A2, &c., and B¹, B³, &c., are connected by the
wires Z with the binding post V, which is the point where the wire L² is attached
The contiguous
that connects the negative current to the electro-plating bath.
binding post W is the one from which the positive connection is made with the
bath by means of wire Z (Figure 5); and I will now indicate the means for
connecting it with the parts that complete the circuit in the machine. The wire
L2 connects metallically with the metal post F¹, and the wire R', connects the
latter with brush H' of commutator I', while a wire S¹ extends from the corresponding
or opposite brush H' to the post F2, and the wire S³ connects the latter with
binding post W. From the latter a wire S2 (Figure 10) passes through post F2 to
the brush H2 of the second commutator I, the same being insulated in the post
F. From the corresponding brush H³ of the second commutator 12 a wire R²
passes through, and is insulated in post F¹, and thence to binding post V.
Referring to Figures 5, 6, and 8, Y is the armature of the relay magnet G, and
Qa spring, to whose free end it is attached. Q2 is a contact bracket, and X is a
resistance coil connecting it with post F2 on the underside of the base plate D.
M is a short wire that connects the spring Q¹ with the wire L2, for the purposes
hereinafter specified.
The current of one of the groups of armature coils can be used for work in the
bath and for exciting the field magnets, and the other current can be used in the
bath only, or one current may be used in the bath only, and the other for exciting
the field magnets only, as has been set forth previously.
For the sake of convenience the current generated in the armature coils J¹, J¹,
shall be designated as the first primary current, and shall be used to perform
work in the bath and to excite the field magnates; whereas the second primary
current generated in the armature coils J2, J2, shall be used in the bath only.
The circuit of the first primary current (Figure 9) is as follows:-It is generated in
the coils J, J, of the armature wheel Z (and as indicated by arrows), is conducted
through the wire K¹ to segments 1, 3, 5, of commutator I', the brush H', wire St,
post F2, wire S, binding post W, and thence by wire Z' to the anodes e² in the
bath of electro plating solution. From the work g therein the now negative
current returns through wire Z2, binding post V, and wire L², magnets B', B, and
A, A, to post F¹, wire R¹, and brush H, to segments 6, 4, 2, of commutator I', and
by wire K back to armature coils J¹, J¹, J¹.
The circuit of the second primary current from the remaining six coils of the
armature, to wit, J, J2, J2, is through wire K2 (Figure 10), segments 2, 4, 6, of
the cominutator I³, brush H³, wire S2, and binding post W, wire Z', to the
anodes e2, and then to the work g in the bath. From the work the now negative
current proceeds by wire Z2 through binding post V, wire R² insulated in the
post F, brush H2, segments 1, 5, 3, of commutator I2, and wire K back to the
armature coils J2, J2
Thus far, that is to say, when large work is in the bath (Figures 9 and 10) the
resistance coil X and magnet G have no function, but they come into action
whenever all the work is removed, or whenever the large work is removed and only
a small piece is left in the bath, because in such cases a reverse or secondary
current is generated in the bath of cyanide solution, and it must be short circuited
or made to take the same course as the primary current in order to prevent change
of polarization of the magnets, and to prevent a full charge in the machine. In
other words the relay magnet G serves to regulate the permanent charge in the
imachine at all times, for the relay and resistance conduct the secondary current in

page_text: the direction of the main current, and compel it to, take a short circuit, as I will
proceed to explain.
If the large work be removed and only a small work be left in the bath, as
shown in Figure 11, the secondary current that instantly arises passes from the
anodes e² along wire Z' to binding post W, thence by wire S³ to the resistance
coil X into contact bracket Q2, and thus into spring Q¹, which at that moment
rests against it, owing to the connection in the bath having been broken. From
the spring Q the current passes by wire M to wire L², thus through magnet G
and to binding post V, and thus back to work in the bath which completes the
circuit.
In such case, that is to say, when the reverse or secondary current is passing, as
just described, the primary current which carries on the process of electro
deposition in the bath is divided at the junction of coil X and wire S³, so that
about 2/3rds. of the former current takes the usual course to the anode via post W
and wire Z, and the remaining 1/3rd. passes through resistance coil X and along
wire L' through the field magnets, &c.
The secondary current takes the short circuit described, because there is less
resistance than in the commutators and armature, &c. In Figure 12 I have shown
the course of the reverse or secondary current when all the work has been removed
from the bath. It will be noted that there is then no connection through the
wire Z that leads from the bath to binding post V.; hence the secondary current
must complete its circuit by passing from the relay magnet G through wire L², the
field magnets B1, B6, and A, A', and post F¹, and thence by means of a separate
line m to the bath. This separate line is thus indispensable for a completion of the
circuit through the bath when there is no work left in the latter; but the circuit
could not be properly completed in the manner required by means of such wire
alone, for the resistance to passage of the current to the bath must not be lessened
so much as to greatly increase the charge of the machine, that is to say, by allowing
field magnets and armature coils to strongly attract each other, and thereby cause
a waste of power in rotating the armature wheel, whose resistance to rotation then
becomes very great.
.
It has been found that a carbon plate 21 attached to the wire m and placed in
the bath (Figures 9 to 12 inclusive) affords the desired degree of resistance, neither
too much nor too little, and thus serves as a perfect protector, not only against a
too full charge, but also prevents the strong reverse current that might produce
reversal of the polarity of the magnets.
In further explanation, and partly by way of recapitulation of the operation
and effect of the currents, I will state that when the article in the bath is small
the primary current is too weak to excite the magnet G sufficiently to cause it to
attract the armature Y with force enough to overcome the resistance of spring Q¹,
and thus draw down the armature y; the secondary current will continue to pass,
as indicated in Figures 11 and 12; but whenever the amount of service of the work
in the bath is sufficient to allow a strong primary current the magnet G attracts
the armature y, and thus breaks the short circuit through resistance coil X. Thus
when the bath is full of work the secondary current is, so to speak, forced back by
the primary current, and cannot assert itself until the primary current is weakened,
which, as already indicated, may occur through removal of a portion or all of the
work in the bath.
I will now proceed to describe the arrangement of the switches for connecting
the internal and external lines in such a manner that a current from any desired
group of armature coils can be used for work in the external circuit and for
exciting the field magnets, whereas the currents from the other group of armature
coils perform work in the external circuit only, or for connecting the lines in such
a manner that one or more currents can be switched off altogether, or that the
current of one group of armature coils can be used for exciting the magnets only,
whereas the currents from the other groups of armature coils perform work in the
external circuit only.

page_text: The field magnets A¹ to Aº, and B¹ to B, are connected with each other in the
manner described, and the end of the magnet A¹ is connected with the binding
post c by the wire d, and the end of the wire of the magnet B' is connected with
the end of the switch knobs f¹, f2, and f3 by the wire e. The switch knobs g¹, g², g³,
are connected with the binding post c by the wire h. The armature coils of the
group J are connected with each other, and the end of the wire of one end coil is
connected with the corresponding section of commutator I¹ by the wire l', and the
end of the wire of the opposite coil is connected with the corresponding section of
the commutator I' by the wire m', and in a like manner the armature coils of the
groups J and Js are connected with their corresponding commutators 12 and 13 by
the wires 2 and 3, and m2 and m³ respectively. The brusher H¹ of the com-
mutator I is connected with the switch lever o' by the wire p¹, and the brusher h¹
of the commutator I' is connected to the binding post 8' by the wire r¹. In a like
manner the brushers H2 and Hs, and h2, h3, of the commutators 12 and I³ are
connected with the switch levers 02, 0³, and the binding posts 82, 83, by the
wires p, p, and 22, 23, respectively. The external lines t¹, 2, 3, run from the
binding posts 81, 82, 83, respectively, and are connected with the binding post c by a
ground line j. The wires 1, 2, 3, of the brushers h1, h2, hs, are connected with the
switch knobs u', u², u³, by the wires w¹, w, w³, respectively, and the switch
levers a¹, a², as, are connected with the binding post c by the wire b. The switch
has been described with levers, but pins and plates or wires may be used in place
of the levers without deviating from the Invention.
The operation is as follows:-If the current of the coils of the commutator
group J' is to be used for exciting the field magnets A¹ to A6, and B' to B, and to
perform work in the external circuit, the end of the switch lever o¹ is placed upon
the knob f¹, the switch levers o² and o³ remaining on the knobs g² and g³, as shown.
The groups J and J³ of the armature coils will then be used for work only.
The current generated in the armature coils of group J¹ passes from the armaturo
in the direction of the arrow through the wire l' to the commutator I', brushers H¹,
wire p, switch lever o', knob f', wire e, magnets B1 to B6, and A6 to A¹, wire d,
binding post c, ground line j, external line t¹, binding post s¹, wire 2, brusher h¹,
commutator I', wire mt, back to the armature coils of group J¹. The current of
the group of armature coils J2 passes from the armature coils through the wire 12
to the commutator I, brushers H2, wire p², switch lever o³, knob g², wire h, binding
post c, ground line j, external line 2, binding post s², wire 72, brusher h², com-
mutator I, wire m², back to group J2 of the armature coils. The current of thic
armature group J³ passes through the machine and external line in a corresponding
manner. Any armature coil group may be used to change the field magnets and
perform work in the external circuit by placing the corresponding switch lever
upon the corresponding knobs f2 or f³, and the other two lines will perform work
in the external circuit only. If any current is to be switched off entirely, for
instance, the current produced by the armature coil group J1, the switch lever a¹ is
placed upon the knob w¹; the current will then be short circuited, and will pass.
from the binding post c, through the wire b to the leyer a¹, knob u, wire 7¹, to the
commutator and the corresponding group of armature coils.
The resistance offered by the machine is thus decreased proportionately, and
consequently the machine can be operated with less power. In a like manner one or
more lines can be switched off in case an accident should happen to these lines, or
to any group of armature coils, and a great waste of power is thus avoided.
If the group J of armature coils is to be used to charge the magnets only, the
switch lever o is placed upon the knob f¹, and the switch lever a¹ upon the
knob u; the current will then be short circuited, and will not perform any work
in the external circuit. In the same manner the current of any other group of
armature coils can be used to charge or excite the magnets, only whereas the
currents of one or more of the other groups of armature coils perform work in the
external circuit only, or may be switched off altogether, or in other words, short
cifcuited.

page_text: I have shown only three groups of armature coils and three switches for
connecting the magnet and armature currents, and three switches for connecting
the external and armature currents, but I do not limit myself to this number, as I
may use any number of armature groups and switches.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what claim as the Invention to be protected by the
hereinbefore in part recited Letters Patent is,-
1st. In combination with two or more commutators and a series of field
magnets a series of armature coils which are divided into groups, the coils of each
group being connected with each other. and with a separate commutator, sub-
stantially as described, for the purpose of producing several independent and
separate external currents at the same time, as set forth.
2nd. The combination with commutators and series of field magnets of an
armature wheel having two or more différent. series of coils, the coils Jof one
series having larger iron cores than those of the rest, and being wound with a less
length of wire, and such larger cores being connected with a commutator and the
magnets, and the other series of coils wound with a greater length of wire which
leads to the other commutators, as shown and described, the current from the coils
having the larger iron cores being used to excite the magnets, and the current from
the others exclusively to do work in the external circuit, as and for the purpose
specified.
3rd. The combination with a commutator and a series of field magnets con-
centrically arranged of an armature wheel having a series of coils, the width of
whose checks exceeds by about one eighth the distance between such magnets so
as they will overlap the latter, as shown, for the purpose of preventing sparks at the
commutator, substantially as specified.
4th. In a group of coils of the armature of a dynamo-electric machine the
combination with one or more coils J2 or Js of a coil J having a larger iron core
than the other coils, substantially as herein shown and described, and for the
purpose of producing more magnetism for exciting the field magnets in these
coils J than in the rest.
5th. In the armature of a dynamo-electric machine the combination of a series
of coils in number equal to a multiple of the number of field magnets of coils which
have a larger iron core than the rest of the coils and are equal in number to the
number of field inagnets in the machine, substantially as herein shown and
described, and for the purpose of exciting the field imagnets of the machine with a
number of coils not greater than the number of field magnets, so that the other
coils can be used independently for work in the external circuit.
6th. In a dynamo-electric machine the combination of the negative wire with
a relay and a resistance, substantially as shown and described, for the purpose of
conducting the secondary current through the field magnets in the same direction
as the main current, and to regulate the permanent charge of the machine.
7th. In a dynamo-electric machine the rotating armature wheels having open
sides and a series of broad spokes, arranged radially and severally parallel to its
axis, and the broad periphery having openings i, i, between the spokes, all as shown
and described, to operate as and for the purpose specified.
8th. In a dynamo-electric, machine the combination with the field magnets
and two or more commutators with a series of armature coils formed of wires of
different sizes, each one being connected with a separate commutator, whereby
several currents of different intensity for external work are generated by the same
machine, substantially as described.
9th. In a dynamo-electric machine the combination with the field magnets of
an armature wheel having its coils J, J, J³, placed in an inclined position to the
radii of said wheel, substantially as herein shown and described and for the purpose
specified.
10th. In a dynamo electric machine the combination with two or more internal
circuits of two or more switching devices whereby any desired current can be used
1

page_text: for work in the internal and external circuits, whereas the other currents perform
work in the external circuit only, as set forth.
11th. In a dynamo electric machine, the combination with two or more
internal circuits and two or more external circuits of two or more switching devices,
whereby any desired current can be switched off altogether, so as not to perform
any labour in the internal nor external circuits, thus permitting the machine to be
operated with decreased power, as set forth.
12th. In a dynamo electric machine, the combination with two or more
internal circuits and two or more external circuits of two or more switching
devices for connecting the armature circuits and magnet circuits, and two or more
switching devices for connecting the armature circuits and the external circuits,
whereby the current of any desired group of armature coils can be used to charge
the magnets only, whereas the other currents are used for work in the external
circuits only, as set forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty fourth day of October, A.D. 1881.